diff --git a/fygen.py b/fygen.py
index c783f79..32eb154 100644
--- a/fygen.py
+++ b/fygen.py
@@ -288,6 +288,15 @@ def __init__(
       model = self.get_model()
       self.device_name = detect_device(model)
 
+    self.frequency_includes_decimal = False
+    if self.device_name == "fy6300":
+      # Model:   FY6300-50M
+      # Version: V2.3.2
+      # Frequency must be sent with decimal for WMF/WFF commands,
+      # And RMF command is received with decimal.
+      # (e.g. frequency is always represented in the form): 12345678.901234 Hz
+      self.frequency_includes_decimal = True
+
   def close(self):
     """Closes serial port.  Call this at program exit for a clean shutdown."""
     self.port.close()
@@ -444,8 +453,8 @@ def should_set(chan, parm_name, expected_value):
     make_command = {
         'duty_cycle': functools.partial(_make_duty_cycle_command, channel),
         'enable': functools.partial(_make_enable_command, channel),
-        'freq_hz': functools.partial(_make_freq_hz_command, channel),
-        'freq_uhz': functools.partial(_make_freq_uhz_command, channel),
+        'freq_hz': functools.partial(_make_freq_hz_command, channel, include_decimal=self.frequency_includes_decimal),
+        'freq_uhz': functools.partial(_make_freq_uhz_command, channel, include_decimal=self.frequency_includes_decimal),
         'offset_volts': functools.partial(
             _make_offset_volts_command,
             channel,
@@ -1218,7 +1227,7 @@ def _make_wave_command(channel, device_name, wave):
   return _make_command(channel, 'W%02u' % wave)
 
 
-def _make_freq_uhz_command(channel, freq_uhz):
+def _make_freq_uhz_command(channel, freq_uhz, include_decimal=False):
   """Create a frequency command string.
 
   freq_hz and freq_uhz are summed for the final result.
@@ -1233,10 +1242,15 @@ def _make_freq_uhz_command(channel, freq_uhz):
   if freq_uhz < 0:
     raise InvalidFrequencyError('Invalid freq_uhz: %d' % freq_uhz)
 
-  return _make_command(channel, 'F%014u' % freq_uhz)
+  if include_decimal:
+    s = 'F%015.6f' % (freq_uhz/1e6)
+    return _make_command(channel, s)
+  else:
+    return _make_command(channel, 'F%014u' % freq_uhz)
+
 
-def _make_freq_hz_command(channel, freq_hz):
-  return _make_freq_uhz_command(channel, freq_hz * 1000000)
+def _make_freq_hz_command(channel, freq_hz, include_decimal=False):
+  return _make_freq_uhz_command(channel, freq_hz * 1000000, include_decimal=include_decimal)
 
 
 def _make_volts_command(channel, max_volts, volts):
diff --git a/fygen_test.py b/fygen_test.py
index 9024ec1..07c1e77 100644
--- a/fygen_test.py
+++ b/fygen_test.py
@@ -1090,5 +1090,38 @@ def test_autodetect_no_conflict(self):
     for device in SUPPORTED_DEVICES:
       self.assertEqual(fygen.detect_device(device), device)
 
+class TestFYGenFY6300(TestFYGen):
+  """Test harness for FY6300, which represents frequency differently in WMF/WFF command."""
+  def setUp(self):
+    self.output = six.StringIO()
+    self.fy = fygen.FYGen(
+      port=self.output,
+      init_state=False,
+      device_name='fy6300',
+    )
+
+  def tearDown(self):
+    self.fy.close()
+
+  def test_set_freq1(self):
+    """Sets a frequency using freq_hz."""
+    self.fy.set(freq_hz=5000)
+    self.fy.set(channel=1, freq_hz=1e6)
+    self.assertEqual(
+      'WMF00005000.000000\n'
+      'WFF01000000.000000\n',
+      self.output.getvalue())
+
+  def test_set_freq2(self):
+    """Sets a frequency using freq_uhz."""
+    self.fy.set(freq_uhz=5000)
+    self.fy.set(channel=1, freq_uhz=1e6)
+    self.assertEqual(
+      'WMF00000000.005000\n'
+      'WFF00000001.000000\n',
+      self.output.getvalue())
+
+
 if __name__ == '__main__':
   unittest.main()
+
diff --git a/wavedef.py b/wavedef.py
index 2423dca..b0f89e6 100644
--- a/wavedef.py
+++ b/wavedef.py
@@ -28,6 +28,7 @@ class UnsupportedDeviceError(Error):
 # mostly work anyway.
 SUPPORTED_DEVICES = set((
     'fy2300',
+    'fy6300',
     'fy6600',
     'fy6800',
     'fy6900',