My NI PCI-6071E DAQ have unusual readings on analog inputs.

[Licenio]

Hello,

I tried to input a DC voltage from a power supply to test whether my DAQ device reads an analog input signal and measures it corretly.

However, I found out that it had an unusual readings.

I used the SCB-68 as the connector block and an Agilent DC power supply.

The input voltage is +5V and the DAQ reads a sort of square waveform.

I checked it using the test panels from MAX.

Please check my attachments for the picture.

I tried to output a sine waveform with 5V amplitude at Analog output 1 and input it to Analog input 0.

The result was as expected.

Please check my attachments for the picture.

So what could be the problem?

[Neil_S.]

Licenio,

Thanks for posting to the NI forums.  I took a look at the pictures you included and have a few additional questions about your setup.  I noticed that you had the analog input terminal configuration set to NRSE when measuring from the power supply.  Where did you connect the ground from the power supply?  It should be connected to AI SENSE to get a proper reading.

For more information about wiring different types of sources to a DAQ device see:
https://www.ni.com/en/shop/data-acquisition/measurement-fundamentals/field-wiring-and-noise-consider...

Hopefully this gets you started toward a resolution.  If need further clarification or if the change in wiring does not fix the problem feel free to post back to this thread.

Good luck.

Regards,

Neil Stoddard
Applications Engineer
National Instruments