Error initializing DMM with OpenDev

[BlueBirdHouse]

When initializing a Keithley 2000 DMM through GPIB using the OpenDev command it returns an invalid number.  Checking the NI instrument explorer and querying the DMM shows an active connection.  Failing code below.

    /*  Initialize the GPIB interface.  */
    if (bd[instrID] <= 0)  {
        if (instr_cnt <= 1)
            CloseInstrDevs ("kei2001");
        bd[instrID] = OpenDev ("kei2001", "kei2001");
        if (bd[instrID] <= 0)  {
            kei2001_err = 220;
            return kei2001_err;
        }
    }

[Matt_S.]

Hi BlueBirdHouse,

I wanted to get a little more information from you on this.

What version of NI-VISA are you using?
What version of NI-488.2 do you have installed?
Can you see this device in MAX? Can you query this device within MAX?
What operating system are you working with?

Regards,
Matt S.

[BlueBirdHouse]

Matt_S,

Thanks for your reply, I'm currently running:

NI-VISA v1.1.04

NI-488.2 v3.0

MAX sees and successfully queries the DMM

OS Win XP

Let me know if there's anything else you want to know.

[Matt_S.]

Hmm, we may be having some versioning issues.

A) Uninstall 488.2 and NI-VISA
B) Install NI-VISA v. 3.3.1  from

http://digital.ni.com/softlib.nsf/websearch/CC5A993FEFA83D498625704600677AE7?opendocument&node=132070_US

C) Install 488.2 v 2.4 from

http://digital.ni.com/softlib.nsf/websearch/1DDE5C48F30C2C658625702000681295?opendocument&node=132060_US

I'm not sure why you would be seeing 4882. v3.0, version 2.4 is the latest version out.

Once you get these installed, we'll at least be sure that we're not having problems caused by old driver versions.

-Matt S.

[BlueBirdHouse]

I'm sorry, I was mistaken.  488.2 is v2.2 and VISA is v3.1

I have a simular system with identical drivers that is currently working, but I'll install the new drivers on the non-functioning one if you still think it might help.

[BlueBirdHouse]

The problem has been solved, the file C:\Windows\system32\GPIB.ini had the device names set to default (DEV1, DEV2, etc.) instead of "kei2001" as specified in my code.  Correcting that solved the communications problem.

As a note to NI, I think the problem would have been easier to solve if I could have looked at the code for the OpenDev function, so making that code available or more easily accessible would be nice.

[barry66]

Thanks Bluebird, I was also getting errors with OpenDev.

As a further note to NI I think it would be helpful if a search of the LabWindows and 488.2 help for GPIB.ini actually found something. None of the documentation for OpenDev mentions that it is dependent on the GPIB.ini file.