diff --git a/src/cpp/mip/metadata/definitions/commands_3dm.hpp b/src/cpp/mip/metadata/definitions/commands_3dm.hpp
index 5d661329..abf2df65 100644
--- a/src/cpp/mip/metadata/definitions/commands_3dm.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_3dm.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<commands_3dm::PollImuMessage>
             /* .name          = */ "suppress_ack",
             /* .docs          = */ "Suppress the usual ACK/NACK reply.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::suppress_ack>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::suppress_ack>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -29,7 +29,7 @@ struct MetadataFor<commands_3dm::PollImuMessage>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors in the descriptor list.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -38,7 +38,7 @@ struct MetadataFor<commands_3dm::PollImuMessage>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {83, microstrain::Index(1) /* num_descriptors */},
             /* .condition     = */ {},
@@ -67,7 +67,7 @@ struct MetadataFor<commands_3dm::PollGnssMessage>
             /* .name          = */ "suppress_ack",
             /* .docs          = */ "Suppress the usual ACK/NACK reply.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::suppress_ack>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::suppress_ack>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -76,7 +76,7 @@ struct MetadataFor<commands_3dm::PollGnssMessage>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors in the descriptor list.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -85,7 +85,7 @@ struct MetadataFor<commands_3dm::PollGnssMessage>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {83, microstrain::Index(1) /* num_descriptors */},
             /* .condition     = */ {},
@@ -114,7 +114,7 @@ struct MetadataFor<commands_3dm::PollFilterMessage>
             /* .name          = */ "suppress_ack",
             /* .docs          = */ "Suppress the usual ACK/NACK reply.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::suppress_ack>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::suppress_ack>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -123,7 +123,7 @@ struct MetadataFor<commands_3dm::PollFilterMessage>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors in the format list.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -132,7 +132,7 @@ struct MetadataFor<commands_3dm::PollFilterMessage>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor format list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {83, microstrain::Index(1) /* num_descriptors */},
             /* .condition     = */ {},
@@ -161,7 +161,7 @@ struct MetadataFor<commands_3dm::ImuMessageFormat::Response>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -170,7 +170,7 @@ struct MetadataFor<commands_3dm::ImuMessageFormat::Response>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor format list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(0) /* num_descriptors */},
             /* .condition     = */ {},
@@ -200,7 +200,7 @@ struct MetadataFor<commands_3dm::ImuMessageFormat>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -209,7 +209,7 @@ struct MetadataFor<commands_3dm::ImuMessageFormat>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor format list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(0) /* num_descriptors */},
             /* .condition     = */ {},
@@ -238,7 +238,7 @@ struct MetadataFor<commands_3dm::GpsMessageFormat::Response>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -247,7 +247,7 @@ struct MetadataFor<commands_3dm::GpsMessageFormat::Response>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor format list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(0) /* num_descriptors */},
             /* .condition     = */ {},
@@ -277,7 +277,7 @@ struct MetadataFor<commands_3dm::GpsMessageFormat>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -286,7 +286,7 @@ struct MetadataFor<commands_3dm::GpsMessageFormat>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor format list.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(0) /* num_descriptors */},
             /* .condition     = */ {},
@@ -315,7 +315,7 @@ struct MetadataFor<commands_3dm::FilterMessageFormat::Response>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors (limited by payload size)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -324,7 +324,7 @@ struct MetadataFor<commands_3dm::FilterMessageFormat::Response>
             /* .name          = */ "descriptors",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(0) /* num_descriptors */},
             /* .condition     = */ {},
@@ -354,7 +354,7 @@ struct MetadataFor<commands_3dm::FilterMessageFormat>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors (limited by payload size)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -363,7 +363,7 @@ struct MetadataFor<commands_3dm::FilterMessageFormat>
             /* .name          = */ "descriptors",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(0) /* num_descriptors */},
             /* .condition     = */ {},
@@ -392,7 +392,7 @@ struct MetadataFor<commands_3dm::ImuGetBaseRate::Response>
             /* .name          = */ "rate",
             /* .docs          = */ "[hz]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::rate>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::rate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -438,7 +438,7 @@ struct MetadataFor<commands_3dm::GpsGetBaseRate::Response>
             /* .name          = */ "rate",
             /* .docs          = */ "[hz]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::rate>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::rate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -484,7 +484,7 @@ struct MetadataFor<commands_3dm::FilterGetBaseRate::Response>
             /* .name          = */ "rate",
             /* .docs          = */ "[hz]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::rate>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::rate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -530,7 +530,7 @@ struct MetadataFor<commands_3dm::PollData>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Data descriptor set. Must be supported.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -539,7 +539,7 @@ struct MetadataFor<commands_3dm::PollData>
             /* .name          = */ "suppress_ack",
             /* .docs          = */ "Suppress the usual ACK/NACK reply.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::suppress_ack>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::suppress_ack>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -548,7 +548,7 @@ struct MetadataFor<commands_3dm::PollData>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors in the format list.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -557,7 +557,7 @@ struct MetadataFor<commands_3dm::PollData>
             /* .name          = */ "descriptors",
             /* .docs          = */ "Descriptor format list.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(2) /* num_descriptors */},
             /* .condition     = */ {},
@@ -586,7 +586,7 @@ struct MetadataFor<commands_3dm::GetBaseRate::Response>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Echoes the parameter in the command.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -595,7 +595,7 @@ struct MetadataFor<commands_3dm::GetBaseRate::Response>
             /* .name          = */ "rate",
             /* .docs          = */ "Base rate in Hz (0 = variable, unknown, or user-defined rate.  Data will be sent when received).",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::rate>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::rate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -624,7 +624,7 @@ struct MetadataFor<commands_3dm::GetBaseRate>
             /* .name          = */ "desc_set",
             /* .docs          = */ "This is the data descriptor set. It must be a supported descriptor.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -653,7 +653,7 @@ struct MetadataFor<commands_3dm::MessageFormat::Response>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Echoes the descriptor set from the command.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -662,7 +662,7 @@ struct MetadataFor<commands_3dm::MessageFormat::Response>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors in the list.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -671,7 +671,7 @@ struct MetadataFor<commands_3dm::MessageFormat::Response>
             /* .name          = */ "descriptors",
             /* .docs          = */ "List of descriptors and decimations.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(1) /* num_descriptors */},
             /* .condition     = */ {},
@@ -701,7 +701,7 @@ struct MetadataFor<commands_3dm::MessageFormat>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Data descriptor set. Must be supported. When function is SAVE, LOAD, or DEFAULT, can be 0 to apply to all descriptor sets.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -710,7 +710,7 @@ struct MetadataFor<commands_3dm::MessageFormat>
             /* .name          = */ "num_descriptors",
             /* .docs          = */ "Number of descriptors (limited by payload size)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -719,7 +719,7 @@ struct MetadataFor<commands_3dm::MessageFormat>
             /* .name          = */ "descriptors",
             /* .docs          = */ "List of descriptors and decimations.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<DescriptorRate>::value},
-            /* .accessor      = */ utils::access<type, DescriptorRate, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, DescriptorRate, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {82, microstrain::Index(1) /* num_descriptors */},
             /* .condition     = */ {},
@@ -796,7 +796,7 @@ struct MetadataFor<commands_3dm::NmeaMessage>
             /* .name          = */ "message_id",
             /* .docs          = */ "NMEA sentence type.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::NmeaMessage::MessageID>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::NmeaMessage::MessageID, &type::message_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::NmeaMessage::MessageID, &type::message_id>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -805,7 +805,7 @@ struct MetadataFor<commands_3dm::NmeaMessage>
             /* .name          = */ "talker_id",
             /* .docs          = */ "NMEA talker ID. Ignored for proprietary sentences.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::NmeaMessage::TalkerID>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::NmeaMessage::TalkerID, &type::talker_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::NmeaMessage::TalkerID, &type::talker_id>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -814,7 +814,7 @@ struct MetadataFor<commands_3dm::NmeaMessage>
             /* .name          = */ "source_desc_set",
             /* .docs          = */ "Data descriptor set where the data will be sourced. Available options depend on the sentence.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source_desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source_desc_set>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -823,7 +823,7 @@ struct MetadataFor<commands_3dm::NmeaMessage>
             /* .name          = */ "decimation",
             /* .docs          = */ "Decimation from the base rate for source_desc_set. Frequency is limited to 10 Hz or the base rate, whichever is lower. Must be 0 when polling.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::decimation>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::decimation>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -848,7 +848,7 @@ struct MetadataFor<commands_3dm::NmeaPollData>
             /* .name          = */ "suppress_ack",
             /* .docs          = */ "Suppress the usual ACK/NACK reply.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::suppress_ack>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::suppress_ack>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -857,7 +857,7 @@ struct MetadataFor<commands_3dm::NmeaPollData>
             /* .name          = */ "count",
             /* .docs          = */ "Number of format entries (limited by payload size)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -866,7 +866,7 @@ struct MetadataFor<commands_3dm::NmeaPollData>
             /* .name          = */ "format_entries",
             /* .docs          = */ "List of format entries.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::NmeaMessage>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::NmeaMessage, &type::format_entries>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::NmeaMessage, &type::format_entries>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {40, microstrain::Index(1) /* count */},
             /* .condition     = */ {},
@@ -895,7 +895,7 @@ struct MetadataFor<commands_3dm::NmeaMessageFormat::Response>
             /* .name          = */ "count",
             /* .docs          = */ "Number of format entries (limited by payload size)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -904,7 +904,7 @@ struct MetadataFor<commands_3dm::NmeaMessageFormat::Response>
             /* .name          = */ "format_entries",
             /* .docs          = */ "List of format entries.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::NmeaMessage>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::NmeaMessage, &type::format_entries>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::NmeaMessage, &type::format_entries>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {40, microstrain::Index(0) /* count */},
             /* .condition     = */ {},
@@ -934,7 +934,7 @@ struct MetadataFor<commands_3dm::NmeaMessageFormat>
             /* .name          = */ "count",
             /* .docs          = */ "Number of format entries (limited by payload size)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -943,7 +943,7 @@ struct MetadataFor<commands_3dm::NmeaMessageFormat>
             /* .name          = */ "format_entries",
             /* .docs          = */ "List of format entries.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::NmeaMessage>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::NmeaMessage, &type::format_entries>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::NmeaMessage, &type::format_entries>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {40, microstrain::Index(0) /* count */},
             /* .condition     = */ {},
@@ -994,7 +994,7 @@ struct MetadataFor<commands_3dm::UartBaudrate::Response>
             /* .name          = */ "baud",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::baud>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::baud>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1024,7 +1024,7 @@ struct MetadataFor<commands_3dm::UartBaudrate>
             /* .name          = */ "baud",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::baud>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::baud>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1073,7 +1073,7 @@ struct MetadataFor<commands_3dm::FactoryStreaming>
             /* .name          = */ "action",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::FactoryStreaming::Action>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::FactoryStreaming::Action, &type::action>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::FactoryStreaming::Action, &type::action>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1082,7 +1082,7 @@ struct MetadataFor<commands_3dm::FactoryStreaming>
             /* .name          = */ "reserved",
             /* .docs          = */ "Reserved. Set to 0x00.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1111,7 +1111,7 @@ struct MetadataFor<commands_3dm::DatastreamControl::Response>
             /* .name          = */ "desc_set",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1120,7 +1120,7 @@ struct MetadataFor<commands_3dm::DatastreamControl::Response>
             /* .name          = */ "enabled",
             /* .docs          = */ "",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enabled>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enabled>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1150,7 +1150,7 @@ struct MetadataFor<commands_3dm::DatastreamControl>
             /* .name          = */ "desc_set",
             /* .docs          = */ "The descriptor set of the stream to control. When function is SAVE, LOAD, or DEFAULT, can be ALL_STREAMS(0) to apply to all descriptor sets.\nOn Generation 5 products, this must be one of the above legacy constants.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1159,7 +1159,7 @@ struct MetadataFor<commands_3dm::DatastreamControl>
             /* .name          = */ "enable",
             /* .docs          = */ "True or false to enable or disable the stream.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1229,7 +1229,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Settings>
             /* .name          = */ "constellation_id",
             /* .docs          = */ "Constellation ID",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::ConstellationSettings::ConstellationId>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::ConstellationSettings::ConstellationId, &type::constellation_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::ConstellationSettings::ConstellationId, &type::constellation_id>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1238,7 +1238,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Settings>
             /* .name          = */ "enable",
             /* .docs          = */ "Enable/Disable constellation",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1247,7 +1247,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Settings>
             /* .name          = */ "reserved_channels",
             /* .docs          = */ "Minimum number of channels reserved for this constellation",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved_channels>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved_channels>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1256,7 +1256,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Settings>
             /* .name          = */ "max_channels",
             /* .docs          = */ "Maximum number of channels to use for this constallation",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::max_channels>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::max_channels>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1265,7 +1265,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Settings>
             /* .name          = */ "option_flags",
             /* .docs          = */ "Constellation option Flags",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_3dm::ConstellationSettings::OptionFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::ConstellationSettings::OptionFlags, &type::option_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::ConstellationSettings::OptionFlags, &type::option_flags>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1290,7 +1290,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Response>
             /* .name          = */ "max_channels_available",
             /* .docs          = */ "Maximum channels available",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::max_channels_available>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::max_channels_available>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1299,7 +1299,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Response>
             /* .name          = */ "max_channels_use",
             /* .docs          = */ "Maximum channels to use",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::max_channels_use>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::max_channels_use>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1308,7 +1308,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Response>
             /* .name          = */ "config_count",
             /* .docs          = */ "Number of constellation configurations",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::config_count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::config_count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1317,7 +1317,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings::Response>
             /* .name          = */ "settings",
             /* .docs          = */ "Constellation Settings",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::ConstellationSettings::Settings>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::ConstellationSettings::Settings, &type::settings>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::ConstellationSettings::Settings, &type::settings>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {0, microstrain::Index(2) /* config_count */},
             /* .condition     = */ {},
@@ -1347,7 +1347,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings>
             /* .name          = */ "max_channels",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::max_channels>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::max_channels>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1356,7 +1356,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings>
             /* .name          = */ "config_count",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::config_count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::config_count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1365,7 +1365,7 @@ struct MetadataFor<commands_3dm::ConstellationSettings>
             /* .name          = */ "settings",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::ConstellationSettings::Settings>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::ConstellationSettings::Settings, &type::settings>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::ConstellationSettings::Settings, &type::settings>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {0, microstrain::Index(1) /* config_count */},
             /* .condition     = */ {},
@@ -1414,7 +1414,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings::Response>
             /* .name          = */ "enable_sbas",
             /* .docs          = */ "0 - SBAS Disabled, 1 - SBAS enabled",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable_sbas>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable_sbas>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1423,7 +1423,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings::Response>
             /* .name          = */ "sbas_options",
             /* .docs          = */ "SBAS options, see definition",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_3dm::GnssSbasSettings::SBASOptions>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GnssSbasSettings::SBASOptions, &type::sbas_options>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GnssSbasSettings::SBASOptions, &type::sbas_options>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1432,7 +1432,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings::Response>
             /* .name          = */ "num_included_prns",
             /* .docs          = */ "Number of SBAS PRNs to include in search (0 = include all)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_included_prns>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_included_prns>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1441,7 +1441,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings::Response>
             /* .name          = */ "included_prns",
             /* .docs          = */ "List of specific SBAS PRNs to search for",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::included_prns>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::included_prns>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {39, microstrain::Index(2) /* num_included_prns */},
             /* .condition     = */ {},
@@ -1471,7 +1471,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings>
             /* .name          = */ "enable_sbas",
             /* .docs          = */ "0 - SBAS Disabled, 1 - SBAS enabled",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable_sbas>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable_sbas>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1480,7 +1480,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings>
             /* .name          = */ "sbas_options",
             /* .docs          = */ "SBAS options, see definition",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_3dm::GnssSbasSettings::SBASOptions>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GnssSbasSettings::SBASOptions, &type::sbas_options>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GnssSbasSettings::SBASOptions, &type::sbas_options>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1489,7 +1489,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings>
             /* .name          = */ "num_included_prns",
             /* .docs          = */ "Number of SBAS PRNs to include in search (0 = include all)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_included_prns>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_included_prns>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1498,7 +1498,7 @@ struct MetadataFor<commands_3dm::GnssSbasSettings>
             /* .name          = */ "included_prns",
             /* .docs          = */ "List of specific SBAS PRNs to search for",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::included_prns>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::included_prns>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {39, microstrain::Index(2) /* num_included_prns */},
             /* .condition     = */ {},
@@ -1546,7 +1546,7 @@ struct MetadataFor<commands_3dm::GnssAssistedFix::Response>
             /* .name          = */ "option",
             /* .docs          = */ "Assisted fix options",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GnssAssistedFix::AssistedFixOption>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GnssAssistedFix::AssistedFixOption, &type::option>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GnssAssistedFix::AssistedFixOption, &type::option>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1555,7 +1555,7 @@ struct MetadataFor<commands_3dm::GnssAssistedFix::Response>
             /* .name          = */ "flags",
             /* .docs          = */ "Assisted fix flags (set to 0xFF)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1585,7 +1585,7 @@ struct MetadataFor<commands_3dm::GnssAssistedFix>
             /* .name          = */ "option",
             /* .docs          = */ "Assisted fix options",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GnssAssistedFix::AssistedFixOption>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GnssAssistedFix::AssistedFixOption, &type::option>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GnssAssistedFix::AssistedFixOption, &type::option>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1594,7 +1594,7 @@ struct MetadataFor<commands_3dm::GnssAssistedFix>
             /* .name          = */ "flags",
             /* .docs          = */ "Assisted fix flags (set to 0xFF)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1623,7 +1623,7 @@ struct MetadataFor<commands_3dm::GnssTimeAssistance::Response>
             /* .name          = */ "tow",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tow>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tow>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1632,7 +1632,7 @@ struct MetadataFor<commands_3dm::GnssTimeAssistance::Response>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Weeks since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1641,7 +1641,7 @@ struct MetadataFor<commands_3dm::GnssTimeAssistance::Response>
             /* .name          = */ "accuracy",
             /* .docs          = */ "Accuracy of time information [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1671,7 +1671,7 @@ struct MetadataFor<commands_3dm::GnssTimeAssistance>
             /* .name          = */ "tow",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tow>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tow>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1680,7 +1680,7 @@ struct MetadataFor<commands_3dm::GnssTimeAssistance>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Weeks since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1689,7 +1689,7 @@ struct MetadataFor<commands_3dm::GnssTimeAssistance>
             /* .name          = */ "accuracy",
             /* .docs          = */ "Accuracy of time information [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1718,7 +1718,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter::Response>
             /* .name          = */ "target_descriptor",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::target_descriptor>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::target_descriptor>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1727,7 +1727,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "True if the filter is currently enabled.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1736,7 +1736,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter::Response>
             /* .name          = */ "manual",
             /* .docs          = */ "True if the filter cutoff was manually configured.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::manual>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::manual>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1745,7 +1745,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter::Response>
             /* .name          = */ "frequency",
             /* .docs          = */ "The cutoff frequency of the filter. If the filter is in\nauto mode, this value is unspecified.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1754,7 +1754,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter::Response>
             /* .name          = */ "reserved",
             /* .docs          = */ "Reserved and must be ignored.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1784,7 +1784,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter>
             /* .name          = */ "target_descriptor",
             /* .docs          = */ "Field descriptor of filtered quantity within the Sensor data set.\nSupported values are accel (0x04), gyro (0x05), mag (0x06), and\npressure (0x17), provided the data is supported by the device.\nExcept with the READ function selector, this can be 0 to apply to all of the above quantities.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::target_descriptor>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::target_descriptor>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1793,7 +1793,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter>
             /* .name          = */ "enable",
             /* .docs          = */ "The target data will be filtered if this is true.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1802,7 +1802,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter>
             /* .name          = */ "manual",
             /* .docs          = */ "If false, the cutoff frequency is set to half of the\nstreaming rate as configured by the message format command.\nOtherwise, the cutoff frequency is set according to the\nfollowing 'frequency' parameter.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::manual>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::manual>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1811,7 +1811,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter>
             /* .name          = */ "frequency",
             /* .docs          = */ "-3dB cutoff frequency in Hz. Will not affect filtering if 'manual' is false.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1820,7 +1820,7 @@ struct MetadataFor<commands_3dm::ImuLowpassFilter>
             /* .name          = */ "reserved",
             /* .docs          = */ "Reserved, set to 0x00.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1871,7 +1871,7 @@ struct MetadataFor<commands_3dm::PpsSource::Response>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::PpsSource::Source>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::PpsSource::Source, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::PpsSource::Source, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1901,7 +1901,7 @@ struct MetadataFor<commands_3dm::PpsSource>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::PpsSource::Source>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::PpsSource::Source, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::PpsSource::Source, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2005,7 +2005,7 @@ struct MetadataFor<commands_3dm::GpioConfig::Response>
             /* .name          = */ "pin",
             /* .docs          = */ "GPIO pin number counting from 1. For save, load, and default function selectors, this can be 0 to select all pins.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::pin>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::pin>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2014,7 +2014,7 @@ struct MetadataFor<commands_3dm::GpioConfig::Response>
             /* .name          = */ "feature",
             /* .docs          = */ "Determines how the pin will be used.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GpioConfig::Feature>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GpioConfig::Feature, &type::feature>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GpioConfig::Feature, &type::feature>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2023,7 +2023,7 @@ struct MetadataFor<commands_3dm::GpioConfig::Response>
             /* .name          = */ "behavior",
             /* .docs          = */ "Select an appropriate value from the enumeration based on the selected feature (e.g. for PPS, select one of the values prefixed with PPS_.)",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GpioConfig::Behavior>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GpioConfig::Behavior, &type::behavior>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GpioConfig::Behavior, &type::behavior>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2032,7 +2032,7 @@ struct MetadataFor<commands_3dm::GpioConfig::Response>
             /* .name          = */ "pin_mode",
             /* .docs          = */ "GPIO configuration. May be restricted depending on device, pin, feature, and behavior. See device user manual.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_3dm::GpioConfig::PinMode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GpioConfig::PinMode, &type::pin_mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GpioConfig::PinMode, &type::pin_mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2062,7 +2062,7 @@ struct MetadataFor<commands_3dm::GpioConfig>
             /* .name          = */ "pin",
             /* .docs          = */ "GPIO pin number counting from 1. For save, load, and default function selectors, this can be 0 to select all pins.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::pin>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::pin>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2071,7 +2071,7 @@ struct MetadataFor<commands_3dm::GpioConfig>
             /* .name          = */ "feature",
             /* .docs          = */ "Determines how the pin will be used.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GpioConfig::Feature>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GpioConfig::Feature, &type::feature>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GpioConfig::Feature, &type::feature>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2080,7 +2080,7 @@ struct MetadataFor<commands_3dm::GpioConfig>
             /* .name          = */ "behavior",
             /* .docs          = */ "Select an appropriate value from the enumeration based on the selected feature (e.g. for PPS, select one of the values prefixed with PPS_.)",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GpioConfig::Behavior>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GpioConfig::Behavior, &type::behavior>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GpioConfig::Behavior, &type::behavior>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2089,7 +2089,7 @@ struct MetadataFor<commands_3dm::GpioConfig>
             /* .name          = */ "pin_mode",
             /* .docs          = */ "GPIO configuration. May be restricted depending on device, pin, feature, and behavior. See device user manual.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_3dm::GpioConfig::PinMode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GpioConfig::PinMode, &type::pin_mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GpioConfig::PinMode, &type::pin_mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2118,7 +2118,7 @@ struct MetadataFor<commands_3dm::GpioState::Response>
             /* .name          = */ "pin",
             /* .docs          = */ "GPIO pin number counting from 1. Cannot be 0.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::pin>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::pin>,
             /* .attributes    = */ {true, true, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2127,7 +2127,7 @@ struct MetadataFor<commands_3dm::GpioState::Response>
             /* .name          = */ "state",
             /* .docs          = */ "The pin state.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::state>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2157,7 +2157,7 @@ struct MetadataFor<commands_3dm::GpioState>
             /* .name          = */ "pin",
             /* .docs          = */ "GPIO pin number counting from 1. Cannot be 0.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::pin>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::pin>,
             /* .attributes    = */ {true, true, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2166,7 +2166,7 @@ struct MetadataFor<commands_3dm::GpioState>
             /* .name          = */ "state",
             /* .docs          = */ "The pin state.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::state>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2214,7 +2214,7 @@ struct MetadataFor<commands_3dm::Odometer::Response>
             /* .name          = */ "mode",
             /* .docs          = */ "Mode setting.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::Odometer::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::Odometer::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::Odometer::Mode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2223,7 +2223,7 @@ struct MetadataFor<commands_3dm::Odometer::Response>
             /* .name          = */ "scaling",
             /* .docs          = */ "Encoder pulses per meter of distance traveled [pulses/m].\nDistance traveled is computed using the formula d = p / N * 2R * pi, where d is distance,\np is the number of pulses received, N is the encoder resolution, and R is the wheel radius.\nBy simplifying all of the parameters into one, the formula d = p / S is obtained, where s\nis the odometer scaling factor passed to this command. S is equivalent to N / (2R * pi) and\nhas units of pulses / meter. N is in units of 'A' pulses per revolution and R is in meters.\nMake this value negative if the odometer is mounted so that it rotates backwards.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::scaling>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::scaling>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2232,7 +2232,7 @@ struct MetadataFor<commands_3dm::Odometer::Response>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "Uncertainty in encoder counts to distance translation (1-sigma value) [m/m].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2262,7 +2262,7 @@ struct MetadataFor<commands_3dm::Odometer>
