problems with GPIB devices

[Gerd W.]

When running my program to control a measurement, everything works fine.
The program can communicate with all the GPIB devices. When I start
the program again (without rebooting Win2K), from time to time it
refuses to communicate with the GPIB units. Now I found out it helps
to start MAX2.2 (Measurement & Automation Explorer) and to scan the GPIB
bus. MAX identifies all devices without problems and my LabVIEW program
also runs fine now...
So why do I have to call MAX to have my LabVIEW program have a communication
via GPIB?

[Dennis_Knutson]

I'm pretty sure that before MAX starts the scan, it initializes the card/bus. Is it possible that your program might sometimes leave an instrument hung up because an operation is still pending? Are you using VISA or GPIB functions?

[Irene He]

gerd.wieczorek@epost.de (Gerd W.) wrote in message news:<76b760f5.0302250610.7a19cf83@posting.google.com>...
> When running my program to control a measurement, everything works fine.
> The program can communicate with all the GPIB devices. When I start
> the program again (without rebooting Win2K), from time to time it
> refuses to communicate with the GPIB units. Now I found out it helps
> to start MAX2.2 (Measurement & Automation Explorer) and to scan the GPIB
> bus. MAX identifies all devices without problems and my LabVIEW program
> also runs fine now...
> So why do I have to call MAX to have my LabVIEW program have a communication
> via GPIB?

Do you use VISA or regular GPIB functions? If use VISA, you may have
to close it properly when your software exit, oth
erwise the resources
may be locked up. And by using MAX somehow the resources is freed by
it after it's operation.
Irene
www.geocities.com/irene_he

[GerdW]

Well, I'm using standard GPIB functions. Therefore
I don't have to close any handles...

Best regards