07-28-1999 10:25 AM
06-14-2007 06:40 AM
Hi all,
Is the above still true? i.e. VISA locking does not work with serial devices, or is this just an old problem? It's just I have tried using it with no success.
-Martin
06-14-2007 08:07 AM
Locking is a function of the transport layer (i.e. GPIB)
Serial originated with interfaces to teletypes where we used reed relays to create the binary stream. There was never any thought given to locking when it was first implemented (he#$ we were happy it worked).
I have used an Action Engine to implement locking for multiple devices. Just make sure the transmit recieve operation for each device are contained in the same action so that the reply from one device does not get read by the other device.
Ben
06-14-2007 08:31 AM
Thanks Ben,
Just wish NI would state things like this in the VI context help. I have re-written using semaphores. Thanks for the link to the "Action engine" also.
-Martin