             /* .name          = */ "mode",
             /* .docs          = */ "Mode setting.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::Odometer::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::Odometer::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::Odometer::Mode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2271,7 +2271,7 @@ struct MetadataFor<commands_3dm::Odometer>
             /* .name          = */ "scaling",
             /* .docs          = */ "Encoder pulses per meter of distance traveled [pulses/m].\nDistance traveled is computed using the formula d = p / N * 2R * pi, where d is distance,\np is the number of pulses received, N is the encoder resolution, and R is the wheel radius.\nBy simplifying all of the parameters into one, the formula d = p / S is obtained, where s\nis the odometer scaling factor passed to this command. S is equivalent to N / (2R * pi) and\nhas units of pulses / meter. N is in units of 'A' pulses per revolution and R is in meters.\nMake this value negative if the odometer is mounted so that it rotates backwards.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::scaling>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::scaling>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2280,7 +2280,7 @@ struct MetadataFor<commands_3dm::Odometer>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "Uncertainty in encoder counts to distance translation (1-sigma value) [m/m].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2328,7 +2328,7 @@ struct MetadataFor<commands_3dm::GetEventSupport::Info>
             /* .name          = */ "type",
             /* .docs          = */ "Trigger or action type, as defined in the respective setup command.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::type>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2337,7 +2337,7 @@ struct MetadataFor<commands_3dm::GetEventSupport::Info>
             /* .name          = */ "count",
             /* .docs          = */ "This is the maximum number of instances supported for this type.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2362,7 +2362,7 @@ struct MetadataFor<commands_3dm::GetEventSupport::Response>
             /* .name          = */ "query",
             /* .docs          = */ "Query type specified in the command.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GetEventSupport::Query>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GetEventSupport::Query, &type::query>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GetEventSupport::Query, &type::query>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2371,7 +2371,7 @@ struct MetadataFor<commands_3dm::GetEventSupport::Response>
             /* .name          = */ "max_instances",
             /* .docs          = */ "Number of slots available. The 'instance' number for\nthe configuration or control commands must be between 1 and this value.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::max_instances>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::max_instances>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2380,7 +2380,7 @@ struct MetadataFor<commands_3dm::GetEventSupport::Response>
             /* .name          = */ "num_entries",
             /* .docs          = */ "Number of supported types.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_entries>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_entries>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2389,7 +2389,7 @@ struct MetadataFor<commands_3dm::GetEventSupport::Response>
             /* .name          = */ "entries",
             /* .docs          = */ "List of supported types.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::GetEventSupport::Info>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GetEventSupport::Info, &type::entries>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GetEventSupport::Info, &type::entries>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {0, microstrain::Index(2) /* num_entries */},
             /* .condition     = */ {},
@@ -2418,7 +2418,7 @@ struct MetadataFor<commands_3dm::GetEventSupport>
             /* .name          = */ "query",
             /* .docs          = */ "What type of information to retrieve.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::GetEventSupport::Query>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GetEventSupport::Query, &type::query>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GetEventSupport::Query, &type::query>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2468,7 +2468,7 @@ struct MetadataFor<commands_3dm::EventControl::Response>
             /* .name          = */ "instance",
             /* .docs          = */ "Trigger instance to affect. 0 can be used to apply the mode to all\nconfigured triggers, except when the function selector is READ.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::instance>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::instance>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2477,7 +2477,7 @@ struct MetadataFor<commands_3dm::EventControl::Response>
             /* .name          = */ "mode",
             /* .docs          = */ "How to change the trigger state. Except when instance is 0, the\ncorresponding trigger must be configured, i.e. not have type 0.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventControl::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventControl::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventControl::Mode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2507,7 +2507,7 @@ struct MetadataFor<commands_3dm::EventControl>
             /* .name          = */ "instance",
             /* .docs          = */ "Trigger instance to affect. 0 can be used to apply the mode to all\nconfigured triggers, except when the function selector is READ.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::instance>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::instance>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2516,7 +2516,7 @@ struct MetadataFor<commands_3dm::EventControl>
             /* .name          = */ "mode",
             /* .docs          = */ "How to change the trigger state. Except when instance is 0, the\ncorresponding trigger must be configured, i.e. not have type 0.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventControl::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventControl::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventControl::Mode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2565,7 +2565,7 @@ struct MetadataFor<commands_3dm::GetEventTriggerStatus::Entry>
             /* .name          = */ "type",
             /* .docs          = */ "Configured trigger type.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::type>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2574,7 +2574,7 @@ struct MetadataFor<commands_3dm::GetEventTriggerStatus::Entry>
             /* .name          = */ "status",
             /* .docs          = */ "Trigger status.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_3dm::GetEventTriggerStatus::Status>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GetEventTriggerStatus::Status, &type::status>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GetEventTriggerStatus::Status, &type::status>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2599,7 +2599,7 @@ struct MetadataFor<commands_3dm::GetEventTriggerStatus::Response>
             /* .name          = */ "count",
             /* .docs          = */ "Number of entries requested. If requested_count was 0, this is the number of supported trigger slots.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2608,7 +2608,7 @@ struct MetadataFor<commands_3dm::GetEventTriggerStatus::Response>
             /* .name          = */ "triggers",
             /* .docs          = */ "A list of the configured triggers. Entries are in the order requested, or in increasing order if count was 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::GetEventTriggerStatus::Entry>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GetEventTriggerStatus::Entry, &type::triggers>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GetEventTriggerStatus::Entry, &type::triggers>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {20, microstrain::Index(0) /* count */},
             /* .condition     = */ {},
@@ -2637,7 +2637,7 @@ struct MetadataFor<commands_3dm::GetEventTriggerStatus>
             /* .name          = */ "requested_count",
             /* .docs          = */ "Number of entries requested. If 0, requests all trigger slots.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::requested_count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::requested_count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2646,7 +2646,7 @@ struct MetadataFor<commands_3dm::GetEventTriggerStatus>
             /* .name          = */ "requested_instances",
             /* .docs          = */ "List of trigger instances to query.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::requested_instances>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::requested_instances>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {20, microstrain::Index(0) /* requested_count */},
             /* .condition     = */ {},
@@ -2675,7 +2675,7 @@ struct MetadataFor<commands_3dm::GetEventActionStatus::Entry>
             /* .name          = */ "action_type",
             /* .docs          = */ "Configured action type.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::action_type>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::action_type>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2684,7 +2684,7 @@ struct MetadataFor<commands_3dm::GetEventActionStatus::Entry>
             /* .name          = */ "trigger_id",
             /* .docs          = */ "Associated trigger instance.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::trigger_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::trigger_id>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2709,7 +2709,7 @@ struct MetadataFor<commands_3dm::GetEventActionStatus::Response>
             /* .name          = */ "count",
             /* .docs          = */ "Number of entries requested. If requested_count was 0, this is the number of supported action slots.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2718,7 +2718,7 @@ struct MetadataFor<commands_3dm::GetEventActionStatus::Response>
             /* .name          = */ "actions",
             /* .docs          = */ "A list of the configured actions. Entries are in the order requested, or in increasing order if count was 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::GetEventActionStatus::Entry>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::GetEventActionStatus::Entry, &type::actions>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::GetEventActionStatus::Entry, &type::actions>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {20, microstrain::Index(0) /* count */},
             /* .condition     = */ {},
@@ -2747,7 +2747,7 @@ struct MetadataFor<commands_3dm::GetEventActionStatus>
             /* .name          = */ "requested_count",
             /* .docs          = */ "Number of entries requested. If 0, requests all action slots.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::requested_count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::requested_count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2756,7 +2756,7 @@ struct MetadataFor<commands_3dm::GetEventActionStatus>
             /* .name          = */ "requested_instances",
             /* .docs          = */ "List of action instances to query.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::requested_instances>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::requested_instances>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {20, microstrain::Index(0) /* requested_count */},
             /* .condition     = */ {},
@@ -2806,7 +2806,7 @@ struct MetadataFor<commands_3dm::EventTrigger::GpioParams>
             /* .name          = */ "pin",
             /* .docs          = */ "GPIO pin number.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::pin>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::pin>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2815,7 +2815,7 @@ struct MetadataFor<commands_3dm::EventTrigger::GpioParams>
             /* .name          = */ "mode",
             /* .docs          = */ "How the pin state affects the trigger.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventTrigger::GpioParams::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::GpioParams::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::GpioParams::Mode, &type::mode>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2859,7 +2859,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Descriptor set of target data quantity.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2868,7 +2868,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "field_desc",
             /* .docs          = */ "Field descriptor of target data quantity.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::field_desc>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::field_desc>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2877,7 +2877,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "param_id",
             /* .docs          = */ "1-based index of the target parameter within the MIP field. E.g. for Scaled Accel (0x80,0x04) a value of 2 would represent the Y axis.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::param_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::param_id>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2886,7 +2886,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "type",
             /* .docs          = */ "Determines the type of comparison.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventTrigger::ThresholdParams::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::ThresholdParams::Type, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::ThresholdParams::Type, &type::type>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2895,7 +2895,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "low_thres",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::low_thres>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::low_thres>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(3) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::ThresholdParams::Type::WINDOW)} /* type == WINDOW */,
@@ -2904,7 +2904,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "int_thres",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::int_thres>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::int_thres>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(3) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::ThresholdParams::Type::INTERVAL)} /* type == INTERVAL */,
@@ -2913,7 +2913,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "high_thres",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::high_thres>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::high_thres>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(3) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::ThresholdParams::Type::WINDOW)} /* type == WINDOW */,
@@ -2922,7 +2922,7 @@ struct MetadataFor<commands_3dm::EventTrigger::ThresholdParams>
             /* .name          = */ "interval",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::interval>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::interval>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(3) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::ThresholdParams::Type::INTERVAL)} /* type == INTERVAL */,
@@ -2947,7 +2947,7 @@ struct MetadataFor<commands_3dm::EventTrigger::CombinationParams>
             /* .name          = */ "logic_table",
             /* .docs          = */ "The last column of a truth table describing the output given the state of each input.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::logic_table>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::logic_table>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2956,7 +2956,7 @@ struct MetadataFor<commands_3dm::EventTrigger::CombinationParams>
             /* .name          = */ "input_triggers",
             /* .docs          = */ "List of trigger IDs for inputs. Use 0 for unused inputs.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::input_triggers>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::input_triggers>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -3002,7 +3002,7 @@ struct MetadataFor<commands_3dm::EventTrigger::Parameters>
             /* .name          = */ "gpio",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::EventTrigger::GpioParams>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::GpioParams, &type::gpio>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::GpioParams, &type::gpio>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(1) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::Type::GPIO)} /* type == GPIO */,
@@ -3011,7 +3011,7 @@ struct MetadataFor<commands_3dm::EventTrigger::Parameters>
             /* .name          = */ "threshold",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::EventTrigger::ThresholdParams>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::ThresholdParams, &type::threshold>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::ThresholdParams, &type::threshold>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(1) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::Type::THRESHOLD)} /* type == THRESHOLD */,
@@ -3020,7 +3020,7 @@ struct MetadataFor<commands_3dm::EventTrigger::Parameters>
             /* .name          = */ "combination",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::EventTrigger::CombinationParams>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::CombinationParams, &type::combination>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::CombinationParams, &type::combination>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(1) /* type */, static_cast<uint16_t>(commands_3dm::EventTrigger::Type::COMBINATION)} /* type == COMBINATION */,
@@ -3045,7 +3045,7 @@ struct MetadataFor<commands_3dm::EventTrigger::Response>
             /* .name          = */ "instance",
             /* .docs          = */ "Trigger number. When function is SAVE, LOAD, or DEFAULT, this can be 0 to apply to all instances.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::instance>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::instance>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3054,7 +3054,7 @@ struct MetadataFor<commands_3dm::EventTrigger::Response>
             /* .name          = */ "type",
             /* .docs          = */ "Type of trigger to configure.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventTrigger::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::Type, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::Type, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3063,7 +3063,7 @@ struct MetadataFor<commands_3dm::EventTrigger::Response>
             /* .name          = */ "parameters",
             /* .docs          = */ "",
             /* .type          = */ {Type::UNION, &MetadataFor<commands_3dm::EventTrigger::Parameters>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::Parameters, &type::parameters>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::Parameters, &type::parameters>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3093,7 +3093,7 @@ struct MetadataFor<commands_3dm::EventTrigger>
             /* .name          = */ "instance",
             /* .docs          = */ "Trigger number. When function is SAVE, LOAD, or DEFAULT, this can be 0 to apply to all instances.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::instance>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::instance>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3102,7 +3102,7 @@ struct MetadataFor<commands_3dm::EventTrigger>
             /* .name          = */ "type",
             /* .docs          = */ "Type of trigger to configure.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventTrigger::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::Type, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::Type, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3111,7 +3111,7 @@ struct MetadataFor<commands_3dm::EventTrigger>
             /* .name          = */ "parameters",
             /* .docs          = */ "",
             /* .type          = */ {Type::UNION, &MetadataFor<commands_3dm::EventTrigger::Parameters>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventTrigger::Parameters, &type::parameters>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventTrigger::Parameters, &type::parameters>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3163,7 +3163,7 @@ struct MetadataFor<commands_3dm::EventAction::GpioParams>
             /* .name          = */ "pin",
             /* .docs          = */ "GPIO pin number.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::pin>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::pin>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3172,7 +3172,7 @@ struct MetadataFor<commands_3dm::EventAction::GpioParams>
             /* .name          = */ "mode",
             /* .docs          = */ "Behavior of the pin.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventAction::GpioParams::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::GpioParams::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::GpioParams::Mode, &type::mode>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3197,7 +3197,7 @@ struct MetadataFor<commands_3dm::EventAction::MessageParams>
             /* .name          = */ "desc_set",
             /* .docs          = */ "MIP data descriptor set.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3206,7 +3206,7 @@ struct MetadataFor<commands_3dm::EventAction::MessageParams>
             /* .name          = */ "decimation",
             /* .docs          = */ "Decimation from the base rate.\nIf 0, a packet is emitted each time the trigger activates.\nOtherwise, packets will be streamed while the trigger is active.\nThe internal decimation counter is reset if the trigger deactivates.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::decimation>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::decimation>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3215,7 +3215,7 @@ struct MetadataFor<commands_3dm::EventAction::MessageParams>
             /* .name          = */ "num_fields",
             /* .docs          = */ "Number of mip fields in the packet. Limited to 12.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_fields>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_fields>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3224,7 +3224,7 @@ struct MetadataFor<commands_3dm::EventAction::MessageParams>
             /* .name          = */ "descriptors",
             /* .docs          = */ "List of field descriptors.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::descriptors>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ {20, microstrain::Index(2) /* num_fields */},
             /* .condition     = */ {},
@@ -3269,7 +3269,7 @@ struct MetadataFor<commands_3dm::EventAction::Parameters>
             /* .name          = */ "gpio",
             /* .docs          = */ "Gpio parameters, if type == GPIO. Ignore otherwise.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::EventAction::GpioParams>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::GpioParams, &type::gpio>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::GpioParams, &type::gpio>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(2) /* type */, static_cast<uint16_t>(commands_3dm::EventAction::Type::GPIO)} /* type == GPIO */,
@@ -3278,7 +3278,7 @@ struct MetadataFor<commands_3dm::EventAction::Parameters>
             /* .name          = */ "message",
             /* .docs          = */ "Message parameters, if type == MESSAGE. Ignore otherwise.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::EventAction::MessageParams>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::MessageParams, &type::message>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::MessageParams, &type::message>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(2) /* type */, static_cast<uint16_t>(commands_3dm::EventAction::Type::MESSAGE)} /* type == MESSAGE */,
@@ -3303,7 +3303,7 @@ struct MetadataFor<commands_3dm::EventAction::Response>
             /* .name          = */ "instance",
             /* .docs          = */ "Action number. When function is SAVE, LOAD, or DEFAULT, this can be 0 to apply to all instances.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::instance>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::instance>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3312,7 +3312,7 @@ struct MetadataFor<commands_3dm::EventAction::Response>
             /* .name          = */ "trigger",
             /* .docs          = */ "Trigger ID number.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::trigger>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::trigger>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3321,7 +3321,7 @@ struct MetadataFor<commands_3dm::EventAction::Response>
             /* .name          = */ "type",
             /* .docs          = */ "Type of action to configure.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventAction::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::Type, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::Type, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3330,7 +3330,7 @@ struct MetadataFor<commands_3dm::EventAction::Response>
             /* .name          = */ "parameters",
             /* .docs          = */ "",
             /* .type          = */ {Type::UNION, &MetadataFor<commands_3dm::EventAction::Parameters>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::Parameters, &type::parameters>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::Parameters, &type::parameters>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3360,7 +3360,7 @@ struct MetadataFor<commands_3dm::EventAction>
             /* .name          = */ "instance",
             /* .docs          = */ "Action number. When function is SAVE, LOAD, or DEFAULT, this can be 0 to apply to all instances.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::instance>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::instance>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3369,7 +3369,7 @@ struct MetadataFor<commands_3dm::EventAction>
             /* .name          = */ "trigger",
             /* .docs          = */ "Trigger ID number.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::trigger>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::trigger>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3378,7 +3378,7 @@ struct MetadataFor<commands_3dm::EventAction>
             /* .name          = */ "type",
             /* .docs          = */ "Type of action to configure.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::EventAction::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::Type, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::Type, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3387,7 +3387,7 @@ struct MetadataFor<commands_3dm::EventAction>
             /* .name          = */ "parameters",
             /* .docs          = */ "",
             /* .type          = */ {Type::UNION, &MetadataFor<commands_3dm::EventAction::Parameters>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::EventAction::Parameters, &type::parameters>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::EventAction::Parameters, &type::parameters>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3416,7 +3416,7 @@ struct MetadataFor<commands_3dm::AccelBias::Response>
             /* .name          = */ "bias",
             /* .docs          = */ "accelerometer bias in the sensor frame (x,y,z) [g]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3446,7 +3446,7 @@ struct MetadataFor<commands_3dm::AccelBias>
             /* .name          = */ "bias",
             /* .docs          = */ "accelerometer bias in the sensor frame (x,y,z) [g]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3475,7 +3475,7 @@ struct MetadataFor<commands_3dm::GyroBias::Response>
             /* .name          = */ "bias",
             /* .docs          = */ "gyro bias in the sensor frame (x,y,z) [radians/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3505,7 +3505,7 @@ struct MetadataFor<commands_3dm::GyroBias>
             /* .name          = */ "bias",
             /* .docs          = */ "gyro bias in the sensor frame (x,y,z) [radians/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3534,7 +3534,7 @@ struct MetadataFor<commands_3dm::CaptureGyroBias::Response>
             /* .name          = */ "bias",
             /* .docs          = */ "gyro bias in the sensor frame (x,y,z) [radians/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3563,7 +3563,7 @@ struct MetadataFor<commands_3dm::CaptureGyroBias>
             /* .name          = */ "averaging_time_ms",
             /* .docs          = */ "Averaging time [milliseconds]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::averaging_time_ms>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::averaging_time_ms>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3592,7 +3592,7 @@ struct MetadataFor<commands_3dm::MagHardIronOffset::Response>
             /* .name          = */ "offset",
             /* .docs          = */ "hard iron offset in the sensor frame (x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3622,7 +3622,7 @@ struct MetadataFor<commands_3dm::MagHardIronOffset>
             /* .name          = */ "offset",
             /* .docs          = */ "hard iron offset in the sensor frame (x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3651,7 +3651,7 @@ struct MetadataFor<commands_3dm::MagSoftIronMatrix::Response>
             /* .name          = */ "offset",
             /* .docs          = */ "soft iron matrix [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3681,7 +3681,7 @@ struct MetadataFor<commands_3dm::MagSoftIronMatrix>
             /* .name          = */ "offset",
             /* .docs          = */ "soft iron matrix [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3710,7 +3710,7 @@ struct MetadataFor<commands_3dm::ConingScullingEnable::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "If true, coning and sculling compensation is enabled.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3740,7 +3740,7 @@ struct MetadataFor<commands_3dm::ConingScullingEnable>
             /* .name          = */ "enable",
             /* .docs          = */ "If true, coning and sculling compensation is enabled.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3769,7 +3769,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformEuler::Response>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3778,7 +3778,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformEuler::Response>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3787,7 +3787,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformEuler::Response>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3817,7 +3817,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformEuler>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3826,7 +3826,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformEuler>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3835,7 +3835,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformEuler>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3864,7 +3864,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformQuaternion::Response>
             /* .name          = */ "q",
             /* .docs          = */ "Unit length quaternion representing transform [w, i, j, k]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::q>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::q>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3894,7 +3894,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformQuaternion>
             /* .name          = */ "q",
             /* .docs          = */ "Unit length quaternion representing transform [w, i, j, k]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::q>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::q>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3923,7 +3923,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformDcm::Response>
             /* .name          = */ "dcm",
             /* .docs          = */ "3 x 3 direction cosine matrix, stored in row-major order",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::dcm>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::dcm>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3953,7 +3953,7 @@ struct MetadataFor<commands_3dm::Sensor2VehicleTransformDcm>
             /* .name          = */ "dcm",
             /* .docs          = */ "3 x 3 direction cosine matrix, stored in row-major order",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::dcm>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::dcm>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3982,7 +3982,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter::Response>
             /* .name          = */ "pitch_roll_enable",
             /* .docs          = */ "Enable Pitch/Roll corrections",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::pitch_roll_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::pitch_roll_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3991,7 +3991,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter::Response>
             /* .name          = */ "heading_enable",
             /* .docs          = */ "Enable Heading corrections (only available on devices with magnetometer)",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::heading_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::heading_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4000,7 +4000,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter::Response>
             /* .name          = */ "pitch_roll_time_constant",
             /* .docs          = */ "Time constant associated with the pitch/roll corrections [s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch_roll_time_constant>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch_roll_time_constant>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4009,7 +4009,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter::Response>
             /* .name          = */ "heading_time_constant",
             /* .docs          = */ "Time constant associated with the heading corrections [s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_time_constant>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_time_constant>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4039,7 +4039,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter>
             /* .name          = */ "pitch_roll_enable",
             /* .docs          = */ "Enable Pitch/Roll corrections",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::pitch_roll_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::pitch_roll_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4048,7 +4048,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter>
             /* .name          = */ "heading_enable",
             /* .docs          = */ "Enable Heading corrections (only available on devices with magnetometer)",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::heading_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::heading_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4057,7 +4057,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter>
             /* .name          = */ "pitch_roll_time_constant",
             /* .docs          = */ "Time constant associated with the pitch/roll corrections [s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch_roll_time_constant>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch_roll_time_constant>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4066,7 +4066,7 @@ struct MetadataFor<commands_3dm::ComplementaryFilter>
             /* .name          = */ "heading_time_constant",
             /* .docs          = */ "Time constant associated with the heading corrections [s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_time_constant>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_time_constant>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4117,7 +4117,7 @@ struct MetadataFor<commands_3dm::SensorRange::Response>
             /* .name          = */ "sensor",
             /* .docs          = */ "Which type of sensor will get the new range value.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::SensorRangeType>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4126,7 +4126,7 @@ struct MetadataFor<commands_3dm::SensorRange::Response>
             /* .name          = */ "setting",
             /* .docs          = */ "Use the 3DM Get Calibrated Sensor Ranges (0x0C,0x53) command to determine this value.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::setting>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::setting>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4156,7 +4156,7 @@ struct MetadataFor<commands_3dm::SensorRange>
             /* .name          = */ "sensor",
             /* .docs          = */ "Which type of sensor will get the new range value.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::SensorRangeType>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4165,7 +4165,7 @@ struct MetadataFor<commands_3dm::SensorRange>
             /* .name          = */ "setting",
             /* .docs          = */ "Use the 3DM Get Calibrated Sensor Ranges (0x0C,0x53) command to determine this value.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::setting>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::setting>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4194,7 +4194,7 @@ struct MetadataFor<commands_3dm::CalibratedSensorRanges::Entry>
             /* .name          = */ "setting",
             /* .docs          = */ "The value used in the 3DM Sensor Range command and response.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::setting>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::setting>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4203,7 +4203,7 @@ struct MetadataFor<commands_3dm::CalibratedSensorRanges::Entry>
             /* .name          = */ "range",
             /* .docs          = */ "The actual range value. Units depend on the sensor type.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::range>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::range>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4228,7 +4228,7 @@ struct MetadataFor<commands_3dm::CalibratedSensorRanges::Response>
             /* .name          = */ "sensor",
             /* .docs          = */ "The sensor type from the command.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::SensorRangeType>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4237,7 +4237,7 @@ struct MetadataFor<commands_3dm::CalibratedSensorRanges::Response>
             /* .name          = */ "num_ranges",
             /* .docs          = */ "Number of supported ranges.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_ranges>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_ranges>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4246,7 +4246,7 @@ struct MetadataFor<commands_3dm::CalibratedSensorRanges::Response>
             /* .name          = */ "ranges",
