output_value for Epics output record device is only valid for analog inputs

[canismarko]

I tried to use the EpicsRecordOutputFields device to map to an EPICS 'bo' record, and received an error message telling me that there is no .OVAL PV.

This is true, since the .OVAL field is defined for the 'ao' record, but not for the 'bo' record.

Not sure what the best solution is. Maybe move the output_value attribute to a subclass of the EpicsRecordOutputFields device (e.g. EpicsRecordAnalogOutputFields(EpicsRecordOutputFields))? Alternately, just make sure it's documented that the EpicsRecordOutputFields is only for analog outputs? Or a third option?

[prjemian]

@canismarko Thanks for pointing this out.

[prjemian]

I like option 1 the best, yet might break some current implementations. Here's my search of usage in the main branch here:

(base) jemian@otz ~/.../BCDA-APS/apstools $ git grep EpicsRecordOutputFields
apstools/devices/__init__.py:from ..synApps import EpicsRecordOutputFields
apstools/synApps/__init__.py:from ._common import EpicsRecordOutputFields
apstools/synApps/_common.py:    ~EpicsRecordOutputFields
apstools/synApps/_common.py:class EpicsRecordOutputFields(Device):
docs/source/api/synApps/index.rst:   ~apstools.synApps._common.EpicsRecordOutputFields

[prjemian]

Summary with that search is that option 1 would not break existing apstools code.

[prjemian]

Checking the instrument package template, no usage there either:

(base) jemian@otz ~/.../BCDA-APS/bluesky_training $ git grep EpicsRecordOutputFields

[prjemian]

.OVAL is used specifically here:

(base) jemian@otz ~/.../BCDA-APS/apstools $ git grep OVAL
apstools/synApps/_common.py:    output_value = Component(EpicsSignal, ".OVAL", kind="normal")
apstools/synApps/calcout.py:    output_value = Cpt(EpicsSignal, ".OVAL", kind="hinted")
apstools/synApps/epid.py:    output_value = Component(EpicsSignalRO, ".OVAL", kind="config")
apstools/synApps/epid.py:    #     .LOPR <= .OVAL <= .HOPR
apstools/synApps/scalcout.py:    output_value = Cpt(EpicsSignal, ".OVAL", kind="config")