Votage value read in VI is less than the value read at the termainal block.

[Roese]

I am using DAQmx VI's to read 32 channels from a PXI chassis with a 6071 analog input module.   The voltages showing up within the program seem to be significantly lower than when I read the voltages  directly at the terminal block using a volt meter.   For example, in one instance, I am reading 1.8 volts at the terminal block, but the program shows only 1.4 volts.

[devchander]

Plz go through and do a check on these details

Are you feeding a Pure DC Voltage level?? or are you observing some fluctuations/noise in the voltage read by DAQ.

Is it a floating or ground referenced voltage source??

What Input mode ( your card has 3 Analog input modes, RSE, NRSE, Differential) are you reading the signal in?

and have you wired the signal correctly for that mode??

are you following the connection details mentioned in 'Connecting Signals' section of the DAQ card user manual??

[Jennifer O]

Roese,

Devchandler has asked some excellent questions.  The difference you are seeing in voltages could be for a variety of reasons and verifying your connections is the best place to start.  There is a section in the E Series User Manual and Specifications called 'Connecting Analog Input Signals' which outlines the proper connections to make for the different modes (RSE, NRSE, Differential).

Also, what software are you using to take the measurements? Are you sampling a single channel or multiple channels? What is your sampling rate?

Regards,
Jennifer O.