             /* .docs          = */ "List of possible range settings.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_3dm::CalibratedSensorRanges::Entry>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::CalibratedSensorRanges::Entry, &type::ranges>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::CalibratedSensorRanges::Entry, &type::ranges>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {0, microstrain::Index(1) /* num_ranges */},
             /* .condition     = */ {},
@@ -4275,7 +4275,7 @@ struct MetadataFor<commands_3dm::CalibratedSensorRanges>
             /* .name          = */ "sensor",
             /* .docs          = */ "The sensor to query. Cannot be ALL.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_3dm::SensorRangeType>::value},
-            /* .accessor      = */ utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_3dm::SensorRangeType, &type::sensor>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4304,7 +4304,7 @@ struct MetadataFor<commands_3dm::LowpassFilter::Response>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Descriptor set of the quantity to be filtered.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4313,7 +4313,7 @@ struct MetadataFor<commands_3dm::LowpassFilter::Response>
             /* .name          = */ "field_desc",
             /* .docs          = */ "Field descriptor of the quantity to be filtered.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::field_desc>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::field_desc>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4322,7 +4322,7 @@ struct MetadataFor<commands_3dm::LowpassFilter::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "The filter will be enabled if this is true.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4331,7 +4331,7 @@ struct MetadataFor<commands_3dm::LowpassFilter::Response>
             /* .name          = */ "manual",
             /* .docs          = */ "If false, the frequency parameter is ignored and the filter\nwill track to half of the configured message format frequency.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::manual>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::manual>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4340,7 +4340,7 @@ struct MetadataFor<commands_3dm::LowpassFilter::Response>
             /* .name          = */ "frequency",
             /* .docs          = */ "Cutoff frequency in Hz. This will return the actual frequency\nwhen read out in automatic mode.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4370,7 +4370,7 @@ struct MetadataFor<commands_3dm::LowpassFilter>
             /* .name          = */ "desc_set",
             /* .docs          = */ "Descriptor set of the quantity to be filtered.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::desc_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::desc_set>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4379,7 +4379,7 @@ struct MetadataFor<commands_3dm::LowpassFilter>
             /* .name          = */ "field_desc",
             /* .docs          = */ "Field descriptor of the quantity to be filtered.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::field_desc>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::field_desc>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4388,7 +4388,7 @@ struct MetadataFor<commands_3dm::LowpassFilter>
             /* .name          = */ "enable",
             /* .docs          = */ "The filter will be enabled if this is true.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4397,7 +4397,7 @@ struct MetadataFor<commands_3dm::LowpassFilter>
             /* .name          = */ "manual",
             /* .docs          = */ "If false, the frequency parameter is ignored and the filter\nwill track to half of the configured message format frequency.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::manual>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::manual>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4406,7 +4406,7 @@ struct MetadataFor<commands_3dm::LowpassFilter>
             /* .name          = */ "frequency",
             /* .docs          = */ "Cutoff frequency in Hz. This will return the actual frequency\nwhen read out in automatic mode.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/commands_aiding.hpp b/src/cpp/mip/metadata/definitions/commands_aiding.hpp
index 5b15d17b..474f72ee 100644
--- a/src/cpp/mip/metadata/definitions/commands_aiding.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_aiding.hpp
@@ -39,7 +39,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Rotation>
             /* .name          = */ "euler",
             /* .docs          = */ "Rotation represented as euler angles in RPY format [rad]. Range +/- pi.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::euler>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::euler>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(1) /* format */, static_cast<uint16_t>(commands_aiding::FrameConfig::Format::EULER)} /* format == EULER */,
@@ -48,7 +48,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Rotation>
             /* .name          = */ "quaternion",
             /* .docs          = */ "Rotation represented as a quaternion in WXYZ format.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::quaternion>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::quaternion>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {ParameterInfo::Condition::Type::ENUM, microstrain::Index(1) /* format */, static_cast<uint16_t>(commands_aiding::FrameConfig::Format::QUATERNION)} /* format == QUATERNION */,
@@ -73,7 +73,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Response>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Reference frame number. Limit 4.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -82,7 +82,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Response>
             /* .name          = */ "format",
             /* .docs          = */ "Format of the transformation.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_aiding::FrameConfig::Format>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::FrameConfig::Format, &type::format>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::FrameConfig::Format, &type::format>,
             /* .attributes    = */ {true, true, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -91,7 +91,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Response>
             /* .name          = */ "tracking_enabled",
             /* .docs          = */ "If enabled, the Kalman filter will track errors.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::tracking_enabled>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::tracking_enabled>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -100,7 +100,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Response>
             /* .name          = */ "translation",
             /* .docs          = */ "Translation X, Y, and Z.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::translation>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::translation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -109,7 +109,7 @@ struct MetadataFor<commands_aiding::FrameConfig::Response>
             /* .name          = */ "rotation",
             /* .docs          = */ "Rotation as specified by format.",
             /* .type          = */ {Type::UNION, &MetadataFor<commands_aiding::FrameConfig::Rotation>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::FrameConfig::Rotation, &type::rotation>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::FrameConfig::Rotation, &type::rotation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -139,7 +139,7 @@ struct MetadataFor<commands_aiding::FrameConfig>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Reference frame number. Limit 4.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -148,7 +148,7 @@ struct MetadataFor<commands_aiding::FrameConfig>
             /* .name          = */ "format",
             /* .docs          = */ "Format of the transformation.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_aiding::FrameConfig::Format>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::FrameConfig::Format, &type::format>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::FrameConfig::Format, &type::format>,
             /* .attributes    = */ {true, true, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -157,7 +157,7 @@ struct MetadataFor<commands_aiding::FrameConfig>
             /* .name          = */ "tracking_enabled",
             /* .docs          = */ "If enabled, the Kalman filter will track errors.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::tracking_enabled>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::tracking_enabled>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -166,7 +166,7 @@ struct MetadataFor<commands_aiding::FrameConfig>
             /* .name          = */ "translation",
             /* .docs          = */ "Translation X, Y, and Z.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::translation>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::translation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -175,7 +175,7 @@ struct MetadataFor<commands_aiding::FrameConfig>
             /* .name          = */ "rotation",
             /* .docs          = */ "Rotation as specified by format.",
             /* .type          = */ {Type::UNION, &MetadataFor<commands_aiding::FrameConfig::Rotation>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::FrameConfig::Rotation, &type::rotation>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::FrameConfig::Rotation, &type::rotation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -224,7 +224,7 @@ struct MetadataFor<commands_aiding::EchoControl::Response>
             /* .name          = */ "mode",
             /* .docs          = */ "Controls data echoing.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_aiding::EchoControl::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::EchoControl::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::EchoControl::Mode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -254,7 +254,7 @@ struct MetadataFor<commands_aiding::EchoControl>
             /* .name          = */ "mode",
             /* .docs          = */ "Controls data echoing.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_aiding::EchoControl::Mode>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::EchoControl::Mode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::EchoControl::Mode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -303,7 +303,7 @@ struct MetadataFor<commands_aiding::Time>
             /* .name          = */ "timebase",
             /* .docs          = */ "Timebase reference, e.g. internal, external, GPS, UTC, etc.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_aiding::Time::Timebase>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time::Timebase, &type::timebase>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time::Timebase, &type::timebase>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -312,7 +312,7 @@ struct MetadataFor<commands_aiding::Time>
             /* .name          = */ "reserved",
             /* .docs          = */ "Reserved, set to 0x01.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -321,7 +321,7 @@ struct MetadataFor<commands_aiding::Time>
             /* .name          = */ "nanoseconds",
             /* .docs          = */ "Nanoseconds since the timebase epoch.",
             /* .type          = */ {Type::U64, nullptr},
-            /* .accessor      = */ utils::access<type, uint64_t, &type::nanoseconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint64_t, &type::nanoseconds>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -366,7 +366,7 @@ struct MetadataFor<commands_aiding::PosEcef>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -375,7 +375,7 @@ struct MetadataFor<commands_aiding::PosEcef>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -384,7 +384,7 @@ struct MetadataFor<commands_aiding::PosEcef>
             /* .name          = */ "position",
             /* .docs          = */ "ECEF position [m].",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::position>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::position>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -393,7 +393,7 @@ struct MetadataFor<commands_aiding::PosEcef>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "ECEF position uncertainty [m]. Cannot be 0 unless the corresponding valid flags are 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -402,7 +402,7 @@ struct MetadataFor<commands_aiding::PosEcef>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "Valid flags. Axes with 0 will be completely ignored.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_aiding::PosEcef::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::PosEcef::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::PosEcef::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -451,7 +451,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -460,7 +460,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -469,7 +469,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "latitude",
             /* .docs          = */ "[deg]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::latitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::latitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -478,7 +478,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "longitude",
             /* .docs          = */ "[deg]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::longitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::longitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -487,7 +487,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "height",
             /* .docs          = */ "[m]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::height>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -496,7 +496,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "NED position uncertainty. Cannot be 0 unless the corresponding valid flags are 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -505,7 +505,7 @@ struct MetadataFor<commands_aiding::PosLlh>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "Valid flags. Axes with 0 will be completely ignored.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_aiding::PosLlh::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::PosLlh::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::PosLlh::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -534,7 +534,7 @@ struct MetadataFor<commands_aiding::HeightAboveEllipsoid>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -543,7 +543,7 @@ struct MetadataFor<commands_aiding::HeightAboveEllipsoid>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -552,7 +552,7 @@ struct MetadataFor<commands_aiding::HeightAboveEllipsoid>
             /* .name          = */ "height",
             /* .docs          = */ "[m]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::height>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -561,7 +561,7 @@ struct MetadataFor<commands_aiding::HeightAboveEllipsoid>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "[m]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -570,7 +570,7 @@ struct MetadataFor<commands_aiding::HeightAboveEllipsoid>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -619,7 +619,7 @@ struct MetadataFor<commands_aiding::VelEcef>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -628,7 +628,7 @@ struct MetadataFor<commands_aiding::VelEcef>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -637,7 +637,7 @@ struct MetadataFor<commands_aiding::VelEcef>
             /* .name          = */ "velocity",
             /* .docs          = */ "ECEF velocity [m/s].",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -646,7 +646,7 @@ struct MetadataFor<commands_aiding::VelEcef>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "ECEF velocity uncertainty [m/s]. Cannot be 0 unless the corresponding valid flags are 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -655,7 +655,7 @@ struct MetadataFor<commands_aiding::VelEcef>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "Valid flags. Axes with 0 will be completely ignored.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_aiding::VelEcef::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::VelEcef::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::VelEcef::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -704,7 +704,7 @@ struct MetadataFor<commands_aiding::VelNed>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -713,7 +713,7 @@ struct MetadataFor<commands_aiding::VelNed>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -722,7 +722,7 @@ struct MetadataFor<commands_aiding::VelNed>
             /* .name          = */ "velocity",
             /* .docs          = */ "NED velocity [m/s].",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -731,7 +731,7 @@ struct MetadataFor<commands_aiding::VelNed>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "NED velocity uncertainty [m/s]. Cannot be 0 unless the corresponding valid flags are 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -740,7 +740,7 @@ struct MetadataFor<commands_aiding::VelNed>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "Valid flags. Axes with 0 will be completely ignored.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_aiding::VelNed::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::VelNed::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::VelNed::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -789,7 +789,7 @@ struct MetadataFor<commands_aiding::VelBodyFrame>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -798,7 +798,7 @@ struct MetadataFor<commands_aiding::VelBodyFrame>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -807,7 +807,7 @@ struct MetadataFor<commands_aiding::VelBodyFrame>
             /* .name          = */ "velocity",
             /* .docs          = */ "[m/s]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -816,7 +816,7 @@ struct MetadataFor<commands_aiding::VelBodyFrame>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "[m/s] 1-sigma uncertainty. Cannot be 0 unless the corresponding valid flags are 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -825,7 +825,7 @@ struct MetadataFor<commands_aiding::VelBodyFrame>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "Valid flags. Axes with 0 will be completely ignored.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_aiding::VelBodyFrame::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::VelBodyFrame::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::VelBodyFrame::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -854,7 +854,7 @@ struct MetadataFor<commands_aiding::HeadingTrue>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -863,7 +863,7 @@ struct MetadataFor<commands_aiding::HeadingTrue>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -872,7 +872,7 @@ struct MetadataFor<commands_aiding::HeadingTrue>
             /* .name          = */ "heading",
             /* .docs          = */ "Heading [radians]. Range +/- Pi.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -881,7 +881,7 @@ struct MetadataFor<commands_aiding::HeadingTrue>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "Cannot be 0 unless the valid flags are 0.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -890,7 +890,7 @@ struct MetadataFor<commands_aiding::HeadingTrue>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -939,7 +939,7 @@ struct MetadataFor<commands_aiding::MagneticField>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -948,7 +948,7 @@ struct MetadataFor<commands_aiding::MagneticField>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -957,7 +957,7 @@ struct MetadataFor<commands_aiding::MagneticField>
             /* .name          = */ "magnetic_field",
             /* .docs          = */ "[G]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::magnetic_field>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::magnetic_field>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -966,7 +966,7 @@ struct MetadataFor<commands_aiding::MagneticField>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "[G] 1-sigma uncertainty. Cannot be 0 unless the corresponding valid flags are 0.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -975,7 +975,7 @@ struct MetadataFor<commands_aiding::MagneticField>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "Valid flags. Axes with 0 will be completely ignored.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_aiding::MagneticField::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::MagneticField::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::MagneticField::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1004,7 +1004,7 @@ struct MetadataFor<commands_aiding::Pressure>
             /* .name          = */ "time",
             /* .docs          = */ "Timestamp of the measurement.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_aiding::Time>::value},
-            /* .accessor      = */ utils::access<type, commands_aiding::Time, &type::time>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_aiding::Time, &type::time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1013,7 +1013,7 @@ struct MetadataFor<commands_aiding::Pressure>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Source ID for this estimate (source_id == 0 indicates this sensor, source_id > 0 indicates an external estimate).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1022,7 +1022,7 @@ struct MetadataFor<commands_aiding::Pressure>
             /* .name          = */ "pressure",
             /* .docs          = */ "[mbar]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pressure>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pressure>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1031,7 +1031,7 @@ struct MetadataFor<commands_aiding::Pressure>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "[mbar] 1-sigma uncertainty. Cannot be 0 unless the valid flags are 0.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1040,7 +1040,7 @@ struct MetadataFor<commands_aiding::Pressure>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/commands_base.hpp b/src/cpp/mip/metadata/definitions/commands_base.hpp
index a88a99dd..a8b12c20 100644
--- a/src/cpp/mip/metadata/definitions/commands_base.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_base.hpp
@@ -54,7 +54,7 @@ struct MetadataFor<commands_base::BaseDeviceInfo>
             /* .name          = */ "firmware_version",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::firmware_version>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::firmware_version>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -63,7 +63,7 @@ struct MetadataFor<commands_base::BaseDeviceInfo>
             /* .name          = */ "model_name",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::model_name>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::model_name>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -72,7 +72,7 @@ struct MetadataFor<commands_base::BaseDeviceInfo>
             /* .name          = */ "model_number",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::model_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::model_number>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -81,7 +81,7 @@ struct MetadataFor<commands_base::BaseDeviceInfo>
             /* .name          = */ "serial_number",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::serial_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::serial_number>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -90,7 +90,7 @@ struct MetadataFor<commands_base::BaseDeviceInfo>
             /* .name          = */ "lot_number",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::lot_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::lot_number>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -99,7 +99,7 @@ struct MetadataFor<commands_base::BaseDeviceInfo>
             /* .name          = */ "device_options",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::device_options>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::device_options>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -124,7 +124,7 @@ struct MetadataFor<commands_base::GetDeviceInfo::Response>
             /* .name          = */ "device_info",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_base::BaseDeviceInfo>::value},
-            /* .accessor      = */ utils::access<type, commands_base::BaseDeviceInfo, &type::device_info>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_base::BaseDeviceInfo, &type::device_info>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -170,7 +170,7 @@ struct MetadataFor<commands_base::GetDeviceDescriptors::Response>
             /* .name          = */ "descriptors",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {0, microstrain::Index(1) /* descriptors_count */},
             /* .condition     = */ {},
@@ -179,7 +179,7 @@ struct MetadataFor<commands_base::GetDeviceDescriptors::Response>
             /* .name          = */ "descriptors_count",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::descriptors_count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::descriptors_count>,
             /* .attributes    = */ {false, false, false, false, false, /*echo*/false, /*virtual*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -225,7 +225,7 @@ struct MetadataFor<commands_base::BuiltInTest::Response>
             /* .name          = */ "result",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::result>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::result>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -288,7 +288,7 @@ struct MetadataFor<commands_base::GetExtendedDescriptors::Response>
             /* .name          = */ "descriptors",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::descriptors>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::descriptors>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {0, microstrain::Index(1) /* descriptors_count */},
             /* .condition     = */ {},
@@ -297,7 +297,7 @@ struct MetadataFor<commands_base::GetExtendedDescriptors::Response>
             /* .name          = */ "descriptors_count",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::descriptors_count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::descriptors_count>,
             /* .attributes    = */ {false, false, false, false, false, /*echo*/false, /*virtual*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -343,7 +343,7 @@ struct MetadataFor<commands_base::ContinuousBit::Response>
             /* .name          = */ "result",
             /* .docs          = */ "Device-specific bitfield (128 bits). See device user manual.\nBits are least-significant-byte first. For example, bit 0 is\nlocated at bit 0 of result[0], bit 1 is located at bit 1 of result[0],\nbit 8 is located at bit 0 of result[1], and bit 127 is located at bit\n7 of result[15].",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::result>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::result>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -389,7 +389,7 @@ struct MetadataFor<commands_base::CommSpeed::Response>
             /* .name          = */ "port",
             /* .docs          = */ "Port ID number, starting with 1. When function is SAVE, LOAD, or DEFAULT, this can be 0 to apply to all ports. See the device user manual for details.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::port>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::port>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -398,7 +398,7 @@ struct MetadataFor<commands_base::CommSpeed::Response>
             /* .name          = */ "baud",
             /* .docs          = */ "Port baud rate. Must be a supported rate.",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::baud>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::baud>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -428,7 +428,7 @@ struct MetadataFor<commands_base::CommSpeed>
             /* .name          = */ "port",
             /* .docs          = */ "Port ID number, starting with 1. When function is SAVE, LOAD, or DEFAULT, this can be 0 to apply to all ports. See the device user manual for details.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::port>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::port>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -437,7 +437,7 @@ struct MetadataFor<commands_base::CommSpeed>
             /* .name          = */ "baud",
             /* .docs          = */ "Port baud rate. Must be a supported rate.",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::baud>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::baud>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -486,7 +486,7 @@ struct MetadataFor<commands_base::GpsTimeUpdate>
             /* .name          = */ "field_id",
             /* .docs          = */ "Determines how to interpret value.",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_base::GpsTimeUpdate::FieldId>::value},
-            /* .accessor      = */ utils::access<type, commands_base::GpsTimeUpdate::FieldId, &type::field_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_base::GpsTimeUpdate::FieldId, &type::field_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -495,7 +495,7 @@ struct MetadataFor<commands_base::GpsTimeUpdate>
             /* .name          = */ "value",
             /* .docs          = */ "Week number or time of week, depending on the field_id.",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::value>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::value>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/commands_filter.hpp b/src/cpp/mip/metadata/definitions/commands_filter.hpp
index 3fa75990..006128be 100644
--- a/src/cpp/mip/metadata/definitions/commands_filter.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_filter.hpp
@@ -37,7 +37,7 @@ struct MetadataFor<commands_filter::SetInitialAttitude>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -46,7 +46,7 @@ struct MetadataFor<commands_filter::SetInitialAttitude>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -55,7 +55,7 @@ struct MetadataFor<commands_filter::SetInitialAttitude>
             /* .name          = */ "heading",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -108,7 +108,7 @@ struct MetadataFor<commands_filter::EstimationControl::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "See above",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_filter::EstimationControl::EnableFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::EstimationControl::EnableFlags, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::EstimationControl::EnableFlags, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -138,7 +138,7 @@ struct MetadataFor<commands_filter::EstimationControl>
             /* .name          = */ "enable",
             /* .docs          = */ "See above",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_filter::EstimationControl::EnableFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::EstimationControl::EnableFlags, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::EstimationControl::EnableFlags, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -167,7 +167,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "gps_time",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::gps_time>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::gps_time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -176,7 +176,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "gps_week",
             /* .docs          = */ "[GPS week number, not modulus 1024]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::gps_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::gps_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -185,7 +185,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "latitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::latitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::latitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -194,7 +194,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "longitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::longitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::longitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -203,7 +203,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "height",
             /* .docs          = */ "Above WGS84 ellipsoid [meters]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::height>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -212,7 +212,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "velocity",
             /* .docs          = */ "NED Frame [meters/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -221,7 +221,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "pos_uncertainty",
             /* .docs          = */ "NED Frame, 1-sigma [meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::pos_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::pos_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -230,7 +230,7 @@ struct MetadataFor<commands_filter::ExternalGnssUpdate>
             /* .name          = */ "vel_uncertainty",
             /* .docs          = */ "NED Frame, 1-sigma [meters/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::vel_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::vel_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -259,7 +259,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdate>
             /* .name          = */ "heading",
             /* .docs          = */ "Bounded by +-PI [radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -268,7 +268,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdate>
             /* .name          = */ "heading_uncertainty",
             /* .docs          = */ "1-sigma [radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -277,7 +277,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdate>
             /* .name          = */ "type",
             /* .docs          = */ "1 - True, 2 - Magnetic",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -306,7 +306,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdateWithTime>
             /* .name          = */ "gps_time",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::gps_time>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::gps_time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -315,7 +315,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdateWithTime>
             /* .name          = */ "gps_week",
             /* .docs          = */ "[GPS week number, not modulus 1024]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::gps_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::gps_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -324,7 +324,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdateWithTime>
             /* .name          = */ "heading",
             /* .docs          = */ "Relative to true north, bounded by +-PI [radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -333,7 +333,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdateWithTime>
             /* .name          = */ "heading_uncertainty",
             /* .docs          = */ "1-sigma [radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -342,7 +342,7 @@ struct MetadataFor<commands_filter::ExternalHeadingUpdateWithTime>
             /* .name          = */ "type",
             /* .docs          = */ "1 - True, 2 - Magnetic",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -391,7 +391,7 @@ struct MetadataFor<commands_filter::TareOrientation::Response>
             /* .name          = */ "axes",
             /* .docs          = */ "Axes to tare",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_filter::TareOrientation::MipTareAxes>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::TareOrientation::MipTareAxes, &type::axes>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::TareOrientation::MipTareAxes, &type::axes>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -421,7 +421,7 @@ struct MetadataFor<commands_filter::TareOrientation>
             /* .name          = */ "axes",
             /* .docs          = */ "Axes to tare",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_filter::TareOrientation::MipTareAxes>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::TareOrientation::MipTareAxes, &type::axes>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::TareOrientation::MipTareAxes, &type::axes>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -471,7 +471,7 @@ struct MetadataFor<commands_filter::VehicleDynamicsMode::Response>
             /* .name          = */ "mode",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::VehicleDynamicsMode::DynamicsMode>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::VehicleDynamicsMode::DynamicsMode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::VehicleDynamicsMode::DynamicsMode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -501,7 +501,7 @@ struct MetadataFor<commands_filter::VehicleDynamicsMode>
             /* .name          = */ "mode",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::VehicleDynamicsMode::DynamicsMode>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::VehicleDynamicsMode::DynamicsMode, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::VehicleDynamicsMode::DynamicsMode, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -530,7 +530,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationEuler::Response>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -539,7 +539,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationEuler::Response>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -548,7 +548,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationEuler::Response>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -578,7 +578,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationEuler>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -587,7 +587,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationEuler>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -596,7 +596,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationEuler>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -625,7 +625,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationDcm::Response>
             /* .name          = */ "dcm",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::dcm>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::dcm>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -655,7 +655,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationDcm>
             /* .name          = */ "dcm",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::dcm>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::dcm>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -684,7 +684,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationQuaternion::Response>
             /* .name          = */ "quat",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::quat>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::quat>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -714,7 +714,7 @@ struct MetadataFor<commands_filter::SensorToVehicleRotationQuaternion>
             /* .name          = */ "quat",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::quat>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::quat>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -743,7 +743,7 @@ struct MetadataFor<commands_filter::SensorToVehicleOffset::Response>
             /* .name          = */ "offset",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -773,7 +773,7 @@ struct MetadataFor<commands_filter::SensorToVehicleOffset>
             /* .name          = */ "offset",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -802,7 +802,7 @@ struct MetadataFor<commands_filter::AntennaOffset::Response>
