Serial cable present?

[Bill Symonds]

Hi all

Is there a VI I can use in Labview (5) to interrogate the serial port and
determine if a CTS present. I need to do this to determine whether or not
there is a serial cable connecting the PC to an instrument (which
generates the CTS).

I've tried a serial write but if there is no cable the VI either stalls
(if hardware handshaking is enabled since there is no CTS) or just runs
without generating an error if there is no handshaking.

The other approach would be to stop the VI from running if the write VI
stalls but I haven't figured out how to do that either.

Reading the NI knowledge base I think I need to access my serial port
register using the inport/outport functions, but I've not tried this
before so any advice
would be gratefully received!

Many thanks in advance.

Bill
mailto:wsymonds@clara.co.uk

[Kevin_work]

Bill Symonds wrote:

> Hi all
>
> Is there a VI I can use in Labview (5) to interrogate the serial port and
> determine if a CTS present. I need to do this to determine whether or not
> there is a serial cable connecting the PC to an instrument (which
> generates the CTS).
>
> I've tried a serial write but if there is no cable the VI either stalls
> (if hardware handshaking is enabled since there is no CTS) or just runs
> without generating an error if there is no handshaking.
>
> The other approach would be to stop the VI from running if the write VI
> stalls but I haven't figured out how to do that either.
>
> Reading the NI knowledge base I think I need to access my serial port
> register using the inport/outport functions, but I've not tried this
> before so any
advice would be gratefully received!
>
> Many thanks in advance.
>
> Bill
> mailto:wsymonds@clara.co.uk

Try looking at the VISA drivers, I believe you can
check the state of some of the control lines
I believe that CTS is one of them.
Kevin Kent