HP5350B not responding to GPIB commands

[vivek.madhavan.13]

Hello,

I have been using the HP5350B, an old HP frequency counter for a remote control application. I am using the GPIB commands to send and receive messages from the instrument. I have attached the screen shot of the code which uses a GPIB read block to read the value from the instrument. Earlier when I used a GPIB-USB-HS connector I was able to get the desired values using this code. Recently I got a PCI-GPIB card which I installed in my computer and ever since have been trying to read measages from the instrument with this card in the computer, but I have not had success at reading the value from the instrument using the same code. I have been getting the error shown in the attachement. The only difference I found between using the GPIB-USB-HS and PCI-GPIB card is the change in the address of the instrument from GPIB1::7::INSTR(for PCI-GPIB card) to GPIB0::7::INSTR (GPIB-USB-HS) which showed up in NI MAX.

Now when I connect the GPIB-USB-HS back to the computer and try communicating with the device with the same code I am unable to reproduce the results I was getting earlier. I would really appreciate any comments in helping me resolve this issue.

Thank You,

Vivek

[JÞB · Accepted solution]

Straight from the LabVIEW Help file

When there are multiple GPIB controllers that LabVIEW can use, a prefix to address string in the form ID:address (or ID: if no address is necessary) determines the controller that a specific function uses. For example, to set GPIB controller 2 to talk to a device on address 3, use the prefix 2:3. If a controller ID is not present, the function defaults to controller (or bus) number 0.

You have changed your hardware configuration such that "7" is no longer unambigeous.  use "0:7" or "1:7"

[vivek.madhavan.13]

Thank you Jeff for your support. It was very helpful.

Thanks again,

Vivek