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08-07-2012 12:08 PM
I am using a cDAQ9188 with a 9205 32ch analog in module.
I am looking at 2 groups of 3 signals
I can split the signals but 1 of the 6 always appears to be a duplicate so although I get 6 measurements
on the screen one of them is missing and a duplicate of another is there.
I was using Ai0/2/4 for 1 group and Ai1/3/5 for the other.
It appeared that Ai0 and Ai1 were dupes so I moved the wire to Ai6 from Ai1 and I still end up with a dupe
just a different channel.
I have tried expanding the Split signal from the top and the bottom and looked over all the split signal posts
but I don't see anything like what I have.
Any help appreciated
Thanks
08-08-2012 07:13 PM
Hi Nick,
What kinds of signals are you measuring? Do you have the device configured in differential mode or in single-ended mode? Are all of the channels measuring the same kind of signal? Can you test your signal with a DMM to see if the signals coming into the DAQ device are what you expect them to be?
Thanks,
David B
National Instruments
08-08-2012 07:35 PM
Hi David and thanks for the reply,
There are 3 signals (X2) one is about -5 to +5 volts, the second is about -8 to +8Volts and the 3rd is a 0 to +8Volts square wave.
After a lot of switching the wires around I figured that when I got a bad contact on a wire to a channel it does pick up noise from others
so much so that it looks just like a duplicate, I think that's what the problem is not the switch function.
I have to work on it some more to be 100%.
I think that the answer will be to solder a solid wire or pin onto the cable and use the pin to connect up to the module instead of the trimmed
bare wire.
Too bad I didn't do this a couple of days ago, I kind of read something about it but I expected some X-talk, in my mind that's like a
watered down signal similar to another channel not something that looked identical to another channel.
I'll post again if the pins are the answer
Thanks again
08-09-2012 06:12 PM
No problem, wish we could've found that sooner. Hope it runs smoothly from here.