Multifunction DAQ

cancel
Showing results for 
Search instead for 
Did you mean: 

Noisy Signal from USB 6211

I also suspect that this issue is related to a ground loop in your system. The output you are experiencing is typical of a system that is improperly wired. While it is possible, I doubt that the 6211 is broken if you just recently purchased it. It is much more likely that these signals are floating at points and causing undefined input.

 

Take a look at this guide on wiring DAQ systems. Based on quickly looking at the SR830 datasheet, it appears you have the option to select its grounding mode (virtual vs. physical). Make sure that this is configured according to the field wiring guide. For example, if you are using a virtual ground and would like to use a differential configuration in LabVIEW, you will need to add pull-down resistors between your amplifier and the 6211. Otherwise, your system will not work.

 

Furthermore, it is possible that you have a ground loop between your sensor and your amplifier. This would also cause strange output, but is unrelated to the 6211. My recommendation to you is that you verify that all of your grounds are properly wired. The goal here is to make sure that each of your devices is referencing the same ground, all in parallel. Would you mind explaining your grounding decisions and motivations for them? This is probably where your problem is arising.

 

Best,

 

Duncan W.

Message 11 of 11
(486 Views)