too many GPIB instruments found while using one

[Adam77]

Hello,

I was using a NI 488.2 GPIB card to communicate with a keithely 487 picoammeter for couple of days sucessfully. Out of sudden, there is a problem with communication and I cannot run the identical code that I used before. The communication is going on but erroneously. For example, if I run the NI sample code "FindInstruments.c", instead of the one instrument with PAD 22 (as it found before) it finds 9 instruments with PAD 22-30 (the code searches till 30).

First I thought that the Keithely broke down after so many trials with my code but we have an independent computer with a GPIB card and there the Keithley with the same cable runs as before, without problem. Is it possible that the GPIB card broke down? I didn't touch it meanwhile, it sits in the same computer from the very beginnign of use. I use win XP. It is not excluded that Win XP did some updates meanwhile. Is it worthwile to install the card in another computer?

thanks for help, Adam

[cristitranca]

Hi Adam.

My suggestion will be to try to install the card on another computer to rule out the card and operating system from the causes. 

Please tell me if the on another computer you can correctly detect you GPIB device.

Regards, 

Cristi

[Adam77]

Dear Cristi,

I have just installed the card on a win 7  and the issue is just the same,

Adam

[cristitranca]

Dear Adam,

I would suggest to install the newest drivers that you can find on ni.com/drivers   . For gpib the drivers are NI-488.2  3.0.2(version from 03.2012).

Although yor software detectes multiple devices, can you work with you GPIB instrument that is connected to the GPIB card?

What happened before the issue appeared? Did you made any driver upgrade?

[Adam77]

Dear Cristi,

I have installed the new driver 3.0.2 and it works again! Now only one device at address 22 is detected and all other programs work fine. No idea, what happened. However I'm happy that it works!

Just to reply your question: no I was not able to work properly with multiple devices detected. There was a communication with the device but in a kind of erroneous way. Some commands were O.K. but some leaded to unexpected charracters on the display of the device that I didn't even find in the documentation.

thanks for your help,

Adam

[cristitranca]

I am happy to hear that the problem is solved.

Thank you for aswering my question also.

Regards, 

Cristi

[Adam77]

anyway I'm a kind of curious why this happened, just to prevent similar troubles in future. The only reason I can find now is that some updates of windows were not compatible with the 2.7 version of the GPIB driver that I had there previously. Is this possible? Do you have any other experiences with these incompatibilities?

Adam