If you are just getting started with IEEE communication in MET/CAL, follow the steps outlined here: Troubleshooting GPIB Communications
If you are having intermittent timeouts here are some things to try:
1. There is a bus timing setting in NIMAX that affects how well instruments communicate over the bus.
By default, the bus timing setting is set to 500nsec:
This is just not quite enough time for some instruments. Changing this setting to
Setting 2 (2user) will help fix many timeout issues.
2) Address conflicts can cause problems. Double check the addresses of your attached instruments and make sure all of the addresses are unique.
3) Problems can be caused by worn and damaged cables. Simply changing out a cable is the best way to troubleshoot these problems.
4) If you are using a Star configuration for multiple instruments, try changing to a linear connection type (or from a linear to a star) which will force to you verify that your connectors are tight:
5) Occasionally you may have errors because you either have too many instruments connected or exceed the max cable length. These limitations are documented in the IEEE/IEC standard IEC-60488-1.
If you are still getting IEEE communication errors you can turn on GPIB Trace using the instructions here: