why do 'cmpl' and 'end' indicators stay illuminated on the IBSTA window when I send a command from a GPIB/ENET-100 to a AT-GPIB/TNT card ?

[kwolsen]

I have a system that contains a GPIB/ENET 100 card that communicates to another system that contains AT-BPIB/TNT card. I send the AT card commands, most of the time it seems them correctly in the IBSTA window, but sometimes I send a command and it doesn't see the command, but the CMPL and END indicators illuminate and stay illuminated. Then, when I send another command, the prior command that caused the CMPL and END indicators to illuminate is shown to be received in the IBSTA window. Then each sucessive message is shown in the window, but skewed by one. Any ideas of what is wrong ?

[ndiamond]

I am not sure what you mean by your IBSTA window, but the behavior that you describe is familiar. When I was doing some GPIB programming for a customer, I thought that this was just one more effect of my not yet knowing quite how to program it right. But I did get it working, so here are two guesses as to what you might need.

Do you have the latest drivers?

When you know about the CMPL indicator, you see it displayed somewhere, but does your program also know about the CMPL indicator? If your program hasn't resynchronized with the driver, then the driver has to assume that the program still considers the operation as being in progress, and maybe it can't discard buffered data.

[theW]

I'm also curious what you mean by the IBSTA window. Are you running an NI-Spy capture while you're doing all this? On what computer do you have the IBSTA window? Do you possibly have a GPIB Analyzer board?

Scott B.
National Instruments
Applications Engineering