Serial POLL

[Henrik Skupin]

Hi again,i wants to read the status of a device which is connected over RS232. Therefor i use VISA.Inside the palette i found the SLB-Vi which polls the port to get the status. When i run the program i only get an error with no detailed information. I know that it works with polling the device cause the older version was written in BASIC and uses also this method.Could somebody plz help me!!?RegardsHenrik

[Johannes Niess]

Henrik Skupin writes:

>
>
> Hi again,
>

i wants to read the status of a device which is connected over RS232.
> Therefor i use VISA.
>
Inside the palette i found the SLB-Vi which polls the port to get the
> status. When i run the program i only get an error with no detailed information.
> I know that it works with polling the device cause the older version was
> written in BASIC and uses also this method.
>
Could somebody plz help me!!?
>

Regards
>
Henrik

Henrik,

well behaved instruments don't need polling. Use VISA read for lets
say 1000 bytes and it will return the bytes until the first linefeed or
1000 bytes maximum.

If you definitely nedd pollin
g, use the visa property
node/serial/bytes at serial port.

HTH

Johannes Niess

P.S: My beta version of VISA (nivisa-2.0.1-2.i386.rpm ?) has problems
with closing (serial) sessions on stop (Red button). It sometimes says
"resetting vi" and that is running forever. The only remedy is
"killall labview".