problem with gpib fiber extenders with multiple devies on the gpib bus

[just_looking]

am using black box gpib fiber extenders. have multiple devices on the gpib bus. its dropping odd packets.
we are thinking the problem is multiple devices on the gpib bus. we have increased the timeout but that has not fixed the problem. at this time the setup in the lab is a NI sbus GPIB card in a SUN 4500 connected to the gpib fiber extenders, then the gpib devies. the fiber cables are about 60 feet long. we are using our own C++ code. we are thinking about trying NI gpib fiber extenders, but perhaps the problem is somehting else, not the type of fiber extenders.

[theW]

Hi,

Are you able to tell that the extenders are dropping packets because you have a GPIB Analyzer board on both sides and do not get consistent data? That is the only way I know of to be absolutely sure that packets are being dropped. Fiber extenders mainly add an extra delay between when a command is issued and when it reaches the instrument. Some fiber extenders may not support certain GPIB functions like Parallel Polling. Which packets are being dropped?

Have you moved the instruments to a location where they are not being run across the extender and had success with your program? This would allow you to eliminate the extenders as the problem.

If it does turn out to be the fiber extender, I would check with the manufacturer support to see if they have
any information about this sort of behavior.

Hope this helps.

Scott