LabVIEW does not release GPIB bus.

[SparkyOne]

I have a really odd problem, that I'm experiencing with a development program.

We have an old 8510C VNA that we wrote a new test routine to automate some monotonous testing sequences.   In the past, once we would stop the VI, the bus would be released so that the user can manually control the device.

However, for some reason....the Bus is not being released, until LabVIEW is completely shut-down on the Test Controller.   This means that even if the VI is not executing, the front panel controls on the 8510C are completely locked-out....even PRESET does not release the device.    So if the Test Tech wants to manually troubleshoot, they cannot.

I found a help webpage, but even these steps did not clear the issue....unless I'm missing a open connection somewhere.   Not sure what that would be....or how to find it.   I only have this single device on the bus, so once it is closed, the Bus should release as well.

http://digital.ni.com/public.nsf/allkb/22CC355D0CBD355D8625753E0050E4F2           How Do I Close a GPIB Reference When My VI Stops Executing?

The this problem is being exhibited on both a NI PCI GPIB card, and a GPIB-USB-HS, and I'm not sure where to start troubleshooting?   Any guidance would be appreciated.  Thanks,

[Gregory]

If you make your application into an executable, does the problem go away?

[billko]

Has the address of the VNA changed?

[billko]

I think this is a candidate for conversion to using VISA to communicate with the VNA.  It's a lot simpler to use, and is bus-agnostic.

[cstorey]

This isn't just the VNA being left in "REMOTE" mode after the program has finished?  Older instruments like the 8510C force you to press a "Local" button to take front panel control again after communicating over GPIB.  See page 170 - http://literature.cdn.keysight.com/litweb/pdf/08510-90281.pdf

Aside from that it could be that there's a badly formed command at the end of the program, and the instrument is waiting to send/recieve more data before proceeding.  

Posting your code would help debug that.

[SparkyOne]

No, the address of the VNA is, and always has been 16.

makes no difference as an EXE.   Problem exists both ways.

i'm confused about the VISA statement?   I was under the impression that The plug-n-play drivers used that?   Uses VISA to open & close the GPIB connection.....unless I'm just that clueless...which is a distinct possibility.

[SparkyOne]

I'm sorry, I will upload a code snippet tomorrow.   I'm really under the gun tonight on time....

[SparkyOne]

It may be that the device is still in REMOTE.   The indicator is lit on the front panel, bill I do not understand why. 

We use the CLOSE function out of the LabVIEW driver package.   Is there another one that needs to be added to switch back out of REMOTE?  

[billko]

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@SparkyOne wrote:

No, the address of the VNA is, and always has been 16.

makes no difference as an EXE.   Problem exists both ways.

i'm confused about the VISA statement?   I was under the impression that The plug-n-play drivers used that?   Uses VISA to open & close the GPIB connection.....unless I'm just that clueless...which is a distinct possibility.

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Yes, the plug n play drivers use this... but the plug n play drivers are just drivers that you would make, but are gift-wrapped in a standardized interface for ease of use.  🙂

Download them and you can get some good ideas on how to implement your own drivers, or maybe they are good enough to use directly!

[Blokk]

I am not sure if this helps you, but if you are talking about the Agilent 8510c unit, I would try the following VI, see below. I just downloaded the LabVIEW driver from NI.com, I have no idea if this works, since I do not own such hardware to test...

..\Agilent 8510C\Public\Configure\Service Functions.vi