05-04-2019 07:17 PM - edited 05-04-2019 07:22 PM
I was measuring voltages directly only connecting NI9207 (AI0+ and AI0-) and voltage source (+ and -), I got wrong readouts. I tested using a know voltage source and comparing multimeter value with NI-MAX task (see Ni-MAX task.JPG) for checking.
Using the configuration like wiring.JPG the problem was resolved. But I have to use a 1M resistor for each voltage channel for getting right measurements.
Is there any solution for improve this scenario? I mean avoid using 1M resitor for each voltage channel
05-06-2019 01:30 AM
You need at least one 1M (or another bias current path). All depends on your source(s), how are they related to COM?
Or: What are your sources and how are they supplied and connected related to COM of the DAQ?
(See my signature: Ground is ...)