Using myRio to measure analog input

[bSeleb]

Hi all, 

I'm using labview 2019 with myrio toolkit to measure an analog signal +/- 10V. I'm new to labview, and I designed a simple program to read and graph an incoming waveform. Using a DC power supply to test, and using the differential A0 input on the C side. I am getting odd results with a full spectrum of noise. A screencap is attached of the aquired signal (~+1.6 V). As you can see, sometimes the reading is correct and sometimes it's wild, sometimes just wild. Could this be a bad connection? Any advice would be appreciated, not sure why this would be occuring. 

[aeastet]

What environment do you have this in? Do you have large loads anywhere around the analog input? Is the analog input shielded?

You should try to give more information on what you are doing with the RIO.

[bSeleb]

Update, sorry. This will ultimately be used to read the +/-10 V analog signal from a BNC output of an old instrumentation panel to streamline data collection. For now I'm just testing my program with a DC power supply. There are no large loads nearby, we considered that issue. But the analog input is not particularly well shielded (prototyping wires). 

[aeastet]

I would think it could be ground looping. Do you have your power supply and daq system plugged into the same circuit? If you disconnect the voltage do you still see the noise with nothing on the channel?

[bSeleb]

Yes, when I disconnect I will either see 0 V (correct) or noise between +10V and -10V