MAX and Async Read/Write

[ray_martin]

Didn't MAX use to have an option to perform async read and write in the "Communicate with Instrument" window? I'm presently using Measurement & Automation Explorer 5.4.0f0. Please explain how I can use MAX to start and terminate async read and write calls.

[JÞB]

I would expect that you would want a syschronous tranfer with the VISAIC utility.  Asynch calls for a single device user interface just make very little sense to me.  Even if you are using a VISA Class that supports the IO completion event (not true of VISAIC opening a com port)

Dod you enable the IO Completion event?  Without some hardware on this machine I can't really see if that would enable asynch options

[ray_martin]

VISAIC did use to support Async. See figures 7 and 8 on this link. It appears this was silently removed in later versions. When doing a Read or Write with Async checked, I believe it then showed a terminate button while it was executing. The benefit was this let you cancel the operation rather than waiting for a timeout error. Plus it was a quick sanity check of the instruments ability to perform and terminate async I/O.

NI does have a good async read/write Measurement Studio VB.NET sample project called SimpleAsynchronousReadWrite.