Split signals

[Nick5405]

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

[dbell0971]

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

[Nick5405]

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

[dbell0971]

No problem, wish we could've found that sooner.  Hope it runs smoothly from here.