Unknown code error in Python using NI GPIB-USB-HS

[svc]

Hi, 

I am using NI GPIB-USB-HS device to control Keithley 2700, Chroma load and Agilent DC power supply. I have all the devices connected and I can see it as the GPIB devices in Python.

But when I tried this self identification command, I get an error saying,

This happens to any command that I try to run. I have the drivers installed. I am not sure where I am going wrong.

Is there any setup that should be done before running these commands? Any suggestions would help. 

Thank you!

[cstorey]

Looks like you have pyVISA configured correctly, but just in case read - https://pyvisa.readthedocs.io/en/1.8/faq.html#faq

Which device is at address 3? Keithley 2700 and the Agilent DC supply (if it's newish) should reply to "*IDN?"  Not sure about the Chroma.

Are you sending termination characters or how are they being handles?  I think at the least that needs a "\r", o r"\r\n" but it depends on the instrument settings.

Its been awhile since I used pyVISA, but I think termination or timeout is the problem here.  Look here for details - https://pyvisa.readthedocs.io/en/1.8/resources.html

Craig