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Why I got an error when I continually change channel connection on PXI2530

I use 2530 as a 4x32 matrix. It works well when I use initilize vi -> make channel connect vi and close vi . But when I put make channel connect vi into a loop and change the channel in every loop, it output " the session is not valid " error. the channels are not duplicate in every loop, they can connect well in Switch Front Panel. So what's wrong? need I disconnect before  make new connection?
Message 1 of 4

If I understand your application correctly, you are opening and closing niSwitch session for every connect you want to make. Please try to limit opening and closing of a session to once per application. Doing so will save you significant amount of time as the initialization is not an inexpensive operation time-wise.

Another benefit from using a single session is that errors like the one you've got (invalid session) should be rare and far apart.


If what you're doing is a single open/close session, and you only loop on switch connects, then yes, you will have to perform a disconnect operation before trying to make the new connection between the same two channels.*



 Hope this helps!


best regards, 




* this of course depends on the topology. In general, matrices will allow more than one connection to a row or a column (but still the endpoints must not be the same), while muxes will not. There are no implicit disconnects in a switch session.

Message Edited by Srđan Zirojević on 09-28-2009 08:23 AM
Message Edited by Srđan Zirojević on 09-28-2009 08:24 AM
Message 2 of 4
yes, I only open and close the session once  in application, the error occur in second loop. my vi is basicly same with example, I just put the connect vi into a loop, but it can't work well, it's very strange, I will check other parts of my application, maybe the error is from other part of my vi.  thank you very much. 
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Message 3 of 4
Can you post a small code snippet or picture of your code?  Perhaps this is one of those things that's easier to debug if we can see how your code is running.
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Message 4 of 4