ENOL with HP-IB device using GPIB-USB-A

[PBatson]

I am attempting to communicate with a HP3458A multimeter using the GPIB-USB-A interface in Windows 2000. I have successfully controlled this instrument using 488.2 and the AT-GPIB-TNT card under Windows NT, so I believe I know the device address and appropriate message parameters. If I use Interactive control to duplicate the commands that I have used successfully on the previous system, setup proceeds without error, but ibwrt "ID?" returns ENOL.

[Randy Solomonson]

Hello-

It sounds like the instrument is probably okay. There is probably either something wrong with the GPIB-USB-A or the connection to the instrument from the GPIB-USB-A. Here's a few suggestions:
-Be sure the interface is attached tightly to the device. Also, check to see that the screws are tightened.
-Try running the diagnostic test for the card.
-Is the ibwrt command on an existing primary address? The original primary address of the instrument may have changed somehow.

Hope this helps.

Randy Solomonson
Application Engineer
National Instruments

[PBatson]

Thanks for your help. I found that the hex-shaped HP3458a retainer screw sockets would not clear the GPIB-USB-A plastic case. Also, the threads were not deep enough to accomodate the GPIB plug screw length. The result was that the plug seated firmly, but did not make electrical contact. I needed to disassemble the GPIB housing, enlarge the plastic clearence on either side of the plug, and place washers on the GPIB screws so that they were backed off about 0.1 in.