Using MyRIO's Differential Analog Input as a Single Ended Input

[ghp_1]

Hi

I want to use the MyRIO's Connector C's Differential Analog Input (+-10V) as a single-ended analog input. A related previous post where this was done and resulted in a better signal to noise ratio is found here: https://forums.ni.com/t5/Real-Time-Measurement-and/myRIO-Analog-Inputs-GND-Reference-How-to-mitigate...

My question is: is it sufficient to simply connect the AI- to the MyRIO's signal ground, and connect the single ended output from the sensor I am measuring from at the AI+, or does the channel have to be configured in the MyRIO specifically for use as a single input channel?

I see for the following cRIO module, there is a configuration option: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000PAjRSAW

However I was unable to find any such configuration option in the LabVIEW project for the MyRIO

Any thoughts?

[nanocyte]

Yes, you have the basic idea down. It's not unusual though to send a differential pair out from the + and - input all the way to the sensor. It can seem like redundant wiring but it can help cancel certain forms of noise.

This guide has a picture showing you where in the project to configure the endedness https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P906SAC

[ghp_1 · Accepted solution]

Hi

Thank you for these details

The guide however is for the cRIO, and not the MyRIO. I tried looking in the project tree and couldn't find any such option for the MyRIO

Perhaps the MyRIO doesn't have such an option?

[nanocyte]

Ahh, yeah, I didn't notice that you were on MyRIO. MyRIO isn't configurable. The behavior (differential vs single ended) is fixed per pin. Check out page 8 here:

http://www.ni.com/pdf/manuals/376047c.pdf

[ikaiser]

But in general you and nanocyte are correct. If your sensor does only have a single-ended output but your input is differential, you should wire the sensors ground-reference (probably common ground or your power supply's "Minus") to the input channel's Minus.