NI 9205 input configuration possibilities

[toddy]

I was wondering if anybody knows whether the inputs on the NI 9205 module should work, given the way I've set them up...

It is a 32 Channel (Single Ended) or 16 Channel (Differential) module, but I wonder how flexible it is. I'm using it in a NI 9148 chassis using the scan engine, and I have configured it thus:

Channels 0 - 3 Single ended

Channels 4 - 7 Differential

Channels 17 - 23 Differential

I'm getting some strange numbers back from channels 4-7, and I wonder if it's not quite as flexible as I had imagined. Does anybody know if what I'm doing here should work?

I could change channels 0-3 to be differential, but I was hoping to avoid it, as this is part of a live system.

Thanks in advance!

[testproggie · Accepted solution]

The NI 9205 should be very capable of doing this as I routinely do "mixed" mode inputs with them. Is it possible to show the portion of the block diagram that is configuring the DAQ?

There is 1 consideration in that common mode voltage cannot be exceeded otherwise readings will be in error.

[toddy]

Thanks for your reply - it seems that linking the -ve side of the inputs to common was the answer - a simple grounding issue in the end!