             /* .name          = */ "offset",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -832,7 +832,7 @@ struct MetadataFor<commands_filter::AntennaOffset>
             /* .name          = */ "offset",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -882,7 +882,7 @@ struct MetadataFor<commands_filter::GnssSource::Response>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::GnssSource::Source>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::GnssSource::Source, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::GnssSource::Source, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -912,7 +912,7 @@ struct MetadataFor<commands_filter::GnssSource>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::GnssSource::Source>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::GnssSource::Source, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::GnssSource::Source, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -966,7 +966,7 @@ struct MetadataFor<commands_filter::HeadingSource::Response>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::HeadingSource::Source>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::HeadingSource::Source, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::HeadingSource::Source, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -996,7 +996,7 @@ struct MetadataFor<commands_filter::HeadingSource>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::HeadingSource::Source>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::HeadingSource::Source, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::HeadingSource::Source, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1025,7 +1025,7 @@ struct MetadataFor<commands_filter::AutoInitControl::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "See above",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1055,7 +1055,7 @@ struct MetadataFor<commands_filter::AutoInitControl>
             /* .name          = */ "enable",
             /* .docs          = */ "See above",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1084,7 +1084,7 @@ struct MetadataFor<commands_filter::AccelNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Accel Noise 1-sigma [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1114,7 +1114,7 @@ struct MetadataFor<commands_filter::AccelNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Accel Noise 1-sigma [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1143,7 +1143,7 @@ struct MetadataFor<commands_filter::GyroNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Gyro Noise 1-sigma [rad/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1173,7 +1173,7 @@ struct MetadataFor<commands_filter::GyroNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Gyro Noise 1-sigma [rad/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1202,7 +1202,7 @@ struct MetadataFor<commands_filter::AccelBiasModel::Response>
             /* .name          = */ "beta",
             /* .docs          = */ "Accel Bias Beta [1/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::beta>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::beta>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1211,7 +1211,7 @@ struct MetadataFor<commands_filter::AccelBiasModel::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Accel Noise 1-sigma [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1241,7 +1241,7 @@ struct MetadataFor<commands_filter::AccelBiasModel>
             /* .name          = */ "beta",
             /* .docs          = */ "Accel Bias Beta [1/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::beta>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::beta>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1250,7 +1250,7 @@ struct MetadataFor<commands_filter::AccelBiasModel>
             /* .name          = */ "noise",
             /* .docs          = */ "Accel Noise 1-sigma [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1279,7 +1279,7 @@ struct MetadataFor<commands_filter::GyroBiasModel::Response>
             /* .name          = */ "beta",
             /* .docs          = */ "Gyro Bias Beta [1/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::beta>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::beta>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1288,7 +1288,7 @@ struct MetadataFor<commands_filter::GyroBiasModel::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Gyro Noise 1-sigma [rad/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1318,7 +1318,7 @@ struct MetadataFor<commands_filter::GyroBiasModel>
             /* .name          = */ "beta",
             /* .docs          = */ "Gyro Bias Beta [1/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::beta>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::beta>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1327,7 +1327,7 @@ struct MetadataFor<commands_filter::GyroBiasModel>
             /* .name          = */ "noise",
             /* .docs          = */ "Gyro Noise 1-sigma [rad/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1375,7 +1375,7 @@ struct MetadataFor<commands_filter::AltitudeAiding::Response>
             /* .name          = */ "selector",
             /* .docs          = */ "See above",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::AltitudeAiding::AidingSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::AltitudeAiding::AidingSelector, &type::selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::AltitudeAiding::AidingSelector, &type::selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1405,7 +1405,7 @@ struct MetadataFor<commands_filter::AltitudeAiding>
             /* .name          = */ "selector",
             /* .docs          = */ "See above",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::AltitudeAiding::AidingSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::AltitudeAiding::AidingSelector, &type::selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::AltitudeAiding::AidingSelector, &type::selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1453,7 +1453,7 @@ struct MetadataFor<commands_filter::PitchRollAiding::Response>
             /* .name          = */ "source",
             /* .docs          = */ "Controls the aiding source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::PitchRollAiding::AidingSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::PitchRollAiding::AidingSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::PitchRollAiding::AidingSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1483,7 +1483,7 @@ struct MetadataFor<commands_filter::PitchRollAiding>
             /* .name          = */ "source",
             /* .docs          = */ "Controls the aiding source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::PitchRollAiding::AidingSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::PitchRollAiding::AidingSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::PitchRollAiding::AidingSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1512,7 +1512,7 @@ struct MetadataFor<commands_filter::AutoZupt::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1521,7 +1521,7 @@ struct MetadataFor<commands_filter::AutoZupt::Response>
             /* .name          = */ "threshold",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::threshold>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::threshold>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1551,7 +1551,7 @@ struct MetadataFor<commands_filter::AutoZupt>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1560,7 +1560,7 @@ struct MetadataFor<commands_filter::AutoZupt>
             /* .name          = */ "threshold",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::threshold>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::threshold>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1589,7 +1589,7 @@ struct MetadataFor<commands_filter::AutoAngularZupt::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1598,7 +1598,7 @@ struct MetadataFor<commands_filter::AutoAngularZupt::Response>
             /* .name          = */ "threshold",
             /* .docs          = */ "[radians/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::threshold>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::threshold>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1628,7 +1628,7 @@ struct MetadataFor<commands_filter::AutoAngularZupt>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1637,7 +1637,7 @@ struct MetadataFor<commands_filter::AutoAngularZupt>
             /* .name          = */ "threshold",
             /* .docs          = */ "[radians/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::threshold>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::threshold>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1722,7 +1722,7 @@ struct MetadataFor<commands_filter::GravityNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Gravity Noise 1-sigma [gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1752,7 +1752,7 @@ struct MetadataFor<commands_filter::GravityNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Gravity Noise 1-sigma [gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1781,7 +1781,7 @@ struct MetadataFor<commands_filter::PressureAltitudeNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Pressure Altitude Noise 1-sigma [m]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1811,7 +1811,7 @@ struct MetadataFor<commands_filter::PressureAltitudeNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Pressure Altitude Noise 1-sigma [m]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1840,7 +1840,7 @@ struct MetadataFor<commands_filter::HardIronOffsetNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Hard Iron Offset Noise 1-sigma [gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1870,7 +1870,7 @@ struct MetadataFor<commands_filter::HardIronOffsetNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Hard Iron Offset Noise 1-sigma [gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1899,7 +1899,7 @@ struct MetadataFor<commands_filter::SoftIronMatrixNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Soft Iron Matrix Noise 1-sigma [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1929,7 +1929,7 @@ struct MetadataFor<commands_filter::SoftIronMatrixNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Soft Iron Matrix Noise 1-sigma [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1958,7 +1958,7 @@ struct MetadataFor<commands_filter::MagNoise::Response>
             /* .name          = */ "noise",
             /* .docs          = */ "Mag Noise 1-sigma [gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1988,7 +1988,7 @@ struct MetadataFor<commands_filter::MagNoise>
             /* .name          = */ "noise",
             /* .docs          = */ "Mag Noise 1-sigma [gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::noise>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::noise>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2037,7 +2037,7 @@ struct MetadataFor<commands_filter::InclinationSource::Response>
             /* .name          = */ "source",
             /* .docs          = */ "Inclination Source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterMagParamSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2046,7 +2046,7 @@ struct MetadataFor<commands_filter::InclinationSource::Response>
             /* .name          = */ "inclination",
             /* .docs          = */ "Inclination angle [radians] (only required if source = MANUAL)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::inclination>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::inclination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2076,7 +2076,7 @@ struct MetadataFor<commands_filter::InclinationSource>
             /* .name          = */ "source",
             /* .docs          = */ "Inclination Source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterMagParamSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2085,7 +2085,7 @@ struct MetadataFor<commands_filter::InclinationSource>
             /* .name          = */ "inclination",
             /* .docs          = */ "Inclination angle [radians] (only required if source = MANUAL)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::inclination>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::inclination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2114,7 +2114,7 @@ struct MetadataFor<commands_filter::MagneticDeclinationSource::Response>
             /* .name          = */ "source",
             /* .docs          = */ "Magnetic field declination angle source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterMagParamSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2123,7 +2123,7 @@ struct MetadataFor<commands_filter::MagneticDeclinationSource::Response>
             /* .name          = */ "declination",
             /* .docs          = */ "Declination angle [radians] (only required if source = MANUAL)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::declination>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::declination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2153,7 +2153,7 @@ struct MetadataFor<commands_filter::MagneticDeclinationSource>
             /* .name          = */ "source",
             /* .docs          = */ "Magnetic field declination angle source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterMagParamSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2162,7 +2162,7 @@ struct MetadataFor<commands_filter::MagneticDeclinationSource>
             /* .name          = */ "declination",
             /* .docs          = */ "Declination angle [radians] (only required if source = MANUAL)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::declination>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::declination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2191,7 +2191,7 @@ struct MetadataFor<commands_filter::MagFieldMagnitudeSource::Response>
             /* .name          = */ "source",
             /* .docs          = */ "Magnetic Field Magnitude Source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterMagParamSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2200,7 +2200,7 @@ struct MetadataFor<commands_filter::MagFieldMagnitudeSource::Response>
             /* .name          = */ "magnitude",
             /* .docs          = */ "Magnitude [gauss] (only required if source = MANUAL)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::magnitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::magnitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2230,7 +2230,7 @@ struct MetadataFor<commands_filter::MagFieldMagnitudeSource>
             /* .name          = */ "source",
             /* .docs          = */ "Magnetic Field Magnitude Source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterMagParamSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterMagParamSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2239,7 +2239,7 @@ struct MetadataFor<commands_filter::MagFieldMagnitudeSource>
             /* .name          = */ "magnitude",
             /* .docs          = */ "Magnitude [gauss] (only required if source = MANUAL)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::magnitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::magnitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2268,7 +2268,7 @@ struct MetadataFor<commands_filter::ReferencePosition::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "enable/disable",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2277,7 +2277,7 @@ struct MetadataFor<commands_filter::ReferencePosition::Response>
             /* .name          = */ "latitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::latitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::latitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2286,7 +2286,7 @@ struct MetadataFor<commands_filter::ReferencePosition::Response>
             /* .name          = */ "longitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::longitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::longitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2295,7 +2295,7 @@ struct MetadataFor<commands_filter::ReferencePosition::Response>
             /* .name          = */ "altitude",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::altitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::altitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2325,7 +2325,7 @@ struct MetadataFor<commands_filter::ReferencePosition>
             /* .name          = */ "enable",
             /* .docs          = */ "enable/disable",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2334,7 +2334,7 @@ struct MetadataFor<commands_filter::ReferencePosition>
             /* .name          = */ "latitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::latitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::latitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2343,7 +2343,7 @@ struct MetadataFor<commands_filter::ReferencePosition>
             /* .name          = */ "longitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::longitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::longitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2352,7 +2352,7 @@ struct MetadataFor<commands_filter::ReferencePosition>
             /* .name          = */ "altitude",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::altitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::altitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2401,7 +2401,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "adaptive_measurement",
             /* .docs          = */ "Adaptive measurement selector",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterAdaptiveMeasurement>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2410,7 +2410,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "frequency",
             /* .docs          = */ "Low-pass filter curoff frequency [hertz]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2419,7 +2419,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "low_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2428,7 +2428,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "high_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2437,7 +2437,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "low_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2446,7 +2446,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "high_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2455,7 +2455,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement::Resp
             /* .name          = */ "minimum_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::minimum_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::minimum_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2485,7 +2485,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "adaptive_measurement",
             /* .docs          = */ "Adaptive measurement selector",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterAdaptiveMeasurement>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2494,7 +2494,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "frequency",
             /* .docs          = */ "Low-pass filter curoff frequency [hertz]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2503,7 +2503,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "low_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2512,7 +2512,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "high_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2521,7 +2521,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "low_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2530,7 +2530,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "high_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2539,7 +2539,7 @@ struct MetadataFor<commands_filter::AccelMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "minimum_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::minimum_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::minimum_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2568,7 +2568,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "adaptive_measurement",
             /* .docs          = */ "Adaptive measurement selector",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterAdaptiveMeasurement>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2577,7 +2577,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "frequency",
             /* .docs          = */ "Low-pass filter curoff frequency [hertz]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2586,7 +2586,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "low_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2595,7 +2595,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "high_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2604,7 +2604,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "low_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2613,7 +2613,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "high_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2622,7 +2622,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement::Respon
             /* .name          = */ "minimum_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::minimum_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::minimum_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2652,7 +2652,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "adaptive_measurement",
             /* .docs          = */ "Adaptive measurement selector",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterAdaptiveMeasurement>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterAdaptiveMeasurement, &type::adaptive_measurement>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2661,7 +2661,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "frequency",
             /* .docs          = */ "Low-pass filter curoff frequency [hertz]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2670,7 +2670,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "low_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2679,7 +2679,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "high_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2688,7 +2688,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "low_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::low_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::low_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2697,7 +2697,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "high_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2706,7 +2706,7 @@ struct MetadataFor<commands_filter::MagMagnitudeErrorAdaptiveMeasurement>
             /* .name          = */ "minimum_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::minimum_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::minimum_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2735,7 +2735,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement::Respons
             /* .name          = */ "enable",
             /* .docs          = */ "Enable/Disable",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2744,7 +2744,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement::Respons
             /* .name          = */ "frequency",
             /* .docs          = */ "Low-pass filter curoff frequency [hertz]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2753,7 +2753,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement::Respons
             /* .name          = */ "high_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2762,7 +2762,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement::Respons
             /* .name          = */ "high_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2771,7 +2771,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement::Respons
             /* .name          = */ "minimum_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::minimum_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::minimum_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2801,7 +2801,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement>
             /* .name          = */ "enable",
             /* .docs          = */ "Enable/Disable",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2810,7 +2810,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement>
             /* .name          = */ "frequency",
             /* .docs          = */ "Low-pass filter curoff frequency [hertz]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::frequency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::frequency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2819,7 +2819,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement>
             /* .name          = */ "high_limit",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2828,7 +2828,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement>
             /* .name          = */ "high_limit_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::high_limit_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::high_limit_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2837,7 +2837,7 @@ struct MetadataFor<commands_filter::MagDipAngleErrorAdaptiveMeasurement>
             /* .name          = */ "minimum_uncertainty",
             /* .docs          = */ "1-Sigma [meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::minimum_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::minimum_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2893,7 +2893,7 @@ struct MetadataFor<commands_filter::AidingMeasurementEnable::Response>
             /* .name          = */ "aiding_source",
             /* .docs          = */ "Aiding measurement source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::AidingMeasurementEnable::AidingSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::AidingMeasurementEnable::AidingSource, &type::aiding_source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::AidingMeasurementEnable::AidingSource, &type::aiding_source>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2902,7 +2902,7 @@ struct MetadataFor<commands_filter::AidingMeasurementEnable::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "Controls the aiding source",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2932,7 +2932,7 @@ struct MetadataFor<commands_filter::AidingMeasurementEnable>
             /* .name          = */ "aiding_source",
             /* .docs          = */ "Aiding measurement source",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::AidingMeasurementEnable::AidingSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::AidingMeasurementEnable::AidingSource, &type::aiding_source>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::AidingMeasurementEnable::AidingSource, &type::aiding_source>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2941,7 +2941,7 @@ struct MetadataFor<commands_filter::AidingMeasurementEnable>
             /* .name          = */ "enable",
             /* .docs          = */ "Controls the aiding source",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2987,7 +2987,7 @@ struct MetadataFor<commands_filter::KinematicConstraint::Response>
             /* .name          = */ "acceleration_constraint_selection",
             /* .docs          = */ "Acceleration constraint: <br/>\n0=None (default), <br/>\n1=Zero-acceleration.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::acceleration_constraint_selection>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::acceleration_constraint_selection>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2996,7 +2996,7 @@ struct MetadataFor<commands_filter::KinematicConstraint::Response>
             /* .name          = */ "velocity_constraint_selection",
             /* .docs          = */ "0=None (default), <br/>\n1=Zero-velocity, <br/>\n2=Wheeled-vehicle. <br/>",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::velocity_constraint_selection>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::velocity_constraint_selection>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3005,7 +3005,7 @@ struct MetadataFor<commands_filter::KinematicConstraint::Response>
             /* .name          = */ "angular_constraint_selection",
             /* .docs          = */ "0=None (default),\n1=Zero-angular rate (ZUPT).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::angular_constraint_selection>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::angular_constraint_selection>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3035,7 +3035,7 @@ struct MetadataFor<commands_filter::KinematicConstraint>
             /* .name          = */ "acceleration_constraint_selection",
             /* .docs          = */ "Acceleration constraint: <br/>\n0=None (default), <br/>\n1=Zero-acceleration.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::acceleration_constraint_selection>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::acceleration_constraint_selection>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3044,7 +3044,7 @@ struct MetadataFor<commands_filter::KinematicConstraint>
             /* .name          = */ "velocity_constraint_selection",
             /* .docs          = */ "0=None (default), <br/>\n1=Zero-velocity, <br/>\n2=Wheeled-vehicle. <br/>",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::velocity_constraint_selection>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::velocity_constraint_selection>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3053,7 +3053,7 @@ struct MetadataFor<commands_filter::KinematicConstraint>
             /* .name          = */ "angular_constraint_selection",
             /* .docs          = */ "0=None (default),\n1=Zero-angular rate (ZUPT).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::angular_constraint_selection>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::angular_constraint_selection>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3143,7 +3143,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "wait_for_run_command",
             /* .docs          = */ "Initialize filter only after receiving 'run' command",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::wait_for_run_command>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::wait_for_run_command>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3152,7 +3152,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "initial_cond_src",
             /* .docs          = */ "Initial condition source:",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::InitializationConfiguration::InitialConditionSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::InitializationConfiguration::InitialConditionSource, &type::initial_cond_src>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::InitializationConfiguration::InitialConditionSource, &type::initial_cond_src>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3161,7 +3161,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "auto_heading_alignment_selector",
             /* .docs          = */ "Bitfield specifying the allowed automatic heading alignment methods for automatic initial conditions. Bits are set to 1 to enable, and the correspond to the following: <br/>",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_filter::InitializationConfiguration::AlignmentSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::InitializationConfiguration::AlignmentSelector, &type::auto_heading_alignment_selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::InitializationConfiguration::AlignmentSelector, &type::auto_heading_alignment_selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3170,7 +3170,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "initial_heading",
             /* .docs          = */ "User-specified initial platform heading (degrees).",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::initial_heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::initial_heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3179,7 +3179,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "initial_pitch",
             /* .docs          = */ "User-specified initial platform pitch (degrees)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::initial_pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::initial_pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3188,7 +3188,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "initial_roll",
             /* .docs          = */ "User-specified initial platform roll (degrees)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::initial_roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::initial_roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3197,7 +3197,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "initial_position",
             /* .docs          = */ "User-specified initial platform position (units determined by reference frame selector, see note.)",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::initial_position>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::initial_position>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3206,7 +3206,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "initial_velocity",
             /* .docs          = */ "User-specified initial platform velocity (units determined by reference frame selector, see note.)",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::initial_velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::initial_velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3215,7 +3215,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration::Response>
             /* .name          = */ "reference_frame_selector",
             /* .docs          = */ "User-specified initial position/velocity reference frames",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterReferenceFrame>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3245,7 +3245,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "wait_for_run_command",
             /* .docs          = */ "Initialize filter only after receiving 'run' command",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::wait_for_run_command>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::wait_for_run_command>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3254,7 +3254,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "initial_cond_src",
             /* .docs          = */ "Initial condition source:",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::InitializationConfiguration::InitialConditionSource>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::InitializationConfiguration::InitialConditionSource, &type::initial_cond_src>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::InitializationConfiguration::InitialConditionSource, &type::initial_cond_src>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3263,7 +3263,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "auto_heading_alignment_selector",
             /* .docs          = */ "Bitfield specifying the allowed automatic heading alignment methods for automatic initial conditions. Bits are set to 1 to enable, and the correspond to the following: <br/>",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_filter::InitializationConfiguration::AlignmentSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::InitializationConfiguration::AlignmentSelector, &type::auto_heading_alignment_selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::InitializationConfiguration::AlignmentSelector, &type::auto_heading_alignment_selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3272,7 +3272,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "initial_heading",
             /* .docs          = */ "User-specified initial platform heading (degrees).",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::initial_heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::initial_heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3281,7 +3281,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "initial_pitch",
             /* .docs          = */ "User-specified initial platform pitch (degrees)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::initial_pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::initial_pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3290,7 +3290,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "initial_roll",
             /* .docs          = */ "User-specified initial platform roll (degrees)",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::initial_roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::initial_roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3299,7 +3299,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "initial_position",
             /* .docs          = */ "User-specified initial platform position (units determined by reference frame selector, see note.)",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::initial_position>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::initial_position>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3308,7 +3308,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "initial_velocity",
             /* .docs          = */ "User-specified initial platform velocity (units determined by reference frame selector, see note.)",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::initial_velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::initial_velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3317,7 +3317,7 @@ struct MetadataFor<commands_filter::InitializationConfiguration>
             /* .name          = */ "reference_frame_selector",
             /* .docs          = */ "User-specified initial position/velocity reference frames",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterReferenceFrame>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3346,7 +3346,7 @@ struct MetadataFor<commands_filter::AdaptiveFilterOptions::Response>
             /* .name          = */ "level",
             /* .docs          = */ "Auto-adaptive operating level: <br/>\n0=Off, <br/>\n1=Conservative, <br/>\n2=Moderate (default), <br/>\n3=Aggressive.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::level>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::level>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3355,7 +3355,7 @@ struct MetadataFor<commands_filter::AdaptiveFilterOptions::Response>
             /* .name          = */ "time_limit",
             /* .docs          = */ "Maximum duration of measurement rejection before entering recovery mode    (ms)",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::time_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::time_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3385,7 +3385,7 @@ struct MetadataFor<commands_filter::AdaptiveFilterOptions>
             /* .name          = */ "level",
             /* .docs          = */ "Auto-adaptive operating level: <br/>\n0=Off, <br/>\n1=Conservative, <br/>\n2=Moderate (default), <br/>\n3=Aggressive.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::level>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::level>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3394,7 +3394,7 @@ struct MetadataFor<commands_filter::AdaptiveFilterOptions>
             /* .name          = */ "time_limit",
             /* .docs          = */ "Maximum duration of measurement rejection before entering recovery mode    (ms)",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::time_limit>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::time_limit>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3423,7 +3423,7 @@ struct MetadataFor<commands_filter::MultiAntennaOffset::Response>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3432,7 +3432,7 @@ struct MetadataFor<commands_filter::MultiAntennaOffset::Response>
