The VI VISA:Write does sometimes not finish execution! What can be the reason for this?

[robert_p1]

Hi everybody, I already posted this question in the Hardware Boards, but maybe this was not the correct forum as I do not get any replies. So I'm now trying to post this in the general LabView Forum as I am quite desperate to find a solution for my problem!

I truly hope someone can give me a hint how to solve this ...

I have got a problem with the VISA:Write VI in LabView 2009 SP1 32bit (WinXP). When using it to communicate with a serial RS232 device the VI sometimes does not finish execution. Sometimes this happens after 2 or 3 consecutive calls, sometimes only after some thousand calls. When using the "Highlight-Function" one can see that the VI gets called correctly but it will NEVER finish, issue any kind of error message and of course also not hand any output-arguments to the subsequent VIs what causes the whole application to freeze. The Win Task-Manger shows no increased CPU-Load while "permanently executing" VISA:Write. The only possiblitiy to stop the execution is to push the "Close Button" of the Top-Level VI Window. The "Stop Execution" Button will be ignored. When forcing the application to quit, LabView shows a small message window that it is "Resetting" the Top-Level VI. This will also never finish. LabView can only be stopped by using the Win Task-Manger.

As this happens when using the Built-In COM Ports as well as when using those provided by a PCI Port Extension Card I am quite sure that it is no IRQ or Memory collision problem.

Can anybody give me a hint what is causing this problem and how I can find a workaround?

Thanks in advance and best regards,

Robert

[Christian Mergl]

Duplicated post, please continue on this thread:

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/The-VI-VISA-Write-does-sometimes-not-finish-e...

Thanks,

Christian

[robert_p1]

Dear Christian,

as you can see from the first sentence of this post I'm fully aware that this is a duplicate thread, and I know it's "bad habit" but as you can see, I did this for reason. Anyway ... thanks for pointing out my wrongdoing!

Do you also have a hint for solving my problem?

Robert

[smercurio_fc]

Christian has already responded to your question in your original thread. Please keep the discussion in that thread so all pertinent information is in one place. Thanks.