Wiring Multiple Floating Differential Inputs On the NI 9205

Updated May 10, 2024

Reported In

Hardware

  • NI-9205

Issue Details

I see on page 18 of the NI 9205 getting started guide it mentions a 1MΩ resistor when connecting a floating differential input. Do I need to wire this resistor for each differential input, or can I use a single resistor for all the analog inputs?

Solution

All of the negative input channels are connected to the same common node, so you can use a single resistor to connect all the negative signals to the COM input.

Additional Information

This is the case because the resistor is intended to keep the overall single ended voltage input within the card limits. This high resistance element is intended to do this for all differential pairs connected.