             /* .name          = */ "antenna_offset",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::antenna_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::antenna_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3462,7 +3462,7 @@ struct MetadataFor<commands_filter::MultiAntennaOffset>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "Receiver: 1, 2, etc...",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3471,7 +3471,7 @@ struct MetadataFor<commands_filter::MultiAntennaOffset>
             /* .name          = */ "antenna_offset",
             /* .docs          = */ "Antenna lever arm offset vector in the vehicle frame (m)",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::antenna_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::antenna_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3500,7 +3500,7 @@ struct MetadataFor<commands_filter::RelPosConfiguration::Response>
             /* .name          = */ "source",
             /* .docs          = */ "0 - auto (RTK base station), 1 - manual",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3509,7 +3509,7 @@ struct MetadataFor<commands_filter::RelPosConfiguration::Response>
             /* .name          = */ "reference_frame_selector",
             /* .docs          = */ "ECEF or LLH",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterReferenceFrame>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3518,7 +3518,7 @@ struct MetadataFor<commands_filter::RelPosConfiguration::Response>
             /* .name          = */ "reference_coordinates",
             /* .docs          = */ "reference coordinates, units determined by source selection",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::reference_coordinates>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::reference_coordinates>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3548,7 +3548,7 @@ struct MetadataFor<commands_filter::RelPosConfiguration>
             /* .name          = */ "source",
             /* .docs          = */ "0 - auto (RTK base station), 1 - manual",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3557,7 +3557,7 @@ struct MetadataFor<commands_filter::RelPosConfiguration>
             /* .name          = */ "reference_frame_selector",
             /* .docs          = */ "ECEF or LLH",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::FilterReferenceFrame>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::FilterReferenceFrame, &type::reference_frame_selector>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3566,7 +3566,7 @@ struct MetadataFor<commands_filter::RelPosConfiguration>
             /* .name          = */ "reference_coordinates",
             /* .docs          = */ "reference coordinates, units determined by source selection",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::reference_coordinates>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::reference_coordinates>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3613,7 +3613,7 @@ struct MetadataFor<commands_filter::RefPointLeverArm::Response>
             /* .name          = */ "ref_point_sel",
             /* .docs          = */ "Reserved, must be 1",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::RefPointLeverArm::ReferencePointSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::RefPointLeverArm::ReferencePointSelector, &type::ref_point_sel>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::RefPointLeverArm::ReferencePointSelector, &type::ref_point_sel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3622,7 +3622,7 @@ struct MetadataFor<commands_filter::RefPointLeverArm::Response>
             /* .name          = */ "lever_arm_offset",
             /* .docs          = */ "[m] Lever arm offset vector in the vehicle's reference frame.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::lever_arm_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::lever_arm_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3652,7 +3652,7 @@ struct MetadataFor<commands_filter::RefPointLeverArm>
             /* .name          = */ "ref_point_sel",
             /* .docs          = */ "Reserved, must be 1",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_filter::RefPointLeverArm::ReferencePointSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_filter::RefPointLeverArm::ReferencePointSelector, &type::ref_point_sel>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_filter::RefPointLeverArm::ReferencePointSelector, &type::ref_point_sel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3661,7 +3661,7 @@ struct MetadataFor<commands_filter::RefPointLeverArm>
             /* .name          = */ "lever_arm_offset",
             /* .docs          = */ "[m] Lever arm offset vector in the vehicle's reference frame.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::lever_arm_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::lever_arm_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3690,7 +3690,7 @@ struct MetadataFor<commands_filter::SpeedMeasurement>
             /* .name          = */ "source",
             /* .docs          = */ "Reserved, must be 1.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3699,7 +3699,7 @@ struct MetadataFor<commands_filter::SpeedMeasurement>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS time of week when speed was sampled",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3708,7 +3708,7 @@ struct MetadataFor<commands_filter::SpeedMeasurement>
             /* .name          = */ "speed",
             /* .docs          = */ "Estimated speed along vehicle's x-axis (may be positive or negative) [meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::speed>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::speed>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3717,7 +3717,7 @@ struct MetadataFor<commands_filter::SpeedMeasurement>
             /* .name          = */ "speed_uncertainty",
             /* .docs          = */ "Estimated uncertainty in the speed measurement (1-sigma value) [meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::speed_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::speed_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3746,7 +3746,7 @@ struct MetadataFor<commands_filter::SpeedLeverArm::Response>
             /* .name          = */ "source",
             /* .docs          = */ "Reserved, must be 1.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3755,7 +3755,7 @@ struct MetadataFor<commands_filter::SpeedLeverArm::Response>
             /* .name          = */ "lever_arm_offset",
             /* .docs          = */ "[m] Lever arm offset vector in the vehicle's reference frame.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::lever_arm_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::lever_arm_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3785,7 +3785,7 @@ struct MetadataFor<commands_filter::SpeedLeverArm>
             /* .name          = */ "source",
             /* .docs          = */ "Reserved, must be 1.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source>,
             /* .attributes    = */ {true, true, true, true, true, /*echo*/true},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3794,7 +3794,7 @@ struct MetadataFor<commands_filter::SpeedLeverArm>
             /* .name          = */ "lever_arm_offset",
             /* .docs          = */ "[m] Lever arm offset vector in the vehicle's reference frame.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::lever_arm_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::lever_arm_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3823,7 +3823,7 @@ struct MetadataFor<commands_filter::WheeledVehicleConstraintControl::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3853,7 +3853,7 @@ struct MetadataFor<commands_filter::WheeledVehicleConstraintControl>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3882,7 +3882,7 @@ struct MetadataFor<commands_filter::VerticalGyroConstraintControl::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3912,7 +3912,7 @@ struct MetadataFor<commands_filter::VerticalGyroConstraintControl>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3941,7 +3941,7 @@ struct MetadataFor<commands_filter::GnssAntennaCalControl::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3950,7 +3950,7 @@ struct MetadataFor<commands_filter::GnssAntennaCalControl::Response>
             /* .name          = */ "max_offset",
             /* .docs          = */ "Maximum absolute value of lever arm offset error in the vehicle frame [meters]. See device user manual for the valid range of this parameter.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::max_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::max_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3980,7 +3980,7 @@ struct MetadataFor<commands_filter::GnssAntennaCalControl>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disable, 1 - Enable",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3989,7 +3989,7 @@ struct MetadataFor<commands_filter::GnssAntennaCalControl>
             /* .name          = */ "max_offset",
             /* .docs          = */ "Maximum absolute value of lever arm offset error in the vehicle frame [meters]. See device user manual for the valid range of this parameter.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::max_offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::max_offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -4018,7 +4018,7 @@ struct MetadataFor<commands_filter::SetInitialHeading>
             /* .name          = */ "heading",
             /* .docs          = */ "Initial heading in radians [-pi, pi]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/commands_gnss.hpp b/src/cpp/mip/metadata/definitions/commands_gnss.hpp
index ecb421bb..33b422c9 100644
--- a/src/cpp/mip/metadata/definitions/commands_gnss.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_gnss.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<commands_gnss::ReceiverInfo::Info>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "Receiver id: e.g. 1, 2, etc.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -29,7 +29,7 @@ struct MetadataFor<commands_gnss::ReceiverInfo::Info>
             /* .name          = */ "mip_data_descriptor_set",
             /* .docs          = */ "MIP descriptor set associated with this receiver",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::mip_data_descriptor_set>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::mip_data_descriptor_set>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -38,7 +38,7 @@ struct MetadataFor<commands_gnss::ReceiverInfo::Info>
             /* .name          = */ "description",
             /* .docs          = */ "Ascii description of receiver. Contains the following info (comma-delimited):<br/>\nModule name/model<br/>\nFirmware version info",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::description>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::description>,
             /* .attributes    = */ NO_FUNCTIONS,
             /* .count         = */ 32,
             /* .condition     = */ {},
@@ -63,7 +63,7 @@ struct MetadataFor<commands_gnss::ReceiverInfo::Response>
             /* .name          = */ "num_receivers",
             /* .docs          = */ "Number of physical receivers in the device",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_receivers>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_receivers>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -72,7 +72,7 @@ struct MetadataFor<commands_gnss::ReceiverInfo::Response>
             /* .name          = */ "receiver_info",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<commands_gnss::ReceiverInfo::Info>::value},
-            /* .accessor      = */ utils::access<type, commands_gnss::ReceiverInfo::Info, &type::receiver_info>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_gnss::ReceiverInfo::Info, &type::receiver_info>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ {5, microstrain::Index(0) /* num_receivers */},
             /* .condition     = */ {},
@@ -118,7 +118,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration::Response>
             /* .name          = */ "gps_enable",
             /* .docs          = */ "Bitfield 0: Enable L1CA, 1: Enable L2C, 2: Enable L5",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::gps_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::gps_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -127,7 +127,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration::Response>
             /* .name          = */ "glonass_enable",
             /* .docs          = */ "Bitfield 0: Enable L1OF, 1: Enable L2OF",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::glonass_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::glonass_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -136,7 +136,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration::Response>
             /* .name          = */ "galileo_enable",
             /* .docs          = */ "Bitfield 0: Enable E1,   1: Enable E5B, 2: Enable E5A",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::galileo_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::galileo_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -145,7 +145,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration::Response>
             /* .name          = */ "beidou_enable",
             /* .docs          = */ "Bitfield 0: Enable B1,   1: Enable B2,  2: Enable B2A",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::beidou_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::beidou_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -154,7 +154,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration::Response>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -184,7 +184,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration>
             /* .name          = */ "gps_enable",
             /* .docs          = */ "Bitfield 0: Enable L1CA, 1: Enable L2C, 2: Enable L5",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::gps_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::gps_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -193,7 +193,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration>
             /* .name          = */ "glonass_enable",
             /* .docs          = */ "Bitfield 0: Enable L1OF, 1: Enable L2OF",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::glonass_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::glonass_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -202,7 +202,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration>
             /* .name          = */ "galileo_enable",
             /* .docs          = */ "Bitfield 0: Enable E1,   1: Enable E5B, 2: Enable E5A",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::galileo_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::galileo_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -211,7 +211,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration>
             /* .name          = */ "beidou_enable",
             /* .docs          = */ "Bitfield 0: Enable B1,   1: Enable B2,  2: Enable B2A",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::beidou_enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::beidou_enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -220,7 +220,7 @@ struct MetadataFor<commands_gnss::SignalConfiguration>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -249,7 +249,7 @@ struct MetadataFor<commands_gnss::RtkDongleConfiguration::Response>
             /* .name          = */ "enable",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -258,7 +258,7 @@ struct MetadataFor<commands_gnss::RtkDongleConfiguration::Response>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 3,
             /* .condition     = */ {},
@@ -288,7 +288,7 @@ struct MetadataFor<commands_gnss::RtkDongleConfiguration>
             /* .name          = */ "enable",
             /* .docs          = */ "0 - Disabled, 1- Enabled",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::enable>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::enable>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -297,7 +297,7 @@ struct MetadataFor<commands_gnss::RtkDongleConfiguration>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 3,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/commands_rtk.hpp b/src/cpp/mip/metadata/definitions/commands_rtk.hpp
index 45f67104..ebc4e079 100644
--- a/src/cpp/mip/metadata/definitions/commands_rtk.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_rtk.hpp
@@ -77,7 +77,7 @@ struct MetadataFor<commands_rtk::GetStatusFlags::Response>
             /* .name          = */ "flags",
             /* .docs          = */ "Model number dependent. See above structures.",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_rtk::GetStatusFlags::StatusFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_rtk::GetStatusFlags::StatusFlags, &type::flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_rtk::GetStatusFlags::StatusFlags, &type::flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -123,7 +123,7 @@ struct MetadataFor<commands_rtk::GetImei::Response>
             /* .name          = */ "IMEI",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::IMEI>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::IMEI>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 32,
             /* .condition     = */ {},
@@ -169,7 +169,7 @@ struct MetadataFor<commands_rtk::GetImsi::Response>
             /* .name          = */ "IMSI",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::IMSI>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::IMSI>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 32,
             /* .condition     = */ {},
@@ -215,7 +215,7 @@ struct MetadataFor<commands_rtk::GetIccid::Response>
             /* .name          = */ "ICCID",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::ICCID>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::ICCID>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 32,
             /* .condition     = */ {},
@@ -280,7 +280,7 @@ struct MetadataFor<commands_rtk::ConnectedDeviceType::Response>
             /* .name          = */ "devType",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_rtk::ConnectedDeviceType::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_rtk::ConnectedDeviceType::Type, &type::devType>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_rtk::ConnectedDeviceType::Type, &type::devType>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -310,7 +310,7 @@ struct MetadataFor<commands_rtk::ConnectedDeviceType>
             /* .name          = */ "devType",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_rtk::ConnectedDeviceType::Type>::value},
-            /* .accessor      = */ utils::access<type, commands_rtk::ConnectedDeviceType::Type, &type::devType>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_rtk::ConnectedDeviceType::Type, &type::devType>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -339,7 +339,7 @@ struct MetadataFor<commands_rtk::GetActCode::Response>
             /* .name          = */ "ActivationCode",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::ActivationCode>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::ActivationCode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 32,
             /* .condition     = */ {},
@@ -385,7 +385,7 @@ struct MetadataFor<commands_rtk::GetModemFirmwareVersion::Response>
             /* .name          = */ "ModemFirmwareVersion",
             /* .docs          = */ "",
             /* .type          = */ {Type::CHAR, nullptr},
-            /* .accessor      = */ utils::access<type, char, &type::ModemFirmwareVersion>,
+            /* .accessor      = */ nullptr, //utils::access<type, char, &type::ModemFirmwareVersion>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 32,
             /* .condition     = */ {},
@@ -431,7 +431,7 @@ struct MetadataFor<commands_rtk::GetRssi::Response>
             /* .name          = */ "valid",
             /* .docs          = */ "",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::valid>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::valid>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -440,7 +440,7 @@ struct MetadataFor<commands_rtk::GetRssi::Response>
             /* .name          = */ "rssi",
             /* .docs          = */ "",
             /* .type          = */ {Type::S32, nullptr},
-            /* .accessor      = */ utils::access<type, int32_t, &type::rssi>,
+            /* .accessor      = */ nullptr, //utils::access<type, int32_t, &type::rssi>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -449,7 +449,7 @@ struct MetadataFor<commands_rtk::GetRssi::Response>
             /* .name          = */ "signalQuality",
             /* .docs          = */ "",
             /* .type          = */ {Type::S32, nullptr},
-            /* .accessor      = */ utils::access<type, int32_t, &type::signalQuality>,
+            /* .accessor      = */ nullptr, //utils::access<type, int32_t, &type::signalQuality>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -515,7 +515,7 @@ struct MetadataFor<commands_rtk::ServiceStatus::Response>
             /* .name          = */ "flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<commands_rtk::ServiceStatus::ServiceFlags>::value},
-            /* .accessor      = */ utils::access<type, commands_rtk::ServiceStatus::ServiceFlags, &type::flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_rtk::ServiceStatus::ServiceFlags, &type::flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -524,7 +524,7 @@ struct MetadataFor<commands_rtk::ServiceStatus::Response>
             /* .name          = */ "receivedBytes",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::receivedBytes>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::receivedBytes>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -533,7 +533,7 @@ struct MetadataFor<commands_rtk::ServiceStatus::Response>
             /* .name          = */ "lastBytes",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::lastBytes>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::lastBytes>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -542,7 +542,7 @@ struct MetadataFor<commands_rtk::ServiceStatus::Response>
             /* .name          = */ "lastBytesTime",
             /* .docs          = */ "",
             /* .type          = */ {Type::U64, nullptr},
-            /* .accessor      = */ utils::access<type, uint64_t, &type::lastBytesTime>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint64_t, &type::lastBytesTime>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -571,7 +571,7 @@ struct MetadataFor<commands_rtk::ServiceStatus>
             /* .name          = */ "reserved1",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::reserved1>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::reserved1>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -580,7 +580,7 @@ struct MetadataFor<commands_rtk::ServiceStatus>
             /* .name          = */ "reserved2",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::reserved2>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::reserved2>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -628,7 +628,7 @@ struct MetadataFor<commands_rtk::ProdEraseStorage>
             /* .name          = */ "media",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_rtk::MediaSelector>::value},
-            /* .accessor      = */ utils::access<type, commands_rtk::MediaSelector, &type::media>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_rtk::MediaSelector, &type::media>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -677,7 +677,7 @@ struct MetadataFor<commands_rtk::LedControl>
             /* .name          = */ "primaryColor",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::primaryColor>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::primaryColor>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 3,
             /* .condition     = */ {},
@@ -686,7 +686,7 @@ struct MetadataFor<commands_rtk::LedControl>
             /* .name          = */ "altColor",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::altColor>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::altColor>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 3,
             /* .condition     = */ {},
@@ -695,7 +695,7 @@ struct MetadataFor<commands_rtk::LedControl>
             /* .name          = */ "act",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<commands_rtk::LedAction>::value},
-            /* .accessor      = */ utils::access<type, commands_rtk::LedAction, &type::act>,
+            /* .accessor      = */ nullptr, //utils::access<type, commands_rtk::LedAction, &type::act>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -704,7 +704,7 @@ struct MetadataFor<commands_rtk::LedControl>
             /* .name          = */ "period",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::period>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::period>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/commands_system.hpp b/src/cpp/mip/metadata/definitions/commands_system.hpp
index 559b30fd..1c3352eb 100644
--- a/src/cpp/mip/metadata/definitions/commands_system.hpp
+++ b/src/cpp/mip/metadata/definitions/commands_system.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<commands_system::CommMode::Response>
             /* .name          = */ "mode",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -50,7 +50,7 @@ struct MetadataFor<commands_system::CommMode>
             /* .name          = */ "mode",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/data_filter.hpp b/src/cpp/mip/metadata/definitions/data_filter.hpp
index 09e7e841..59935548 100644
--- a/src/cpp/mip/metadata/definitions/data_filter.hpp
+++ b/src/cpp/mip/metadata/definitions/data_filter.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<data_filter::PositionLlh>
             /* .name          = */ "latitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::latitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::latitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -29,7 +29,7 @@ struct MetadataFor<data_filter::PositionLlh>
             /* .name          = */ "longitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::longitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::longitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -38,7 +38,7 @@ struct MetadataFor<data_filter::PositionLlh>
             /* .name          = */ "ellipsoid_height",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::ellipsoid_height>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::ellipsoid_height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -47,7 +47,7 @@ struct MetadataFor<data_filter::PositionLlh>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - Invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -76,7 +76,7 @@ struct MetadataFor<data_filter::VelocityNed>
             /* .name          = */ "north",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::north>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::north>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -85,7 +85,7 @@ struct MetadataFor<data_filter::VelocityNed>
             /* .name          = */ "east",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::east>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::east>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -94,7 +94,7 @@ struct MetadataFor<data_filter::VelocityNed>
             /* .name          = */ "down",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::down>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::down>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -103,7 +103,7 @@ struct MetadataFor<data_filter::VelocityNed>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - Invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -132,7 +132,7 @@ struct MetadataFor<data_filter::AttitudeQuaternion>
             /* .name          = */ "q",
             /* .docs          = */ "Quaternion elements EQSTART q = (q_w, q_x, q_y, q_z) EQEND",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::q>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::q>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -141,7 +141,7 @@ struct MetadataFor<data_filter::AttitudeQuaternion>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -170,7 +170,7 @@ struct MetadataFor<data_filter::AttitudeDcm>
             /* .name          = */ "dcm",
             /* .docs          = */ "Matrix elements in row-major order.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::dcm>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::dcm>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -179,7 +179,7 @@ struct MetadataFor<data_filter::AttitudeDcm>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -208,7 +208,7 @@ struct MetadataFor<data_filter::EulerAngles>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -217,7 +217,7 @@ struct MetadataFor<data_filter::EulerAngles>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -226,7 +226,7 @@ struct MetadataFor<data_filter::EulerAngles>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -235,7 +235,7 @@ struct MetadataFor<data_filter::EulerAngles>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -264,7 +264,7 @@ struct MetadataFor<data_filter::GyroBias>
             /* .name          = */ "bias",
             /* .docs          = */ "(x, y, z) [radians/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -273,7 +273,7 @@ struct MetadataFor<data_filter::GyroBias>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -302,7 +302,7 @@ struct MetadataFor<data_filter::AccelBias>
             /* .name          = */ "bias",
             /* .docs          = */ "(x, y, z) [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -311,7 +311,7 @@ struct MetadataFor<data_filter::AccelBias>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -340,7 +340,7 @@ struct MetadataFor<data_filter::PositionLlhUncertainty>
             /* .name          = */ "north",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::north>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::north>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -349,7 +349,7 @@ struct MetadataFor<data_filter::PositionLlhUncertainty>
             /* .name          = */ "east",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::east>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::east>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -358,7 +358,7 @@ struct MetadataFor<data_filter::PositionLlhUncertainty>
             /* .name          = */ "down",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::down>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::down>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -367,7 +367,7 @@ struct MetadataFor<data_filter::PositionLlhUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -396,7 +396,7 @@ struct MetadataFor<data_filter::VelocityNedUncertainty>
             /* .name          = */ "north",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::north>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::north>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -405,7 +405,7 @@ struct MetadataFor<data_filter::VelocityNedUncertainty>
             /* .name          = */ "east",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::east>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::east>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -414,7 +414,7 @@ struct MetadataFor<data_filter::VelocityNedUncertainty>
             /* .name          = */ "down",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::down>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::down>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -423,7 +423,7 @@ struct MetadataFor<data_filter::VelocityNedUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -452,7 +452,7 @@ struct MetadataFor<data_filter::EulerAnglesUncertainty>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -461,7 +461,7 @@ struct MetadataFor<data_filter::EulerAnglesUncertainty>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -470,7 +470,7 @@ struct MetadataFor<data_filter::EulerAnglesUncertainty>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -479,7 +479,7 @@ struct MetadataFor<data_filter::EulerAnglesUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -508,7 +508,7 @@ struct MetadataFor<data_filter::GyroBiasUncertainty>
             /* .name          = */ "bias_uncert",
             /* .docs          = */ "(x,y,z) [radians/sec]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -517,7 +517,7 @@ struct MetadataFor<data_filter::GyroBiasUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -546,7 +546,7 @@ struct MetadataFor<data_filter::AccelBiasUncertainty>
             /* .name          = */ "bias_uncert",
             /* .docs          = */ "(x,y,z) [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -555,7 +555,7 @@ struct MetadataFor<data_filter::AccelBiasUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -584,7 +584,7 @@ struct MetadataFor<data_filter::Timestamp>
             /* .name          = */ "tow",
             /* .docs          = */ "GPS Time of Week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tow>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tow>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -593,7 +593,7 @@ struct MetadataFor<data_filter::Timestamp>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week Number since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -602,7 +602,7 @@ struct MetadataFor<data_filter::Timestamp>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -722,7 +722,7 @@ struct MetadataFor<data_filter::Status>
             /* .name          = */ "filter_state",
             /* .docs          = */ "Device-specific filter state.  Please consult the user manual for definition.",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_filter::FilterMode>::value},
-            /* .accessor      = */ utils::access<type, data_filter::FilterMode, &type::filter_state>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::FilterMode, &type::filter_state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -731,7 +731,7 @@ struct MetadataFor<data_filter::Status>
             /* .name          = */ "dynamics_mode",
             /* .docs          = */ "Device-specific dynamics mode. Please consult the user manual for definition.",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_filter::FilterDynamicsMode>::value},
-            /* .accessor      = */ utils::access<type, data_filter::FilterDynamicsMode, &type::dynamics_mode>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::FilterDynamicsMode, &type::dynamics_mode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -740,7 +740,7 @@ struct MetadataFor<data_filter::Status>
             /* .name          = */ "status_flags",
             /* .docs          = */ "Device-specific status flags.  Please consult the user manual for definition.",
             /* .type          = */ {Type::BITS, &MetadataFor<data_filter::FilterStatusFlags>::value},
-            /* .accessor      = */ utils::access<type, data_filter::FilterStatusFlags, &type::status_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::FilterStatusFlags, &type::status_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -769,7 +769,7 @@ struct MetadataFor<data_filter::LinearAccel>
             /* .name          = */ "accel",
             /* .docs          = */ "(x,y,z) [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::accel>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::accel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -778,7 +778,7 @@ struct MetadataFor<data_filter::LinearAccel>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -807,7 +807,7 @@ struct MetadataFor<data_filter::GravityVector>
             /* .name          = */ "gravity",
             /* .docs          = */ "(x, y, z) [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::gravity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::gravity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -816,7 +816,7 @@ struct MetadataFor<data_filter::GravityVector>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -845,7 +845,7 @@ struct MetadataFor<data_filter::CompAccel>
             /* .name          = */ "accel",
             /* .docs          = */ "(x,y,z) [meters/second^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::accel>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::accel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -854,7 +854,7 @@ struct MetadataFor<data_filter::CompAccel>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -883,7 +883,7 @@ struct MetadataFor<data_filter::CompAngularRate>
             /* .name          = */ "gyro",
             /* .docs          = */ "(x, y, z) [radians/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::gyro>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::gyro>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -892,7 +892,7 @@ struct MetadataFor<data_filter::CompAngularRate>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -921,7 +921,7 @@ struct MetadataFor<data_filter::QuaternionAttitudeUncertainty>
             /* .name          = */ "q",
             /* .docs          = */ "[dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::q>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::q>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -930,7 +930,7 @@ struct MetadataFor<data_filter::QuaternionAttitudeUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -959,7 +959,7 @@ struct MetadataFor<data_filter::Wgs84GravityMag>
             /* .name          = */ "magnitude",
             /* .docs          = */ "[meters/second^2]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::magnitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::magnitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -968,7 +968,7 @@ struct MetadataFor<data_filter::Wgs84GravityMag>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1019,7 +1019,7 @@ struct MetadataFor<data_filter::HeadingUpdateState>
             /* .name          = */ "heading",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1028,7 +1028,7 @@ struct MetadataFor<data_filter::HeadingUpdateState>
             /* .name          = */ "heading_1sigma",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_1sigma>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_1sigma>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1037,7 +1037,7 @@ struct MetadataFor<data_filter::HeadingUpdateState>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_filter::HeadingUpdateState::HeadingSource>::value},
-            /* .accessor      = */ utils::access<type, data_filter::HeadingUpdateState::HeadingSource, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::HeadingUpdateState::HeadingSource, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1046,7 +1046,7 @@ struct MetadataFor<data_filter::HeadingUpdateState>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "1 if a valid heading update was received in 2 seconds, 0 otherwise.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1075,7 +1075,7 @@ struct MetadataFor<data_filter::MagneticModel>
             /* .name          = */ "intensity_north",
             /* .docs          = */ "[Gauss]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::intensity_north>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::intensity_north>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1084,7 +1084,7 @@ struct MetadataFor<data_filter::MagneticModel>
             /* .name          = */ "intensity_east",
             /* .docs          = */ "[Gauss]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::intensity_east>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::intensity_east>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1093,7 +1093,7 @@ struct MetadataFor<data_filter::MagneticModel>
             /* .name          = */ "intensity_down",
