Multifunction DAQ

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Connecting Differential Voltage Signals to the NI 9207 avoiding use 1M resistor for each channel.

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

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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 ...)


Greetings from Germany

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

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