Any ideas on what might cause an offset for just the AI- channels (and not the AI+ channels)?
We recently replaced two cables in an instrument to accommodate a different external connector type, but didn't (intentionally) change any actual connections (so I did not expect any changes when I powered up the DAQ/instrument again). However, since then, all AI- channels (but not the AI+ channels) on our USB 6343 have a ~+6.12 V offset from what is measured with a multimeter. When the rest of the instrument is powered down (with only the DAQ powered), then the AI+ and AI- channels read 0V, so the problem is somehow related to the larger system.
I see the issue with both my VI as well as in MAX. I've tried resetting, self-testing, and self-calibration (all complete successfully, but don't improve the described behavior). Affected measurements are for a variety of components (thermocouple amplifiers, pressure controllers, mass flow meters, etc).
EDIT: I also have a USB-6001 in the system, and it is unaffected by these issues (both DAQs measure the output from thermocouple amplifiers that all have the same grounding/power).