             /* .docs          = */ "[Gauss]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::intensity_down>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::intensity_down>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1102,7 +1102,7 @@ struct MetadataFor<data_filter::MagneticModel>
             /* .name          = */ "inclination",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::inclination>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::inclination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1111,7 +1111,7 @@ struct MetadataFor<data_filter::MagneticModel>
             /* .name          = */ "declination",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::declination>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::declination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1120,7 +1120,7 @@ struct MetadataFor<data_filter::MagneticModel>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1149,7 +1149,7 @@ struct MetadataFor<data_filter::AccelScaleFactor>
             /* .name          = */ "scale_factor",
             /* .docs          = */ "(x,y,z) [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scale_factor>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scale_factor>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1158,7 +1158,7 @@ struct MetadataFor<data_filter::AccelScaleFactor>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1187,7 +1187,7 @@ struct MetadataFor<data_filter::AccelScaleFactorUncertainty>
             /* .name          = */ "scale_factor_uncert",
             /* .docs          = */ "(x,y,z) [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scale_factor_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scale_factor_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1196,7 +1196,7 @@ struct MetadataFor<data_filter::AccelScaleFactorUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1225,7 +1225,7 @@ struct MetadataFor<data_filter::GyroScaleFactor>
             /* .name          = */ "scale_factor",
             /* .docs          = */ "(x,y,z) [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scale_factor>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scale_factor>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1234,7 +1234,7 @@ struct MetadataFor<data_filter::GyroScaleFactor>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1263,7 +1263,7 @@ struct MetadataFor<data_filter::GyroScaleFactorUncertainty>
             /* .name          = */ "scale_factor_uncert",
             /* .docs          = */ "(x,y,z) [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scale_factor_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scale_factor_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1272,7 +1272,7 @@ struct MetadataFor<data_filter::GyroScaleFactorUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1301,7 +1301,7 @@ struct MetadataFor<data_filter::MagBias>
             /* .name          = */ "bias",
             /* .docs          = */ "(x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1310,7 +1310,7 @@ struct MetadataFor<data_filter::MagBias>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1339,7 +1339,7 @@ struct MetadataFor<data_filter::MagBiasUncertainty>
             /* .name          = */ "bias_uncert",
             /* .docs          = */ "(x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::bias_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::bias_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1348,7 +1348,7 @@ struct MetadataFor<data_filter::MagBiasUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1377,7 +1377,7 @@ struct MetadataFor<data_filter::StandardAtmosphere>
             /* .name          = */ "geometric_altitude",
             /* .docs          = */ "Input into calculation [meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::geometric_altitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::geometric_altitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1386,7 +1386,7 @@ struct MetadataFor<data_filter::StandardAtmosphere>
             /* .name          = */ "geopotential_altitude",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::geopotential_altitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::geopotential_altitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1395,7 +1395,7 @@ struct MetadataFor<data_filter::StandardAtmosphere>
             /* .name          = */ "standard_temperature",
             /* .docs          = */ "[degC]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::standard_temperature>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::standard_temperature>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1404,7 +1404,7 @@ struct MetadataFor<data_filter::StandardAtmosphere>
             /* .name          = */ "standard_pressure",
             /* .docs          = */ "[milliBar]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::standard_pressure>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::standard_pressure>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1413,7 +1413,7 @@ struct MetadataFor<data_filter::StandardAtmosphere>
             /* .name          = */ "standard_density",
             /* .docs          = */ "[kilogram/meter^3]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::standard_density>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::standard_density>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1422,7 +1422,7 @@ struct MetadataFor<data_filter::StandardAtmosphere>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1451,7 +1451,7 @@ struct MetadataFor<data_filter::PressureAltitude>
             /* .name          = */ "pressure_altitude",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pressure_altitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pressure_altitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1460,7 +1460,7 @@ struct MetadataFor<data_filter::PressureAltitude>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1489,7 +1489,7 @@ struct MetadataFor<data_filter::DensityAltitude>
             /* .name          = */ "density_altitude",
             /* .docs          = */ "m",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::density_altitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::density_altitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1498,7 +1498,7 @@ struct MetadataFor<data_filter::DensityAltitude>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1527,7 +1527,7 @@ struct MetadataFor<data_filter::AntennaOffsetCorrection>
             /* .name          = */ "offset",
             /* .docs          = */ "(x,y,z) [meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1536,7 +1536,7 @@ struct MetadataFor<data_filter::AntennaOffsetCorrection>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1565,7 +1565,7 @@ struct MetadataFor<data_filter::AntennaOffsetCorrectionUncertainty>
             /* .name          = */ "offset_uncert",
             /* .docs          = */ "(x,y,z) [meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1574,7 +1574,7 @@ struct MetadataFor<data_filter::AntennaOffsetCorrectionUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1603,7 +1603,7 @@ struct MetadataFor<data_filter::MultiAntennaOffsetCorrection>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "Receiver ID for the receiver to which the antenna is attached",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1612,7 +1612,7 @@ struct MetadataFor<data_filter::MultiAntennaOffsetCorrection>
             /* .name          = */ "offset",
             /* .docs          = */ "(x,y,z) [meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1621,7 +1621,7 @@ struct MetadataFor<data_filter::MultiAntennaOffsetCorrection>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1650,7 +1650,7 @@ struct MetadataFor<data_filter::MultiAntennaOffsetCorrectionUncertainty>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "Receiver ID for the receiver to which the antenna is attached",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1659,7 +1659,7 @@ struct MetadataFor<data_filter::MultiAntennaOffsetCorrectionUncertainty>
             /* .name          = */ "offset_uncert",
             /* .docs          = */ "(x,y,z) [meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::offset_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::offset_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1668,7 +1668,7 @@ struct MetadataFor<data_filter::MultiAntennaOffsetCorrectionUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1697,7 +1697,7 @@ struct MetadataFor<data_filter::MagnetometerOffset>
             /* .name          = */ "hard_iron",
             /* .docs          = */ "(x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::hard_iron>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::hard_iron>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1706,7 +1706,7 @@ struct MetadataFor<data_filter::MagnetometerOffset>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1735,7 +1735,7 @@ struct MetadataFor<data_filter::MagnetometerMatrix>
             /* .name          = */ "soft_iron",
             /* .docs          = */ "Row-major [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::soft_iron>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::soft_iron>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1744,7 +1744,7 @@ struct MetadataFor<data_filter::MagnetometerMatrix>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1773,7 +1773,7 @@ struct MetadataFor<data_filter::MagnetometerOffsetUncertainty>
             /* .name          = */ "hard_iron_uncertainty",
             /* .docs          = */ "(x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::hard_iron_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::hard_iron_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1782,7 +1782,7 @@ struct MetadataFor<data_filter::MagnetometerOffsetUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1811,7 +1811,7 @@ struct MetadataFor<data_filter::MagnetometerMatrixUncertainty>
             /* .name          = */ "soft_iron_uncertainty",
             /* .docs          = */ "Row-major [dimensionless]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::soft_iron_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::soft_iron_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1820,7 +1820,7 @@ struct MetadataFor<data_filter::MagnetometerMatrixUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1849,7 +1849,7 @@ struct MetadataFor<data_filter::MagnetometerCovarianceMatrix>
             /* .name          = */ "covariance",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::covariance>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::covariance>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1858,7 +1858,7 @@ struct MetadataFor<data_filter::MagnetometerCovarianceMatrix>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1887,7 +1887,7 @@ struct MetadataFor<data_filter::MagnetometerResidualVector>
             /* .name          = */ "residual",
             /* .docs          = */ "(x,y,z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::residual>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::residual>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1896,7 +1896,7 @@ struct MetadataFor<data_filter::MagnetometerResidualVector>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1925,7 +1925,7 @@ struct MetadataFor<data_filter::ClockCorrection>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "1, 2, etc.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1934,7 +1934,7 @@ struct MetadataFor<data_filter::ClockCorrection>
             /* .name          = */ "bias",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1943,7 +1943,7 @@ struct MetadataFor<data_filter::ClockCorrection>
             /* .name          = */ "bias_drift",
             /* .docs          = */ "[seconds/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::bias_drift>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::bias_drift>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1952,7 +1952,7 @@ struct MetadataFor<data_filter::ClockCorrection>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1981,7 +1981,7 @@ struct MetadataFor<data_filter::ClockCorrectionUncertainty>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "1, 2, etc.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1990,7 +1990,7 @@ struct MetadataFor<data_filter::ClockCorrectionUncertainty>
             /* .name          = */ "bias_uncertainty",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::bias_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::bias_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1999,7 +1999,7 @@ struct MetadataFor<data_filter::ClockCorrectionUncertainty>
             /* .name          = */ "bias_drift_uncertainty",
             /* .docs          = */ "[seconds/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::bias_drift_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::bias_drift_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2008,7 +2008,7 @@ struct MetadataFor<data_filter::ClockCorrectionUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2070,7 +2070,7 @@ struct MetadataFor<data_filter::GnssPosAidStatus>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2079,7 +2079,7 @@ struct MetadataFor<data_filter::GnssPosAidStatus>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "Last GNSS aiding measurement time of week [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2088,7 +2088,7 @@ struct MetadataFor<data_filter::GnssPosAidStatus>
             /* .name          = */ "status",
             /* .docs          = */ "Aiding measurement status bitfield",
             /* .type          = */ {Type::BITS, &MetadataFor<data_filter::GnssAidStatusFlags>::value},
-            /* .accessor      = */ utils::access<type, data_filter::GnssAidStatusFlags, &type::status>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::GnssAidStatusFlags, &type::status>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2097,7 +2097,7 @@ struct MetadataFor<data_filter::GnssPosAidStatus>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 8,
             /* .condition     = */ {},
@@ -2126,7 +2126,7 @@ struct MetadataFor<data_filter::GnssAttAidStatus>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "Last valid aiding measurement time of week [seconds] [processed instead of measured?]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2135,7 +2135,7 @@ struct MetadataFor<data_filter::GnssAttAidStatus>
             /* .name          = */ "status",
             /* .docs          = */ "Last valid aiding measurement status bitfield",
             /* .type          = */ {Type::BITS, &MetadataFor<data_filter::GnssAidStatusFlags>::value},
-            /* .accessor      = */ utils::access<type, data_filter::GnssAidStatusFlags, &type::status>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::GnssAidStatusFlags, &type::status>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2144,7 +2144,7 @@ struct MetadataFor<data_filter::GnssAttAidStatus>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 8,
             /* .condition     = */ {},
@@ -2192,7 +2192,7 @@ struct MetadataFor<data_filter::HeadAidStatus>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "Last valid aiding measurement time of week [seconds] [processed instead of measured?]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2201,7 +2201,7 @@ struct MetadataFor<data_filter::HeadAidStatus>
             /* .name          = */ "type",
             /* .docs          = */ "1 - Dual antenna, 2 - External heading message (user supplied)",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_filter::HeadAidStatus::HeadingAidType>::value},
-            /* .accessor      = */ utils::access<type, data_filter::HeadAidStatus::HeadingAidType, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::HeadAidStatus::HeadingAidType, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2210,7 +2210,7 @@ struct MetadataFor<data_filter::HeadAidStatus>
             /* .name          = */ "reserved",
             /* .docs          = */ "",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 2,
             /* .condition     = */ {},
@@ -2239,7 +2239,7 @@ struct MetadataFor<data_filter::RelPosNed>
             /* .name          = */ "relative_position",
             /* .docs          = */ "[meters, NED]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::relative_position>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::relative_position>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2248,7 +2248,7 @@ struct MetadataFor<data_filter::RelPosNed>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2277,7 +2277,7 @@ struct MetadataFor<data_filter::EcefPos>
             /* .name          = */ "position_ecef",
             /* .docs          = */ "[meters, ECEF]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::position_ecef>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::position_ecef>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2286,7 +2286,7 @@ struct MetadataFor<data_filter::EcefPos>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2315,7 +2315,7 @@ struct MetadataFor<data_filter::EcefVel>
             /* .name          = */ "velocity_ecef",
             /* .docs          = */ "[meters/second, ECEF]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::velocity_ecef>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::velocity_ecef>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2324,7 +2324,7 @@ struct MetadataFor<data_filter::EcefVel>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2353,7 +2353,7 @@ struct MetadataFor<data_filter::EcefPosUncertainty>
             /* .name          = */ "pos_uncertainty",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::pos_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::pos_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2362,7 +2362,7 @@ struct MetadataFor<data_filter::EcefPosUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2391,7 +2391,7 @@ struct MetadataFor<data_filter::EcefVelUncertainty>
             /* .name          = */ "vel_uncertainty",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::vel_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::vel_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2400,7 +2400,7 @@ struct MetadataFor<data_filter::EcefVelUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2484,7 +2484,7 @@ struct MetadataFor<data_filter::AidingMeasurementSummary>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2493,7 +2493,7 @@ struct MetadataFor<data_filter::AidingMeasurementSummary>
             /* .name          = */ "source",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::source>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::source>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2502,7 +2502,7 @@ struct MetadataFor<data_filter::AidingMeasurementSummary>
             /* .name          = */ "type",
             /* .docs          = */ "(see product manual for supported types) Note: values 0x20 and above correspond to commanded aiding measurements in the 0x13 Aiding command set.",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_filter::FilterAidingMeasurementType>::value},
-            /* .accessor      = */ utils::access<type, data_filter::FilterAidingMeasurementType, &type::type>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::FilterAidingMeasurementType, &type::type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2511,7 +2511,7 @@ struct MetadataFor<data_filter::AidingMeasurementSummary>
             /* .name          = */ "indicator",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_filter::FilterMeasurementIndicator>::value},
-            /* .accessor      = */ utils::access<type, data_filter::FilterMeasurementIndicator, &type::indicator>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::FilterMeasurementIndicator, &type::indicator>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2540,7 +2540,7 @@ struct MetadataFor<data_filter::OdometerScaleFactorError>
             /* .name          = */ "scale_factor_error",
             /* .docs          = */ "[dimensionless]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::scale_factor_error>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::scale_factor_error>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2549,7 +2549,7 @@ struct MetadataFor<data_filter::OdometerScaleFactorError>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2578,7 +2578,7 @@ struct MetadataFor<data_filter::OdometerScaleFactorErrorUncertainty>
             /* .name          = */ "scale_factor_error_uncertainty",
             /* .docs          = */ "[dimensionless]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::scale_factor_error_uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::scale_factor_error_uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2587,7 +2587,7 @@ struct MetadataFor<data_filter::OdometerScaleFactorErrorUncertainty>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2656,7 +2656,7 @@ struct MetadataFor<data_filter::GnssDualAntennaStatus>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "Last dual-antenna GNSS aiding measurement time of week [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2665,7 +2665,7 @@ struct MetadataFor<data_filter::GnssDualAntennaStatus>
             /* .name          = */ "heading",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2674,7 +2674,7 @@ struct MetadataFor<data_filter::GnssDualAntennaStatus>
             /* .name          = */ "heading_unc",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_unc>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_unc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2683,7 +2683,7 @@ struct MetadataFor<data_filter::GnssDualAntennaStatus>
             /* .name          = */ "fix_type",
             /* .docs          = */ "Fix type indicator",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_filter::GnssDualAntennaStatus::FixType>::value},
-            /* .accessor      = */ utils::access<type, data_filter::GnssDualAntennaStatus::FixType, &type::fix_type>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::GnssDualAntennaStatus::FixType, &type::fix_type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2692,7 +2692,7 @@ struct MetadataFor<data_filter::GnssDualAntennaStatus>
             /* .name          = */ "status_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_filter::GnssDualAntennaStatus::DualAntennaStatusFlags>::value},
-            /* .accessor      = */ utils::access<type, data_filter::GnssDualAntennaStatus::DualAntennaStatusFlags, &type::status_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_filter::GnssDualAntennaStatus::DualAntennaStatusFlags, &type::status_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2701,7 +2701,7 @@ struct MetadataFor<data_filter::GnssDualAntennaStatus>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "0 - invalid, 1 - valid",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2730,7 +2730,7 @@ struct MetadataFor<data_filter::AidingFrameConfigError>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Frame ID for the receiver to which the antenna is attached",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2739,7 +2739,7 @@ struct MetadataFor<data_filter::AidingFrameConfigError>
             /* .name          = */ "translation",
             /* .docs          = */ "Translation config X, Y, and Z (m).",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::translation>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::translation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2748,7 +2748,7 @@ struct MetadataFor<data_filter::AidingFrameConfigError>
             /* .name          = */ "attitude",
             /* .docs          = */ "Attitude quaternion",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::attitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::attitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2777,7 +2777,7 @@ struct MetadataFor<data_filter::AidingFrameConfigErrorUncertainty>
             /* .name          = */ "frame_id",
             /* .docs          = */ "Frame ID for the receiver to which the antenna is attached",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::frame_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::frame_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2786,7 +2786,7 @@ struct MetadataFor<data_filter::AidingFrameConfigErrorUncertainty>
             /* .name          = */ "translation_unc",
             /* .docs          = */ "Translation uncertaint X, Y, and Z (m).",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::translation_unc>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::translation_unc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2795,7 +2795,7 @@ struct MetadataFor<data_filter::AidingFrameConfigErrorUncertainty>
             /* .name          = */ "attitude_unc",
             /* .docs          = */ "Attitude uncertainty, X, Y, and Z (radians).",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::attitude_unc>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::attitude_unc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/data_gnss.hpp b/src/cpp/mip/metadata/definitions/data_gnss.hpp
index 173087f1..ab0ca985 100644
--- a/src/cpp/mip/metadata/definitions/data_gnss.hpp
+++ b/src/cpp/mip/metadata/definitions/data_gnss.hpp
@@ -43,7 +43,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "latitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::latitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::latitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -52,7 +52,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "longitude",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::longitude>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::longitude>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -61,7 +61,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "ellipsoid_height",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::ellipsoid_height>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::ellipsoid_height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -70,7 +70,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "msl_height",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::msl_height>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::msl_height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -79,7 +79,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "horizontal_accuracy",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::horizontal_accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::horizontal_accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -88,7 +88,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "vertical_accuracy",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::vertical_accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::vertical_accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -97,7 +97,7 @@ struct MetadataFor<data_gnss::PosLlh>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::PosLlh::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::PosLlh::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::PosLlh::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -146,7 +146,7 @@ struct MetadataFor<data_gnss::PosEcef>
             /* .name          = */ "x",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::x>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::x>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -155,7 +155,7 @@ struct MetadataFor<data_gnss::PosEcef>
             /* .name          = */ "x_accuracy",
             /* .docs          = */ "[meters]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::x_accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::x_accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -164,7 +164,7 @@ struct MetadataFor<data_gnss::PosEcef>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::PosEcef::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::PosEcef::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::PosEcef::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -217,7 +217,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "v",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::v>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::v>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -226,7 +226,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "speed",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::speed>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::speed>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -235,7 +235,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "ground_speed",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::ground_speed>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::ground_speed>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -244,7 +244,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "heading",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -253,7 +253,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "speed_accuracy",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::speed_accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::speed_accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -262,7 +262,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "heading_accuracy",
             /* .docs          = */ "[degrees]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::heading_accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::heading_accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -271,7 +271,7 @@ struct MetadataFor<data_gnss::VelNed>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::VelNed::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::VelNed::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::VelNed::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -320,7 +320,7 @@ struct MetadataFor<data_gnss::VelEcef>
             /* .name          = */ "v",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::v>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::v>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -329,7 +329,7 @@ struct MetadataFor<data_gnss::VelEcef>
             /* .name          = */ "v_accuracy",
             /* .docs          = */ "[meters/second]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::v_accuracy>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::v_accuracy>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -338,7 +338,7 @@ struct MetadataFor<data_gnss::VelEcef>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::VelEcef::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::VelEcef::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::VelEcef::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -392,7 +392,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "gdop",
             /* .docs          = */ "Geometric DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::gdop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::gdop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -401,7 +401,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "pdop",
             /* .docs          = */ "Position DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pdop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pdop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -410,7 +410,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "hdop",
             /* .docs          = */ "Horizontal DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::hdop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::hdop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -419,7 +419,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "vdop",
             /* .docs          = */ "Vertical DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::vdop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::vdop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -428,7 +428,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "tdop",
             /* .docs          = */ "Time DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::tdop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::tdop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -437,7 +437,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "ndop",
             /* .docs          = */ "Northing DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::ndop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::ndop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -446,7 +446,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "edop",
             /* .docs          = */ "Easting DOP",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::edop>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::edop>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -455,7 +455,7 @@ struct MetadataFor<data_gnss::Dop>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::Dop::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::Dop::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::Dop::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -504,7 +504,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "year",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::year>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::year>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -513,7 +513,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "month",
             /* .docs          = */ "Month (1-12)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::month>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::month>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -522,7 +522,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "day",
             /* .docs          = */ "Day (1-31)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::day>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::day>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -531,7 +531,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "hour",
             /* .docs          = */ "Hour (0-23)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::hour>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::hour>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -540,7 +540,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "min",
             /* .docs          = */ "Minute (0-59)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::min>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::min>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -549,7 +549,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "sec",
             /* .docs          = */ "Second (0-59)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sec>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sec>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -558,7 +558,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "msec",
             /* .docs          = */ "Millisecond(0-999)",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::msec>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::msec>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -567,7 +567,7 @@ struct MetadataFor<data_gnss::UtcTime>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::UtcTime::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::UtcTime::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::UtcTime::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -616,7 +616,7 @@ struct MetadataFor<data_gnss::GpsTime>
             /* .name          = */ "tow",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tow>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tow>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -625,7 +625,7 @@ struct MetadataFor<data_gnss::GpsTime>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -634,7 +634,7 @@ struct MetadataFor<data_gnss::GpsTime>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GpsTime::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GpsTime::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GpsTime::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -684,7 +684,7 @@ struct MetadataFor<data_gnss::ClockInfo>
             /* .name          = */ "bias",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -693,7 +693,7 @@ struct MetadataFor<data_gnss::ClockInfo>
             /* .name          = */ "drift",
             /* .docs          = */ "[seconds/second]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::drift>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::drift>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -702,7 +702,7 @@ struct MetadataFor<data_gnss::ClockInfo>
             /* .name          = */ "accuracy_estimate",
             /* .docs          = */ "[seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::accuracy_estimate>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::accuracy_estimate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -711,7 +711,7 @@ struct MetadataFor<data_gnss::ClockInfo>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::ClockInfo::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::ClockInfo::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::ClockInfo::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -805,7 +805,7 @@ struct MetadataFor<data_gnss::FixInfo>
             /* .name          = */ "fix_type",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::FixInfo::FixType>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::FixInfo::FixType, &type::fix_type>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::FixInfo::FixType, &type::fix_type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -814,7 +814,7 @@ struct MetadataFor<data_gnss::FixInfo>
             /* .name          = */ "num_sv",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::num_sv>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::num_sv>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -823,7 +823,7 @@ struct MetadataFor<data_gnss::FixInfo>
             /* .name          = */ "fix_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::FixInfo::FixFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::FixInfo::FixFlags, &type::fix_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::FixInfo::FixFlags, &type::fix_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -832,7 +832,7 @@ struct MetadataFor<data_gnss::FixInfo>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::FixInfo::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::FixInfo::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::FixInfo::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -904,7 +904,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "channel",
             /* .docs          = */ "Receiver channel number",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::channel>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::channel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -913,7 +913,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "sv_id",
             /* .docs          = */ "GNSS Satellite ID",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sv_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sv_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -922,7 +922,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "carrier_noise_ratio",
             /* .docs          = */ "[dBHz]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::carrier_noise_ratio>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::carrier_noise_ratio>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -931,7 +931,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "azimuth",
             /* .docs          = */ "[deg]",
             /* .type          = */ {Type::S16, nullptr},
-            /* .accessor      = */ utils::access<type, int16_t, &type::azimuth>,
+            /* .accessor      = */ nullptr, //utils::access<type, int16_t, &type::azimuth>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -940,7 +940,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "elevation",
