PXIe-4340 External Excitation Support and DAQmx Error -200077

Updated Jan 3, 2020

Reported In


  • PXIe-4340


  • NI-DAQmx

Issue Details

I am trying to take LVDT measurements with my PXIe-4340. I want to use an external excitation source, but when I set the Vex Source to External in NI MAX I get Error -200077. Can I use external excitation with my PXIe-4340?
Error -200077 occurred at DAQ 
Possible Reason(s):

Requested value is not a supported value for this property. The property value may be invalid because it conflicts with another property.

Property: AI.Excit.Src 
Requested Value: External 
Possible Values: Internal 
Channel Name: LVDTPosition


Using external excitation is not possible with the PXIe-4340. This is because an LVDT operates by returning a phase offset based off of a known input signal.

Additional Information

There is no way for the PXIe-4340 to calibrate its measurements if the input signal to the LVDT is sourced from an external device. Therefore, the DAQmx driver is designed to throw an error when the AI.Excit.Src property is set to External.