Agilent 34460A VISA problem

[Atizss]

Dear users,

I have encountered a problem with my Agilent 34460A multimeter. Here is the background:
I am using the driver provided from NI website.

 LabView version is 8.6

NI VISA version is 5.4.1


Usually I can initialize the equipment and work with it, calling "Close.vi" provided in the library at the end. However, if I stop the program midway, it is extremely difficult to start it again without errors. Currently I have no idea when it works. If I stop it midway and then run it again, it either throws error on Visa Clear :

and this particular error is documented as The value of some parameter (which parameter is not known) is invalid. This I find not very helpful. The weird thing is that I can still communicate with the device from MAX panel:


which makes me wonder, why LabView throws error? My guess is that since I do not close VISA connection, it still might be open, or, my second guess was that I leave the tool in unknown state, which it might not like.
Exploring the first option, I tried restarting the computer and tool. This did not help. 
Exploring the second option, I reset the multimeter to factory settings using front panel. Again, no success.
Reading up on forum, I noticed some people mention that disallowing the PC to turn off USB hub to save power might help, but it did not.

Then at some miraculous moment it starts working again.

I really do not know how to proceed, and how to solve this problem.

Any ideas?

Edit: I noticed that even when the initialization succeeds, the program hangs in middle of error query:

It looks like it is stuck on Visa Read, and I cannot stop the VI, I have to unplug the tool. If I disable reset, it hangs even before on Visa Clear.

[NIRebecca]

Hi Atizss, 

How are you stopping the program? If you're pressing the "abort" at the top of LabVIEW (highlighted below) that might be causing your issue. This isn't a stop button, and it doesn't give the program a chance to finish and close off references to the device. 

If you'd like to have the option to stop your code I'd put a programmatic stop button in that closes the while loop and lets the Close.vi run.

If I've misunderstood the code let me know! 

Rebecca

[nicolmarco]

Hello,

Did you get a solution to this issue? Because I also face similar problem. I am using latest 34461A drivers and LabVIEW hang with initialize itself.

I can not even abort the VI.

Pls advise.

Thanks,

pooja

[NIRebecca]

Hi Pooja,

It might be worth opening a new forum for this new issue, and including your code in the post.

A few quick thoughts:

If you restart the PC and run the code does it hang the first time you abort? If not I'd say this is still a symptom of overusing the abort button and not killing off open references. 

Check the CPU/memory of your computer to ensure this isn't causing LabVIEW to be unresponsive. If it's high make sure any loops in your code have some kind of timing included. 

Sidenote: <Ctrl> + <period> keyboard shortcut is sometimes quicker than the abort button.

Thanks,
Rebecca