negative reading with PXI6259 while positive with digital multimeter

[Eve]

Hi,

I have some trouble measuring voltages on my PXI6259.

When I measured the voltage with a digital multimeter, it shows positive reading. And I read the voltage with the multimeter directly on the pins of my connector block  when it is connected. But measuring with the PXI 6259 in my VB program using DAQmxReadAnalogF64, the measured voltage dropped down to negative.

Also I used MAX and got the negative reading just as that of VB program.


What could be the reason? Thanks for your help in advance.

Eve

[Chris_D]

Hey Eve,

Are the values you are reading the same, but just opposite in polarity? Also what is your input mode configuration (Differential, RSE, NRSE)? If you are measuring in differential you may have your leads backwards on your multimeter. Try swapping them and see if you get the correct negative reading.