VISA GPIB & LabVIEW versions

[Intaris]

I recently spent a day trying to get a VISA function to work for an old GPIB Instrument.

I was able to use the VISA Interactive control (A very old version - from 7.1 days) to work even though it apparently completely refused to append a TermChar when writing but it worked.

Using the SAME function from within a compiled LV 2011 program could not communicate at all.  In fact trying to get the LV 2011 program to run would completely block and further communication to the instrument even via the interactive control.

I was unable to install a newer version of VISA because the user had LV 7.1 installed and later VISA versions are not compatible with LV 7.1.

I eventually got the program running using the lower-level GPIB functions.

What are the issues with LV version compatibility in this regard?

Shane

[crossrulz]

Was the 2011 program running on the same machine as the 7.1 program?  I ask because I have had older instruments for some reason will only talk with older GPIB cards.  I think we eventually found an additional wait was needed somewhere in the low level code to get the newer cards to work.

[Intaris]

Yeah, running on the same machine.

I had initially thought things would work because a VISA search showed up all the GPIB instruments but try as I might I couldn't get ANY response from the instrument at all.  The VISA Interactive control (On the same PC as the LV Version and my compiled 2011 program) worked.

It therefore can't be the controller card.

I have another question:  The graphic shown HERE for LV Version compatibility with VISA....  Does it refer to the compatibility with the LabVIEW IDE or also compiled versions of software?

Shane.

[Intaris]

Can anyone comment on the run-time compatibility of different VISA versions?

The problem I have mentioned above is explainable for me only if the compatibility of VISA versions is not limited to the IDE but also the run-time version.

My observation has been that VISA (4.0x) was working fine on the test machine (Using the VISA Interactive Control panel) but collapsed completely as soon as I tried to make a VISA call from a LV 2011 compiled program.  It seemed that the LV2011 program was deadlocking or otherwise completely blocking the driver.

Some official insight on the matter would be appreciated.

Shane

[Intaris]

Nobody going to waste a few minutes on this?

Something I've thought of : Would accessing the port via network (VISA shared port) help compatibility?  I'm assuming the abstraction through TCP/IP might help alleviate some problems observed by calling System DLLs directly from LV 2011........

Shane