GPIB - VISA issues with Agilent 4155B analyzer

[Aurelito]

Hi everyone

I am having trouble with GPIB communications to a HP 4155B analyzer.

- My GPIB card (NI PCI-GPIB) setup is OK, I can communicate with other instruments (both in MAX and Labview)

- I have updated to the latest 488.2 and VISA drivers

- The analyzer appears in MAX and seems properly recognized

- When I start a communication with the analyzer in MAX, I can use a few queries (*IDN? and :SYST:ERR? for instance) which work fine. On the other hand when I write most other commands / queries listed in the documentation (such as ERR? or LOP?) they are not accepted and cause an ERR -113 Undefined header. I have tried several termination settings in MAX (send EOI / terminate read), no luck.

- I also tried to use the National Instruments drivers hp415xa directly in Labview but Initialize.Vi fails. First I had an error with the "Old visa open" box , which I updated to a "Visa open" box, which now receives the GPIB ID of the anlayzer (GPIB0::7::INSTR) as a constant. I still get an error from "Visa open" with code -1073807343 , although the analyzer has GPIB address 7.

Any clues ?

[Dennis_Knutson]

When you replaced the Old VISA Open with the VISA Open, did you wire up the front panel VISA session control to the connector pane? You should have deleted the 'instrument descriptor' string control. This would have left the upper left terminal of the connector pane unconnected. Wire the VISA session here.

As far as the commands that generate the error, you might want to double check the manual for the proper prefix. I know the ERR? command is preceded by :SYST: in the driver. The errors are not due to any setting of the GPIB board or VISA problems.

[Aurelito]

Yes, I got rid of the instrument descriptor, and wired the VIsa Session control to the upper left connertor of Visa open - doesnt work. I also tried replacing the Visa Session control by a Visa Session constant (containing the correct GPIB ID) , same error.

As regards commands : both :SYST:ERR? and ERR? are listed in the doc, the first work but the second doesnt...

Thanks for any suggestion

[Dennis_Knutson]

I'm not sure what else could be the problem with the driver. You did select the instrument by clicking on the little arrow on the right side of the VISA Resource Name control didn't you? If the instrument is listed there, that means that it was found by MAX. Do you get the error when you just run the intialize function?

In regards to the commands that don't work, are the SYST:ERR? and ERR? commands described in the manual as doing the same thing? If so, I would just mark it down as a documentation error and use SYST:ERR? You might want to see what Agilent has to say.