             /* .docs          = */ "[deg]",
             /* .type          = */ {Type::S16, nullptr},
-            /* .accessor      = */ utils::access<type, int16_t, &type::elevation>,
+            /* .accessor      = */ nullptr, //utils::access<type, int16_t, &type::elevation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -949,7 +949,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "sv_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::SvInfo::SVFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SvInfo::SVFlags, &type::sv_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SvInfo::SVFlags, &type::sv_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -958,7 +958,7 @@ struct MetadataFor<data_gnss::SvInfo>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::SvInfo::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SvInfo::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SvInfo::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1070,7 +1070,7 @@ struct MetadataFor<data_gnss::HwStatus>
             /* .name          = */ "receiver_state",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::HwStatus::ReceiverState>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::HwStatus::ReceiverState, &type::receiver_state>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::HwStatus::ReceiverState, &type::receiver_state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1079,7 +1079,7 @@ struct MetadataFor<data_gnss::HwStatus>
             /* .name          = */ "antenna_state",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::HwStatus::AntennaState>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::HwStatus::AntennaState, &type::antenna_state>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::HwStatus::AntennaState, &type::antenna_state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1088,7 +1088,7 @@ struct MetadataFor<data_gnss::HwStatus>
             /* .name          = */ "antenna_power",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::HwStatus::AntennaPower>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::HwStatus::AntennaPower, &type::antenna_power>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::HwStatus::AntennaPower, &type::antenna_power>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1097,7 +1097,7 @@ struct MetadataFor<data_gnss::HwStatus>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::HwStatus::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::HwStatus::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::HwStatus::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1148,7 +1148,7 @@ struct MetadataFor<data_gnss::DgpsInfo>
             /* .name          = */ "sv_id",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sv_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sv_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1157,7 +1157,7 @@ struct MetadataFor<data_gnss::DgpsInfo>
             /* .name          = */ "age",
             /* .docs          = */ "",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::age>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::age>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1166,7 +1166,7 @@ struct MetadataFor<data_gnss::DgpsInfo>
             /* .name          = */ "range_correction",
             /* .docs          = */ "",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::range_correction>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::range_correction>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1175,7 +1175,7 @@ struct MetadataFor<data_gnss::DgpsInfo>
             /* .name          = */ "range_rate_correction",
             /* .docs          = */ "",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::range_rate_correction>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::range_rate_correction>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1184,7 +1184,7 @@ struct MetadataFor<data_gnss::DgpsInfo>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::DgpsInfo::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::DgpsInfo::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::DgpsInfo::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1235,7 +1235,7 @@ struct MetadataFor<data_gnss::DgpsChannel>
             /* .name          = */ "sv_id",
             /* .docs          = */ "",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sv_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sv_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1244,7 +1244,7 @@ struct MetadataFor<data_gnss::DgpsChannel>
             /* .name          = */ "age",
             /* .docs          = */ "[s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::age>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::age>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1253,7 +1253,7 @@ struct MetadataFor<data_gnss::DgpsChannel>
             /* .name          = */ "range_correction",
             /* .docs          = */ "[m]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::range_correction>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::range_correction>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1262,7 +1262,7 @@ struct MetadataFor<data_gnss::DgpsChannel>
             /* .name          = */ "range_rate_correction",
             /* .docs          = */ "[m/s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::range_rate_correction>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::range_rate_correction>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1271,7 +1271,7 @@ struct MetadataFor<data_gnss::DgpsChannel>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::DgpsChannel::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::DgpsChannel::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::DgpsChannel::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1322,7 +1322,7 @@ struct MetadataFor<data_gnss::ClockInfo2>
             /* .name          = */ "bias",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::bias>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::bias>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1331,7 +1331,7 @@ struct MetadataFor<data_gnss::ClockInfo2>
             /* .name          = */ "drift",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::drift>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::drift>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1340,7 +1340,7 @@ struct MetadataFor<data_gnss::ClockInfo2>
             /* .name          = */ "bias_accuracy_estimate",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::bias_accuracy_estimate>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::bias_accuracy_estimate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1349,7 +1349,7 @@ struct MetadataFor<data_gnss::ClockInfo2>
             /* .name          = */ "drift_accuracy_estimate",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::drift_accuracy_estimate>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::drift_accuracy_estimate>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1358,7 +1358,7 @@ struct MetadataFor<data_gnss::ClockInfo2>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::ClockInfo2::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::ClockInfo2::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::ClockInfo2::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1405,7 +1405,7 @@ struct MetadataFor<data_gnss::GpsLeapSeconds>
             /* .name          = */ "leap_seconds",
             /* .docs          = */ "[s]",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::leap_seconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::leap_seconds>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1414,7 +1414,7 @@ struct MetadataFor<data_gnss::GpsLeapSeconds>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GpsLeapSeconds::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GpsLeapSeconds::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GpsLeapSeconds::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1510,7 +1510,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1519,7 +1519,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1528,7 +1528,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "sbas_system",
             /* .docs          = */ "SBAS system id",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::SbasSystem>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SbasSystem, &type::sbas_system>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SbasSystem, &type::sbas_system>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1537,7 +1537,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "sbas_id",
             /* .docs          = */ "SBAS satellite id.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sbas_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sbas_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1546,7 +1546,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "count",
             /* .docs          = */ "Number of SBAS corrections",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1555,7 +1555,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "sbas_status",
             /* .docs          = */ "Status of the SBAS service",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::SbasInfo::SbasStatus>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SbasInfo::SbasStatus, &type::sbas_status>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SbasInfo::SbasStatus, &type::sbas_status>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1564,7 +1564,7 @@ struct MetadataFor<data_gnss::SbasInfo>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::SbasInfo::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SbasInfo::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SbasInfo::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1637,7 +1637,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "index",
             /* .docs          = */ "Index of this field in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::index>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::index>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1646,7 +1646,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "count",
             /* .docs          = */ "Total number of fields in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1655,7 +1655,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week the message was received [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1664,7 +1664,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1673,7 +1673,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "gnss_id",
             /* .docs          = */ "GNSS constellation id",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::GnssConstellationId>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GnssConstellationId, &type::gnss_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GnssConstellationId, &type::gnss_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1682,7 +1682,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "sv_id",
             /* .docs          = */ "GNSS satellite id within the constellation.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sv_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sv_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1691,7 +1691,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "udrei",
             /* .docs          = */ "[See above 0-13 usable, 14 not monitored, 15 - do not use]",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::udrei>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::udrei>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1700,7 +1700,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "pseudorange_correction",
             /* .docs          = */ "Pseudo-range correction [meters].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pseudorange_correction>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pseudorange_correction>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1709,7 +1709,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "iono_correction",
             /* .docs          = */ "Ionospheric correction [meters].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::iono_correction>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::iono_correction>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1718,7 +1718,7 @@ struct MetadataFor<data_gnss::SbasCorrection>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::SbasCorrection::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SbasCorrection::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SbasCorrection::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1831,7 +1831,7 @@ struct MetadataFor<data_gnss::RfErrorDetection>
             /* .name          = */ "rf_band",
             /* .docs          = */ "RF Band of the reported information",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::RfErrorDetection::RFBand>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::RfErrorDetection::RFBand, &type::rf_band>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::RfErrorDetection::RFBand, &type::rf_band>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1840,7 +1840,7 @@ struct MetadataFor<data_gnss::RfErrorDetection>
             /* .name          = */ "jamming_state",
             /* .docs          = */ "GNSS Jamming State (as reported by the GNSS module)",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::RfErrorDetection::JammingState>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::RfErrorDetection::JammingState, &type::jamming_state>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::RfErrorDetection::JammingState, &type::jamming_state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1849,7 +1849,7 @@ struct MetadataFor<data_gnss::RfErrorDetection>
             /* .name          = */ "spoofing_state",
             /* .docs          = */ "GNSS Spoofing State (as reported by the GNSS module)",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::RfErrorDetection::SpoofingState>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::RfErrorDetection::SpoofingState, &type::spoofing_state>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::RfErrorDetection::SpoofingState, &type::spoofing_state>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1858,7 +1858,7 @@ struct MetadataFor<data_gnss::RfErrorDetection>
             /* .name          = */ "reserved",
             /* .docs          = */ "Reserved for future use",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -1867,7 +1867,7 @@ struct MetadataFor<data_gnss::RfErrorDetection>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::RfErrorDetection::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::RfErrorDetection::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::RfErrorDetection::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1946,7 +1946,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week the message was received [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1955,7 +1955,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1964,7 +1964,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "ecef_pos",
             /* .docs          = */ "Earth-centered, Earth-fixed [m]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::ecef_pos>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::ecef_pos>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1973,7 +1973,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "height",
             /* .docs          = */ "Antenna Height above the marker used in the survey [m]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::height>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::height>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1982,7 +1982,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "station_id",
             /* .docs          = */ "Range: 0-4095",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::station_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::station_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -1991,7 +1991,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "indicators",
             /* .docs          = */ "Bitfield",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::BaseStationInfo::IndicatorFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::BaseStationInfo::IndicatorFlags, &type::indicators>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::BaseStationInfo::IndicatorFlags, &type::indicators>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2000,7 +2000,7 @@ struct MetadataFor<data_gnss::BaseStationInfo>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::BaseStationInfo::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::BaseStationInfo::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::BaseStationInfo::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2081,7 +2081,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2090,7 +2090,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2099,7 +2099,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "epoch_status",
             /* .docs          = */ "Status of the corrections received during this epoch",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::RtkCorrectionsStatus::EpochStatus>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::RtkCorrectionsStatus::EpochStatus, &type::epoch_status>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::RtkCorrectionsStatus::EpochStatus, &type::epoch_status>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2108,7 +2108,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "dongle_status",
             /* .docs          = */ "RTK Dongle Status Flags (valid only when using RTK dongle, see Get RTK Device Status Flags (0x0F,0x01) for details)",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::dongle_status>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::dongle_status>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2117,7 +2117,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "gps_correction_latency",
             /* .docs          = */ "Latency of last GPS correction [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::gps_correction_latency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::gps_correction_latency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2126,7 +2126,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "glonass_correction_latency",
             /* .docs          = */ "Latency of last GLONASS correction [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::glonass_correction_latency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::glonass_correction_latency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2135,7 +2135,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "galileo_correction_latency",
             /* .docs          = */ "Latency of last Galileo correction [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::galileo_correction_latency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::galileo_correction_latency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2144,7 +2144,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "beidou_correction_latency",
             /* .docs          = */ "Latency of last Beidou correction [seconds]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::beidou_correction_latency>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::beidou_correction_latency>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2153,7 +2153,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "reserved",
             /* .docs          = */ "Reserved for future use",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::reserved>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::reserved>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -2162,7 +2162,7 @@ struct MetadataFor<data_gnss::RtkCorrectionsStatus>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::RtkCorrectionsStatus::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::RtkCorrectionsStatus::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::RtkCorrectionsStatus::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2216,7 +2216,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "index",
             /* .docs          = */ "Index of this field in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::index>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::index>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2225,7 +2225,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "count",
             /* .docs          = */ "Total number of fields in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2234,7 +2234,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2243,7 +2243,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2252,7 +2252,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "gnss_id",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::GnssConstellationId>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GnssConstellationId, &type::gnss_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GnssConstellationId, &type::gnss_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2261,7 +2261,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "satellite_id",
             /* .docs          = */ "GNSS satellite id within the constellation",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::satellite_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::satellite_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2270,7 +2270,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "elevation",
             /* .docs          = */ "Elevation of the satellite relative to the rover [degrees]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::elevation>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::elevation>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2279,7 +2279,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "azimuth",
             /* .docs          = */ "Azimuth of the satellite relative to the rover [degrees]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::azimuth>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::azimuth>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2288,7 +2288,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "health",
             /* .docs          = */ "True if the satellite is healthy.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::health>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::health>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2297,7 +2297,7 @@ struct MetadataFor<data_gnss::SatelliteStatus>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::SatelliteStatus::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::SatelliteStatus::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::SatelliteStatus::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2466,7 +2466,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "index",
             /* .docs          = */ "Index of this field in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::index>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::index>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2475,7 +2475,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "count",
             /* .docs          = */ "Total number of fields in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2484,7 +2484,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2493,7 +2493,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2502,7 +2502,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "receiver_id",
             /* .docs          = */ "When the measurement comes from RTCM, this will be the reference station ID; otherwise, it's the receiver number (1,2,...)",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::receiver_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::receiver_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2511,7 +2511,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "tracking_channel",
             /* .docs          = */ "Channel the receiver is using to track this satellite.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::tracking_channel>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::tracking_channel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2520,7 +2520,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "gnss_id",
             /* .docs          = */ "",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::GnssConstellationId>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GnssConstellationId, &type::gnss_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GnssConstellationId, &type::gnss_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2529,7 +2529,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "satellite_id",
             /* .docs          = */ "GNSS satellite id within the constellation.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::satellite_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::satellite_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2538,7 +2538,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "signal_id",
             /* .docs          = */ "Signal identifier for the satellite.",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::GnssSignalId>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GnssSignalId, &type::signal_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GnssSignalId, &type::signal_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2547,7 +2547,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "signal_strength",
             /* .docs          = */ "Carrier to noise ratio [dBHz].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::signal_strength>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::signal_strength>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2556,7 +2556,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "quality",
             /* .docs          = */ "Indicator of signal quality.",
             /* .type          = */ {Type::ENUM, &MetadataFor<data_gnss::Raw::GnssSignalQuality>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::Raw::GnssSignalQuality, &type::quality>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::Raw::GnssSignalQuality, &type::quality>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2565,7 +2565,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "pseudorange",
             /* .docs          = */ "Pseudo-range measurement [meters].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::pseudorange>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::pseudorange>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2574,7 +2574,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "carrier_phase",
             /* .docs          = */ "Carrier phase measurement [Carrier periods].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::carrier_phase>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::carrier_phase>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2583,7 +2583,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "doppler",
             /* .docs          = */ "Measured doppler shift [Hz].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::doppler>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::doppler>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2592,7 +2592,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "range_uncert",
             /* .docs          = */ "Uncertainty of the pseudo-range measurement [m].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::range_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::range_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2601,7 +2601,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "phase_uncert",
             /* .docs          = */ "Uncertainty of the phase measurement [Carrier periods].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::phase_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::phase_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2610,7 +2610,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "doppler_uncert",
             /* .docs          = */ "Uncertainty of the measured doppler shift [Hz].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::doppler_uncert>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::doppler_uncert>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2619,7 +2619,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "lock_time",
             /* .docs          = */ "DOC\nMinimum carrier phase lock time [s].  Note: the maximum value is dependent on the receiver.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::lock_time>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::lock_time>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2628,7 +2628,7 @@ struct MetadataFor<data_gnss::Raw>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::Raw::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::Raw::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::Raw::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2678,7 +2678,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "index",
             /* .docs          = */ "Index of this field in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::index>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::index>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2687,7 +2687,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "count",
             /* .docs          = */ "Total number of fields in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2696,7 +2696,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2705,7 +2705,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2714,7 +2714,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "satellite_id",
             /* .docs          = */ "GNSS satellite id within the constellation.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::satellite_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::satellite_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2723,7 +2723,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "health",
             /* .docs          = */ "Satellite and signal health",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::health>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::health>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2732,7 +2732,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "iodc",
             /* .docs          = */ "Issue of Data Clock. This increments each time the data changes and\nrolls over at 4. It is used to make sure various raw data elements from\ndifferent sources line up correctly.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::iodc>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::iodc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2741,7 +2741,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "iode",
             /* .docs          = */ "Issue of Data Ephemeris.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::iode>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::iode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2750,7 +2750,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "t_oc",
             /* .docs          = */ "Reference time for clock data.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::t_oc>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::t_oc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2759,7 +2759,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "af0",
             /* .docs          = */ "Clock bias in [s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::af0>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::af0>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2768,7 +2768,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "af1",
             /* .docs          = */ "Clock drift in [s/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::af1>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::af1>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2777,7 +2777,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "af2",
             /* .docs          = */ "Clock drift rate in [s/s^2].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::af2>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::af2>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2786,7 +2786,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "t_gd",
             /* .docs          = */ "T Group Delay [s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::t_gd>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::t_gd>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2795,7 +2795,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "ISC_L1CA",
             /* .docs          = */ "Inter-signal correction (L1).",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::ISC_L1CA>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::ISC_L1CA>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2804,7 +2804,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "ISC_L2C",
             /* .docs          = */ "Inter-signal correction (L2, or L5 if isc_l5 flag is set).",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::ISC_L2C>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::ISC_L2C>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2813,7 +2813,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "t_oe",
             /* .docs          = */ "Reference time for ephemeris in [s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::t_oe>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::t_oe>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2822,7 +2822,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "a",
             /* .docs          = */ "Semi-major axis [m].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::a>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::a>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2831,7 +2831,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "a_dot",
             /* .docs          = */ "Semi-major axis rate [m/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::a_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::a_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2840,7 +2840,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "mean_anomaly",
             /* .docs          = */ "[rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::mean_anomaly>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::mean_anomaly>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2849,7 +2849,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "delta_mean_motion",
             /* .docs          = */ "[rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::delta_mean_motion>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::delta_mean_motion>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2858,7 +2858,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "delta_mean_motion_dot",
             /* .docs          = */ "[rad/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::delta_mean_motion_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::delta_mean_motion_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2867,7 +2867,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "eccentricity",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::eccentricity>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::eccentricity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2876,7 +2876,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "argument_of_perigee",
             /* .docs          = */ "[rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::argument_of_perigee>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::argument_of_perigee>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2885,7 +2885,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "omega",
             /* .docs          = */ "Longitude of Ascending Node [rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::omega>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::omega>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2894,7 +2894,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "omega_dot",
             /* .docs          = */ "Rate of Right Ascension [rad/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::omega_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::omega_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2903,7 +2903,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "inclination",
             /* .docs          = */ "Inclination angle [rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::inclination>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::inclination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2912,7 +2912,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "inclination_dot",
             /* .docs          = */ "Inclination angle rate of change [rad/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::inclination_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::inclination_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2921,7 +2921,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "c_ic",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_ic>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_ic>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2930,7 +2930,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "c_is",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_is>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_is>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2939,7 +2939,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "c_uc",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_uc>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_uc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2948,7 +2948,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "c_us",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_us>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_us>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2957,7 +2957,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "c_rc",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_rc>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_rc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2966,7 +2966,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "c_rs",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_rs>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_rs>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -2975,7 +2975,7 @@ struct MetadataFor<data_gnss::GpsEphemeris>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GpsEphemeris::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GpsEphemeris::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GpsEphemeris::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3025,7 +3025,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "index",
             /* .docs          = */ "Index of this field in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::index>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::index>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3034,7 +3034,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "count",
             /* .docs          = */ "Total number of fields in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3043,7 +3043,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3052,7 +3052,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3061,7 +3061,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "satellite_id",
             /* .docs          = */ "GNSS satellite id within the constellation.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::satellite_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::satellite_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3070,7 +3070,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "health",
