How do I stop a flush buffers after a VISA write

[bruss]

In Labview 7.1, how can I stop the VISA write from performing a flush bufferes after each write?

I am communicating with an rs-485 device with a rs-232 converter. The package software that came with the divice works, so I know the wiring is ok. After port sniffing, I see that labview send a flush buffers immediately following the write. Is there a way to disable this?

Thanks,
bruss

[craigherdman]

bruss,

Could you possibly post the sequence of calls that are occuring (the specific Windows calls) and an NI-Spy capture? This will help us all understand exactly what is going on. I suspect that if you want to keep a buffer of written data then you would need to set up a software buffer as the buffers on the UART are going to be flushed upon certain non-preventable events. You can explicitly flush the write buffer but cannot prevent it from being flushed.

Craig H.

[BradK]

Bruss,

I am having the same problem as you are having.  VISA is automatically calling IRP_MJ_FLUSH_BUFFERS following a write.   If you have found a solution please let me know.

Thanks,

Brad

[MissyS]

Hi Brad,

Like Craig H. said, can you post the sequence of calls you make and NI-Spy capture of your communication? We may be able to track down what is happening to cause the buffer flushing. Here is a link to a KnowledgeBase that discusses how to perform a good capture for troubleshooting.

Regards,