Hello,
I have a VI which needs to send several VISA commands over a GPIB interface to configure instruments, which has been running fine for more than a month. Recently however, it has slowed down to a crawl. It used to take less than half a second to run, and now takes almost 8 seconds.
I have isolated the problem to the "VISA Write" subroutine. When I send a command to the instrument manually using the VISA Interactive Control utility, it happens almost instantly (less time than it takes me to take my finger off the mouse after clicking "Write"). When I send the same command to the same instrument by calling the "VISA Write" subroutine, it takes about 1100ms to return. I have joined the VI code I am using to benchmark execution time.
What do you suggest I do to solve this problem? I have tried rebooting the computer, deleting and re-adding the instruments in NI-MAX...
I am using LabVIEW 2010 and NI-VISA 5.4 on Windows XP Pro SP3.
Regards,
Louis H.