DAQ Troubleshooting Question

[Coulton]

When I was setting up my USB 6210 I hit the run button to see what my voltage values were. Without doing anything to my DAQ assistant or touching the DAQ, the voltage inputs do this. Any ideas as to what may be causing this?

[Dennis_Knutson]

If you haven't done anything to the DAQ inputs, then there is nothing unusual. Typical for floating inputs. Apply a gnd or known voltage before you start to question what the DAQ is doing wrong.

[RavensFan]

Do what?

You've shown us two snapshots of data.  What is wrong with them?

[Mark_Ramsdale]

What does your code look like, and what is hooked up to your DAQ?  Not a lot of info, this may just be noise.

[Coulton]

My current VI is nothing but a DAQ. At one point I will have the voltage input that is in the screenshot that varies by 20+ mV and I attached a voltmeter to confirm. But then at any instant all of the inputs drop down and hover around 1.5 mV. When the inputs are at the top values the inputs float around +/- 2mV so I know that something is wrong when I have all of them drop down to 1.5 mV at the same time and they all stay there until randomly they go back up to the higher values. Let me know if you need more explaination.

[Coulton]

I have 6 wheatstone bridges attached to each input. They should theoretically read 0 V, but I understand the issue of imperfection. I really don't care if they aren't zero as long as they stay at a somewhat constant voltage (i.e. +/- 3 mV)

[Mark_Ramsdale]

Can you post the VI?   Are you saying the system voltages drop and jump randomly only after you attach the DAQ to your system?

[Dennis_Knutson]

Again, you are not explaining enough. Do you have actual signals connected or not? If not, please search about ghosting and then actually connect something. Then, only be concerned about the channels where you connected something.

[Coulton]

Yes, all 6 channels have the proper inputs connected. I have double check the voltage readings and when they are sparatic (i.e. 25 mV, -5 mV etc) they are correct.

Without doing anything (not unplugging, not moving, not doing anything at all) they voltages all drop to 1.5 mV while still attached to the voltage inputs

[Coulton]

Mark,

The VI consist of simply a DAQ assistant right now. I was making sure the USB 6210 was being read correctly by the VI. Yes, the voltages drop to 1.5 mV randomly without me doing anything at all.