Hello whoami,
Can you provide some additional information about your application? What is your hardware (PCI/ISA cards etc.)?
Here is some additional information about Asynchronous/Synchronous GPIB Reading and Writing in LabVIEW:
http://digital.ni.com/public.nsf/websearch/DCED43E05D7074808525637E00731397?OpenDocument
http://digital.ni.com/public.nsf/websearch/019D9865AF0FAF2186256C770079ED5F?OpenDocument
Thank you for choosing National Instruments!
Swapnil P.
National Instruments Engineer