Do I have to specifiy Excitation Value (AI.Excit.Val) for DAQMX Channel with external excitation

[etaaron]

I am reading an accelerometer with a NI-4472 signal analyzer.  The accelerometers have there own power supply.  I have DAQmx channel set up with AI.Excit.Src set to External.  Do I have to specify AI.Excit.Val?  If I don't specify it what is the default value?

[Brandon_B]

Hello etaaron,

I'm not sure what the default is (most likely 10V), but yes you need to specify what the excitation value is because your device reads your signal input as a ratio of volts over excitation voltage.  If your program doesn't know this exciation value then your readings will be incorrectly calculated.  Please let me know if you have any additional questions.

Regards,