EPICS: Key error for epuAngle device and progressive stack serialization error

[RussBerg]

Two errors from last nights testing:

Key Error with epu angle device, eventually the progressive stack fails to serialize the data before sending it to nx_server.

KeyError: 'DNM_EPU_ANGLE'
ERROR: Feb/26 16:22:40 [ophyd.objects] Subscription value callback exception (EpicsSignal(read_pv='BL1610-I10:epuAngle.LLS', name='DNM_EPU_ANGLE_at_low_limit_val', parent='DNM_EPU_ANGLE', value=0, timestamp=1772144560.050173, auto_monitor=False, string=False, write_pv='BL1610-I10:epuAngle.LLS', limits=False, put_complete=False))
Traceback (most recent call last):
  File "/home/sm-user/miniforge3/envs/pyStxm/lib/python3.11/site-packages/ophyd/ophydobj.py", line 492, in inner
    cb(*args, **kwargs)
  File "/mnt/srv-unix-home/sm-user/git_sandbox/deployed/v0-2-1/pyStxm/cls/applications/pyStxm/../../../cls/applications/pyStxm/widgets/motorPanel.py", line 740, in update_limit_le_ds
    (dev, dev_ui, widg, mtr) = self.mtr_dict[pvname]
                               ~~~~~~~~~~~~~^^^^^^^^

Serialize error:

ERROR: Feb/26 21:45:01 [cls.appWidgets.main_object] Error publishing progressive stack data to Pixeltor: Type is not JSON serializable: numpy.float64