PXI-2569 100Ch SPST - Switching one channel causes a pulse in others...?

[joedowdle]

Hi everyone,

I wrote some LabVIEW code that runs a PXI-2569 through VeriStand (i.e., it's a custom device) and for some reason when I switch on one of the switches it temporarly pulses several channels one time when switching.  This switching module is being used for several switch to battery and switch to ground switches.  So for example, when I switch on channel 1 it temporary pulses channels 1-14. Same for channels 15-28.  I didn't check all 100, but the pattern seems to be grouped in groups of 14 channels (not sure if that's siginificant at all).

Now obviously this isn't a good problem to have.  I have been told by a co-worker that this has been an issue in the past with some of the NI switching modules, but I don't know how to fix it.  I have included the main portion of the code that runs the switching and hopefully that will help identify the problem.

Any help would be appreciated.  Thanks.

[J-Barticus]

Hi joedwodle,

Have you tried using test panels or examples shipped with LabVIEW to see if you receive the same results? Do you have another 2569 you can test the code with, do you receive the same results? I am trying to discern if there is a problem with the hardware or possibly an error within your code so we can better troubleshoot the issue.

-Jake B.

[billko]

Hmmm, I remember something about the impedance of something?  Does this jog anyone's memory?

[joedowdle]

Thanks for the input but I actually found the problem to be within my code.  For some reason there was a repetative operation happening and for some reason this would cause a bunch of channels to switch for one loop and then switch back.  I couldn't figure out why it was happening, but I was able to fix it.

Thanks again.

[SolaireOfAstora]

Hey joedowdle,

I'm working on a similar switching custom device, what exactly was causing the repetative operation?

Thanks,

Solaire

[joedowdle]

The problem ended up being that I had a redundent for loop in my program that causes sections of switches to turn off and then on when you switched a switch in that "group."  I wasn't able to figure out exactly how or why it was just parts of the switches and not all though.  Basically I just removed the loop everything worked out just fine.  I don't know how much that would help you since it was just a programming mistake on my part, but if I can help in any way let me know.