Problem using NI-PCI-6703 for generating low voltages (25mV)

[marles]

Hi! I have a BIG problem with my NI-PCI-6703 board. I have to generate some low voltages (25mV) and sometimes the board works fine, other times it generates lower or higher voltages (17mV....47mV, or even bigger: 540mV etc.). Why is this happening? I'm resetting the board, my entire system but no use... Sometimes it gets to work properly... I need help, please!

[Tori_W]

Marles:

The first solution that comes to mind is to check grounding issues. The url below links to the user manual
for the PCI-6703. From Figure 2-3, make sure the AO GND is properly grounded and that your measurement
device is referencing the same ground.

https://www.ni.com/docs/en-US/bundle/pci-pxi-6703-6704-features/resource/372110d.pdf

The tutorial linked below is an excellent overview of grounding and issues that may arise in general.

https://www.ni.com/en/shop/data-acquisition/measurement-fundamentals/field-wiring-and-noise-consider...

Also, what type of measurement device are you using (handheld DMM, NI modular, etc) and are you calculating
this through LabVIEW?

Tori W.