Low Level GPIB Communication with 2611B

I have a 2611B connected via a Keysight Technologies 82357B USB to GPIB adapter.

I'd like to communicate with the 2611B using low level GPIB commands, possibly without some other additional layer.
I have a small routine that just sends the command over GPIB and receives a string, but I first tried to use the Keysight Interactive IO tool.

If I send

*IDN?

I receive

Keithley Instruments Inc., Model 2611B, 4038432, 3.0.3

so the connection itself should work.

But even simple commands like

:SYSTem:LFRequency?

just result in a timeout.

 ! VI_ERROR_TMO: A timeout occurred
Visa ErrorCode: 0xBFFF0015 (-1073807339)

Can somebody tell me how to make the 2611B respond to my requests?

Thanks!
 

Since your *IDN? query is working well, I'd say your communication is proved.

You are getting a timeout on the other query because it is not a valid command for the 2611B.
Therefore, that command will not cause any response message and your gpib read times out.

I suggest you consider updating the firmware level.  You are at 3.0.3.  Version 3.4.2 is available for your unit.
You need a login to the tek.com site, but otherwise is a free download.

Also while there, download the reference manual which details the commands that the 2611B does understand.
The user manual offers a subset of that info and some typical use case scenarios.

If you want to know the line frequency you can write a command:  print(localnode.linefreq).
Then read the response that is "printed" to the output queue.

Downloads for the 2611B