Instrument will hang on *idn? but no other commands

[FLAnatic]

In my program if I do a VISA write of *idn? to my instrument and then take a VISA read it will work. But then my instrument will hang and not respond to any more writes or reads. If I make it a sequence and Write *idn?, wait 10 msec , then read everything works fine. But the instrument does not hang on any other commands that I write and read. *idn? is the only command where i have to put the delay in to keep the instrument working properly. Any ideas?

[Gorka Larrea]

Perhaps you'll get with that timing cos it seems to be necesary for the instrument, else, posibly, it has no time to retrieve the answer, and visa read will pass an error, avoiding any other visa to work. In my opinion, you should use the wait, as long as it's not too much.
Good luck

[FLAnatic]

I was just wondering why I need the delay for the "*idn?" command only? When I write and read with any other commands I dont need the delay.

[Gorka Larrea]

No idea on that, but i'm gonna make a shot. Are you using VISA read and write in series? I mean, the refnum from write passes to read, and so does the error cluster? If not, try to do it this way so that all goes one after the other, and not all at once. There can be something with timing too, perhaps you should take a look to the timeout property.
Good luck

[Rob Cole]

This sounds instrument related. But still strange that it only happens with the one command. Can you get a different instrument and try the same identification sequence? This should tell you if the problem is in the instrument or something with your GPIB card.

Rob