             /* .docs          = */ "Satellite and signal health",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::health>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::health>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3079,7 +3079,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "iodc",
             /* .docs          = */ "Issue of Data Clock. This increments each time the data changes and\nrolls over at 4. It is used to make sure various raw data elements from\ndifferent sources line up correctly.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::iodc>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::iodc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3088,7 +3088,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "iode",
             /* .docs          = */ "Issue of Data Ephemeris.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::iode>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::iode>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3097,7 +3097,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "t_oc",
             /* .docs          = */ "Reference time for clock data.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::t_oc>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::t_oc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3106,7 +3106,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "af0",
             /* .docs          = */ "Clock bias in [s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::af0>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::af0>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3115,7 +3115,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "af1",
             /* .docs          = */ "Clock drift in [s/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::af1>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::af1>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3124,7 +3124,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "af2",
             /* .docs          = */ "Clock drift rate in [s/s^2].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::af2>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::af2>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3133,7 +3133,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "t_gd",
             /* .docs          = */ "T Group Delay [s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::t_gd>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::t_gd>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3142,7 +3142,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "ISC_L1CA",
             /* .docs          = */ "Inter-signal correction (L1).",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::ISC_L1CA>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::ISC_L1CA>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3151,7 +3151,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "ISC_L2C",
             /* .docs          = */ "Inter-signal correction (L2, or L5 if isc_l5 flag is set).",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::ISC_L2C>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::ISC_L2C>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3160,7 +3160,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "t_oe",
             /* .docs          = */ "Reference time for ephemeris in [s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::t_oe>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::t_oe>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3169,7 +3169,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "a",
             /* .docs          = */ "Semi-major axis [m].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::a>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::a>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3178,7 +3178,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "a_dot",
             /* .docs          = */ "Semi-major axis rate [m/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::a_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::a_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3187,7 +3187,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "mean_anomaly",
             /* .docs          = */ "[rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::mean_anomaly>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::mean_anomaly>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3196,7 +3196,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "delta_mean_motion",
             /* .docs          = */ "[rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::delta_mean_motion>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::delta_mean_motion>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3205,7 +3205,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "delta_mean_motion_dot",
             /* .docs          = */ "[rad/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::delta_mean_motion_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::delta_mean_motion_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3214,7 +3214,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "eccentricity",
             /* .docs          = */ "",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::eccentricity>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::eccentricity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3223,7 +3223,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "argument_of_perigee",
             /* .docs          = */ "[rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::argument_of_perigee>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::argument_of_perigee>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3232,7 +3232,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "omega",
             /* .docs          = */ "Longitude of Ascending Node [rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::omega>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::omega>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3241,7 +3241,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "omega_dot",
             /* .docs          = */ "Rate of Right Ascension [rad/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::omega_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::omega_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3250,7 +3250,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "inclination",
             /* .docs          = */ "Inclination angle [rad].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::inclination>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::inclination>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3259,7 +3259,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "inclination_dot",
             /* .docs          = */ "Inclination angle rate of change [rad/s].",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::inclination_dot>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::inclination_dot>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3268,7 +3268,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "c_ic",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_ic>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_ic>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3277,7 +3277,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "c_is",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_is>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_is>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3286,7 +3286,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "c_uc",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_uc>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_uc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3295,7 +3295,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "c_us",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_us>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_us>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3304,7 +3304,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "c_rc",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_rc>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_rc>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3313,7 +3313,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "c_rs",
             /* .docs          = */ "Harmonic Correction Term.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::c_rs>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::c_rs>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3322,7 +3322,7 @@ struct MetadataFor<data_gnss::GalileoEphemeris>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GalileoEphemeris::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GalileoEphemeris::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GalileoEphemeris::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3370,7 +3370,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "index",
             /* .docs          = */ "Index of this field in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::index>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::index>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3379,7 +3379,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "count",
             /* .docs          = */ "Total number of fields in this epoch.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::count>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::count>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3388,7 +3388,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3397,7 +3397,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3406,7 +3406,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "satellite_id",
             /* .docs          = */ "GNSS satellite id within the constellation.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::satellite_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::satellite_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3415,7 +3415,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "freq_number",
             /* .docs          = */ "GLONASS frequency number (-7 to 24)",
             /* .type          = */ {Type::S8, nullptr},
-            /* .accessor      = */ utils::access<type, int8_t, &type::freq_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, int8_t, &type::freq_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3424,7 +3424,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "tk",
             /* .docs          = */ "Frame start time within current day [seconds]",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::tk>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::tk>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3433,7 +3433,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "tb",
             /* .docs          = */ "Ephemeris reference time [seconds]",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::tb>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::tb>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3442,7 +3442,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "sat_type",
             /* .docs          = */ "Type of satellite (M) GLONASS = 0, GLONASS-M = 1",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::sat_type>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::sat_type>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3451,7 +3451,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "gamma",
             /* .docs          = */ "Relative deviation of carrier frequency from nominal [dimensionless]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::gamma>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::gamma>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3460,7 +3460,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "tau_n",
             /* .docs          = */ "Time correction relative to GLONASS Time [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tau_n>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tau_n>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3469,7 +3469,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "x",
             /* .docs          = */ "Satellite PE-90 position [m]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::x>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::x>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3478,7 +3478,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "v",
             /* .docs          = */ "Satellite PE-90 velocity [m/s]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::v>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::v>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3487,7 +3487,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "a",
             /* .docs          = */ "Satellite PE-90 acceleration due to perturbations [m/s^2]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::a>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::a>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3496,7 +3496,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "health",
             /* .docs          = */ "Satellite Health (Bn), Non-zero indicates satellite malfunction",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::health>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::health>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3505,7 +3505,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "P",
             /* .docs          = */ "Satellite operation mode (See GLONASS ICD)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::P>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::P>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3514,7 +3514,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "NT",
             /* .docs          = */ "Day number within a 4 year period.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::NT>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::NT>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3523,7 +3523,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "delta_tau_n",
             /* .docs          = */ "Time difference between L1 and L2[m/s]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::delta_tau_n>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::delta_tau_n>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3532,7 +3532,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "Ft",
             /* .docs          = */ "User Range Accuracy (See GLONASS ICD)",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::Ft>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::Ft>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3541,7 +3541,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "En",
             /* .docs          = */ "Age of current information [days]",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::En>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::En>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3550,7 +3550,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "P1",
             /* .docs          = */ "Time interval between adjacent values of tb [minutes]",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::P1>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::P1>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3559,7 +3559,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "P2",
             /* .docs          = */ "Oddness '1' or evenness '0' of the value of tb.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::P2>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::P2>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3568,7 +3568,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "P3",
             /* .docs          = */ "Number of satellites in almanac for this frame",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::P3>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::P3>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3577,7 +3577,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "P4",
             /* .docs          = */ "Flag indicating ephemeris parameters are present",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::P4>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::P4>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3586,7 +3586,7 @@ struct MetadataFor<data_gnss::GloEphemeris>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GloEphemeris::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GloEphemeris::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GloEphemeris::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3637,7 +3637,7 @@ struct MetadataFor<data_gnss::GpsIonoCorr>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3646,7 +3646,7 @@ struct MetadataFor<data_gnss::GpsIonoCorr>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3655,7 +3655,7 @@ struct MetadataFor<data_gnss::GpsIonoCorr>
             /* .name          = */ "alpha",
             /* .docs          = */ "Ionospheric Correction Terms.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::alpha>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::alpha>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -3664,7 +3664,7 @@ struct MetadataFor<data_gnss::GpsIonoCorr>
             /* .name          = */ "beta",
             /* .docs          = */ "Ionospheric Correction Terms.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::beta>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::beta>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -3673,7 +3673,7 @@ struct MetadataFor<data_gnss::GpsIonoCorr>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GpsIonoCorr::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GpsIonoCorr::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GpsIonoCorr::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3724,7 +3724,7 @@ struct MetadataFor<data_gnss::GalileoIonoCorr>
             /* .name          = */ "time_of_week",
             /* .docs          = */ "GPS Time of week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::time_of_week>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::time_of_week>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3733,7 +3733,7 @@ struct MetadataFor<data_gnss::GalileoIonoCorr>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3742,7 +3742,7 @@ struct MetadataFor<data_gnss::GalileoIonoCorr>
             /* .name          = */ "alpha",
             /* .docs          = */ "Coefficients for the model.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3d>::value},
-            /* .accessor      = */ utils::access<type, Vector3d, &type::alpha>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3d, &type::alpha>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3751,7 +3751,7 @@ struct MetadataFor<data_gnss::GalileoIonoCorr>
             /* .name          = */ "disturbance_flags",
             /* .docs          = */ "Region disturbance flags (bits 1-5).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::disturbance_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::disturbance_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -3760,7 +3760,7 @@ struct MetadataFor<data_gnss::GalileoIonoCorr>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_gnss::GalileoIonoCorr::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_gnss::GalileoIonoCorr::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_gnss::GalileoIonoCorr::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/data_sensor.hpp b/src/cpp/mip/metadata/definitions/data_sensor.hpp
index 84d0b6b0..344f0ebd 100644
--- a/src/cpp/mip/metadata/definitions/data_sensor.hpp
+++ b/src/cpp/mip/metadata/definitions/data_sensor.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<data_sensor::RawAccel>
             /* .name          = */ "raw_accel",
             /* .docs          = */ "Native sensor counts",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::raw_accel>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::raw_accel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -49,7 +49,7 @@ struct MetadataFor<data_sensor::RawGyro>
             /* .name          = */ "raw_gyro",
             /* .docs          = */ "Native sensor counts",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::raw_gyro>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::raw_gyro>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -78,7 +78,7 @@ struct MetadataFor<data_sensor::RawMag>
             /* .name          = */ "raw_mag",
             /* .docs          = */ "Native sensor counts",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::raw_mag>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::raw_mag>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -107,7 +107,7 @@ struct MetadataFor<data_sensor::RawPressure>
             /* .name          = */ "raw_pressure",
             /* .docs          = */ "Native sensor counts",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::raw_pressure>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::raw_pressure>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -136,7 +136,7 @@ struct MetadataFor<data_sensor::ScaledAccel>
             /* .name          = */ "scaled_accel",
             /* .docs          = */ "(x, y, z)[g]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scaled_accel>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scaled_accel>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -165,7 +165,7 @@ struct MetadataFor<data_sensor::ScaledGyro>
             /* .name          = */ "scaled_gyro",
             /* .docs          = */ "(x, y, z) [radians/second]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scaled_gyro>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scaled_gyro>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -194,7 +194,7 @@ struct MetadataFor<data_sensor::ScaledMag>
             /* .name          = */ "scaled_mag",
             /* .docs          = */ "(x, y, z) [Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::scaled_mag>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::scaled_mag>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -223,7 +223,7 @@ struct MetadataFor<data_sensor::ScaledPressure>
             /* .name          = */ "scaled_pressure",
             /* .docs          = */ "[mBar]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::scaled_pressure>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::scaled_pressure>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -252,7 +252,7 @@ struct MetadataFor<data_sensor::DeltaTheta>
             /* .name          = */ "delta_theta",
             /* .docs          = */ "(x, y, z) [radians]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::delta_theta>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::delta_theta>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -281,7 +281,7 @@ struct MetadataFor<data_sensor::DeltaVelocity>
             /* .name          = */ "delta_velocity",
             /* .docs          = */ "(x, y, z) [g*sec]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::delta_velocity>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::delta_velocity>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -310,7 +310,7 @@ struct MetadataFor<data_sensor::CompOrientationMatrix>
             /* .name          = */ "m",
             /* .docs          = */ "Matrix elements in row-major order.",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::m>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::m>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -339,7 +339,7 @@ struct MetadataFor<data_sensor::CompQuaternion>
             /* .name          = */ "q",
             /* .docs          = */ "Quaternion elements EQSTART q = (q_w, q_x, q_y, q_z) EQEND",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Quatf>::value},
-            /* .accessor      = */ utils::access<type, Quatf, &type::q>,
+            /* .accessor      = */ nullptr, //utils::access<type, Quatf, &type::q>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -368,7 +368,7 @@ struct MetadataFor<data_sensor::CompEulerAngles>
             /* .name          = */ "roll",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::roll>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::roll>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -377,7 +377,7 @@ struct MetadataFor<data_sensor::CompEulerAngles>
             /* .name          = */ "pitch",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::pitch>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::pitch>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -386,7 +386,7 @@ struct MetadataFor<data_sensor::CompEulerAngles>
             /* .name          = */ "yaw",
             /* .docs          = */ "[radians]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::yaw>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::yaw>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -415,7 +415,7 @@ struct MetadataFor<data_sensor::CompOrientationUpdateMatrix>
             /* .name          = */ "m",
             /* .docs          = */ "",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Matrix3f>::value},
-            /* .accessor      = */ utils::access<type, Matrix3f, &type::m>,
+            /* .accessor      = */ nullptr, //utils::access<type, Matrix3f, &type::m>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -444,7 +444,7 @@ struct MetadataFor<data_sensor::OrientationRawTemp>
             /* .name          = */ "raw_temp",
             /* .docs          = */ "",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::raw_temp>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::raw_temp>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 4,
             /* .condition     = */ {},
@@ -473,7 +473,7 @@ struct MetadataFor<data_sensor::InternalTimestamp>
             /* .name          = */ "counts",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::counts>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::counts>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -502,7 +502,7 @@ struct MetadataFor<data_sensor::PpsTimestamp>
             /* .name          = */ "seconds",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::seconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::seconds>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -511,7 +511,7 @@ struct MetadataFor<data_sensor::PpsTimestamp>
             /* .name          = */ "useconds",
             /* .docs          = */ "",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::useconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::useconds>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -562,7 +562,7 @@ struct MetadataFor<data_sensor::GpsTimestamp>
             /* .name          = */ "tow",
             /* .docs          = */ "GPS Time of Week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tow>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tow>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -571,7 +571,7 @@ struct MetadataFor<data_sensor::GpsTimestamp>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week Number since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -580,7 +580,7 @@ struct MetadataFor<data_sensor::GpsTimestamp>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_sensor::GpsTimestamp::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_sensor::GpsTimestamp::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_sensor::GpsTimestamp::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -609,7 +609,7 @@ struct MetadataFor<data_sensor::TemperatureAbs>
             /* .name          = */ "min_temp",
             /* .docs          = */ "[degC]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::min_temp>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::min_temp>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -618,7 +618,7 @@ struct MetadataFor<data_sensor::TemperatureAbs>
             /* .name          = */ "max_temp",
             /* .docs          = */ "[degC]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::max_temp>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::max_temp>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -627,7 +627,7 @@ struct MetadataFor<data_sensor::TemperatureAbs>
             /* .name          = */ "mean_temp",
             /* .docs          = */ "[degC]",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::mean_temp>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::mean_temp>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -656,7 +656,7 @@ struct MetadataFor<data_sensor::UpVector>
             /* .name          = */ "up",
             /* .docs          = */ "[Gs]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::up>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::up>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -685,7 +685,7 @@ struct MetadataFor<data_sensor::NorthVector>
             /* .name          = */ "north",
             /* .docs          = */ "[Gauss]",
             /* .type          = */ {Type::STRUCT, &MetadataFor<Vector3f>::value},
-            /* .accessor      = */ utils::access<type, Vector3f, &type::north>,
+            /* .accessor      = */ nullptr, //utils::access<type, Vector3f, &type::north>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -741,7 +741,7 @@ struct MetadataFor<data_sensor::OverrangeStatus>
             /* .name          = */ "status",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_sensor::OverrangeStatus::Status>::value},
-            /* .accessor      = */ utils::access<type, data_sensor::OverrangeStatus::Status, &type::status>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_sensor::OverrangeStatus::Status, &type::status>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -770,7 +770,7 @@ struct MetadataFor<data_sensor::OdometerData>
             /* .name          = */ "speed",
             /* .docs          = */ "Average speed over the time interval [m/s]. Can be negative for quadrature encoders.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::speed>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::speed>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -779,7 +779,7 @@ struct MetadataFor<data_sensor::OdometerData>
             /* .name          = */ "uncertainty",
             /* .docs          = */ "Uncertainty of velocity [m/s].",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::uncertainty>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::uncertainty>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -788,7 +788,7 @@ struct MetadataFor<data_sensor::OdometerData>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "If odometer is configured, bit 0 will be set to 1.",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/data_shared.hpp b/src/cpp/mip/metadata/definitions/data_shared.hpp
index d5016589..4122ba7d 100644
--- a/src/cpp/mip/metadata/definitions/data_shared.hpp
+++ b/src/cpp/mip/metadata/definitions/data_shared.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<data_shared::EventSource>
             /* .name          = */ "trigger_id",
             /* .docs          = */ "Trigger ID number. If 0, this message was emitted due to being\nscheduled in the 3DM Message Format Command (0x0C,0x0F).",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::trigger_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::trigger_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -49,7 +49,7 @@ struct MetadataFor<data_shared::Ticks>
             /* .name          = */ "ticks",
             /* .docs          = */ "Ticks since powerup.",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::ticks>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::ticks>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -78,7 +78,7 @@ struct MetadataFor<data_shared::DeltaTicks>
             /* .name          = */ "ticks",
             /* .docs          = */ "Ticks since last output.",
             /* .type          = */ {Type::U32, nullptr},
-            /* .accessor      = */ utils::access<type, uint32_t, &type::ticks>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint32_t, &type::ticks>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -127,7 +127,7 @@ struct MetadataFor<data_shared::GpsTimestamp>
             /* .name          = */ "tow",
             /* .docs          = */ "GPS Time of Week [seconds]",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::tow>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::tow>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -136,7 +136,7 @@ struct MetadataFor<data_shared::GpsTimestamp>
             /* .name          = */ "week_number",
             /* .docs          = */ "GPS Week Number since 1980 [weeks]",
             /* .type          = */ {Type::U16, nullptr},
-            /* .accessor      = */ utils::access<type, uint16_t, &type::week_number>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint16_t, &type::week_number>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -145,7 +145,7 @@ struct MetadataFor<data_shared::GpsTimestamp>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_shared::GpsTimestamp::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_shared::GpsTimestamp::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_shared::GpsTimestamp::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -174,7 +174,7 @@ struct MetadataFor<data_shared::DeltaTime>
             /* .name          = */ "seconds",
             /* .docs          = */ "Seconds since last output.",
             /* .type          = */ {Type::DOUBLE, nullptr},
-            /* .accessor      = */ utils::access<type, double, &type::seconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, double, &type::seconds>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -203,7 +203,7 @@ struct MetadataFor<data_shared::ReferenceTimestamp>
             /* .name          = */ "nanoseconds",
             /* .docs          = */ "Nanoseconds since initialization.",
             /* .type          = */ {Type::U64, nullptr},
-            /* .accessor      = */ utils::access<type, uint64_t, &type::nanoseconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint64_t, &type::nanoseconds>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -232,7 +232,7 @@ struct MetadataFor<data_shared::ReferenceTimeDelta>
             /* .name          = */ "dt_nanos",
             /* .docs          = */ "Nanoseconds since the last occurrence of this field in a packet of the same descriptor set and event source.",
             /* .type          = */ {Type::U64, nullptr},
-            /* .accessor      = */ utils::access<type, uint64_t, &type::dt_nanos>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint64_t, &type::dt_nanos>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -279,7 +279,7 @@ struct MetadataFor<data_shared::ExternalTimestamp>
             /* .name          = */ "nanoseconds",
             /* .docs          = */ "",
             /* .type          = */ {Type::U64, nullptr},
-            /* .accessor      = */ utils::access<type, uint64_t, &type::nanoseconds>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint64_t, &type::nanoseconds>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -288,7 +288,7 @@ struct MetadataFor<data_shared::ExternalTimestamp>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_shared::ExternalTimestamp::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_shared::ExternalTimestamp::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_shared::ExternalTimestamp::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -335,7 +335,7 @@ struct MetadataFor<data_shared::ExternalTimeDelta>
             /* .name          = */ "dt_nanos",
             /* .docs          = */ "Nanoseconds since the last occurrence of this field in a packet of the same descriptor set and event source.",
             /* .type          = */ {Type::U64, nullptr},
-            /* .accessor      = */ utils::access<type, uint64_t, &type::dt_nanos>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint64_t, &type::dt_nanos>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -344,7 +344,7 @@ struct MetadataFor<data_shared::ExternalTimeDelta>
             /* .name          = */ "valid_flags",
             /* .docs          = */ "",
             /* .type          = */ {Type::BITS, &MetadataFor<data_shared::ExternalTimeDelta::ValidFlags>::value},
-            /* .accessor      = */ utils::access<type, data_shared::ExternalTimeDelta::ValidFlags, &type::valid_flags>,
+            /* .accessor      = */ nullptr, //utils::access<type, data_shared::ExternalTimeDelta::ValidFlags, &type::valid_flags>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
diff --git a/src/cpp/mip/metadata/definitions/data_system.hpp b/src/cpp/mip/metadata/definitions/data_system.hpp
index dd382fc1..70b21cfc 100644
--- a/src/cpp/mip/metadata/definitions/data_system.hpp
+++ b/src/cpp/mip/metadata/definitions/data_system.hpp
@@ -20,7 +20,7 @@ struct MetadataFor<data_system::BuiltInTest>
             /* .name          = */ "result",
             /* .docs          = */ "Device-specific bitfield (128 bits). See device user manual.\nBits are least-significant-byte first. For example, bit 0 is\nlocated at bit 0 of result[0], bit 1 is located at bit 1 of result[0],\nbit 8 is located at bit 0 of result[1], and bit 127 is located at bit\n7 of result[15].",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::result>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::result>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 16,
             /* .condition     = */ {},
@@ -49,7 +49,7 @@ struct MetadataFor<data_system::TimeSyncStatus>
             /* .name          = */ "time_sync",
             /* .docs          = */ "True if sync with the PPS signal is currently valid. False if PPS\nfeature is disabled or a PPS signal is not detected.",
             /* .type          = */ {Type::BOOL, nullptr},
-            /* .accessor      = */ utils::access<type, bool, &type::time_sync>,
+            /* .accessor      = */ nullptr, //utils::access<type, bool, &type::time_sync>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -58,7 +58,7 @@ struct MetadataFor<data_system::TimeSyncStatus>
             /* .name          = */ "last_pps_rcvd",
             /* .docs          = */ "Elapsed time in seconds since last PPS was received, with a maximum\nvalue of 255.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::last_pps_rcvd>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::last_pps_rcvd>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -87,7 +87,7 @@ struct MetadataFor<data_system::GpioState>
             /* .name          = */ "states",
             /* .docs          = */ "Bitfield containing the states for each GPIO pin.<br/>\nBit 0 (0x01): pin 1<br/>\nBit 1 (0x02): pin 2<br/>\nBit 2 (0x04): pin 3<br/>\nBit 3 (0x08): pin 4<br/>\nBits for pins that don't exist will read as 0.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::states>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::states>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -116,7 +116,7 @@ struct MetadataFor<data_system::GpioAnalogValue>
             /* .name          = */ "gpio_id",
             /* .docs          = */ "GPIO pin number starting with 1.",
             /* .type          = */ {Type::U8, nullptr},
-            /* .accessor      = */ utils::access<type, uint8_t, &type::gpio_id>,
+            /* .accessor      = */ nullptr, //utils::access<type, uint8_t, &type::gpio_id>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},
@@ -125,7 +125,7 @@ struct MetadataFor<data_system::GpioAnalogValue>
             /* .name          = */ "value",
             /* .docs          = */ "Value of the GPIO line in scaled volts.",
             /* .type          = */ {Type::FLOAT, nullptr},
-            /* .accessor      = */ utils::access<type, float, &type::value>,
+            /* .accessor      = */ nullptr, //utils::access<type, float, &type::value>,
             /* .attributes    = */ {true, false, false, false, false},
             /* .count         = */ 1,
             /* .condition     = */ {},