I need to close all visa session after sending SYSRESET to avoid NRFD or NDAC (ENOL) error messages, why?

[Olivier B.]

I send a SYSRESET to a GPIB-VXI/C. Then, when i try to communicate (visa read message) with other instrument in the VXI, i get the -1073807265 error (NRFD & NDAC -> no listners).
To resume communication with instruments, i need to close all visa sessions.

My program runs under LabVIEW 6.1 (usually no need to open/close visa sessions). However, i observed same behaviour of my system when i open visa sessions (one per instrument and one for the controller) under MeAsurementeXplorer and send the SYSRESET command.

I found the following note in the knowledgebase reporting the same kind of problem, but not solving my problem:

After sending the SYSRESET command to
a GPIB-VXI/C, all subsequent commands return ENOL (No listeners found).

Hardware: VXI/VME/MXI>>VXI Interfaces>>GPIB-VXI/C



Problem: After sending the SYSRESET command to a GPIB-VXI/C, all subsequent commands return ENOL. This is happening because the GPIB-VXI/C needs some time to rerun RESMAN after the VXI reset. Wait until the sysfail light goes off and then a few more moments (after the sysfail goes off, there is some time needed for RESMAN to run) and then try a GPIB command (e.g. ibwrt "*IDN?") to the GPIB-VXI/C.

Solution:

Also, check for the GPIB-VXI/C configuration. It might be possible that the wait period (wait for sysfail to be removed from a vxi backplane) is larger than normal values (5 sec...)

Related Links:

Attachments:




Report Date: 25/11/1996
Last Updated: 11/08/1997
Document ID: 0ROGKM2Q

[JedRetherford]

Olivier,

This is the expected behavior of the GPIB-VXI/C and is something that you will want to incorporate into your programming. In conjunction with your SYSRESET call you will also need to close and then reopen your VISA sessions.

If you plan for this behavior in your programming it should not present much of a problem for your application.

Regards,
Jed R.
Applications Engineer
National Instruments