How can I clear the parallel port?

[rainer]

I'm sending image-files to a custom made printing unit via VISA through the parallel port.
Sometimes the unit doesn't accept the file.
Therefore I need to clear the parrallel port completely and send the file again.
(Right now I'm switching off the unit and waiting for the error message from WindowsNT).
How can I clear the parrallel port via LabVIEW?
(VISA clear.vi doesn't work, the data is still on the port).

[rtamblin]

I have a couple of suggestions for you, but these may not work if your instrument is not allowing for the data to be moved off the port. This could be caused if your instrument is missing a handshaking signal, for example. Two VIs that may clear the port are Serial Break.vi and Flush I/O Buffer.vi. I would also suggest using the VISA Status Description.vi after each of these calls to assist in troubleshooting. This VI can be much more descriptive than the LabVIEW error codes.

A better way to fix your problem would be to eliminate the printer from missing the data every once in a while. Perhaps some timing issues may be occurring in your program, a loop delay could possibly help.

Ryan Tamblin
Applications Engineer
National Instruments

[Max]

Rainer,

Maybe you can try the "VISA Flush I/O Buffer" vi (VISA - VISA Advanced -
Interface Specific). It worked on a serial port, but I have no idea if it
works
also on a parallel port. It is worth trying it.
Good Luck.

"rainer" schreef in bericht
news:50650000000800000011270000-993342863000@exchange.ni.com...
> I'm sending image-files to a custom made printing unit via VISA
> through the parallel port.
> Sometimes the unit doesn't accept the file.
> Therefore I need to clear the parrallel port completely and send the
> file again.
> (Right now I'm switching off the unit and waiting for the error
> message from WindowsNT).
> How can I clear the parrallel port via LabVIEW?
> (VISA clear.vi doesn't work, the data is still on the port).