Serial read for three different wires!

[Mauricio]

Dear Sirs:

Actually I have a device which "puts" a signal in one of the three different
"cables" available according to its state. The signal is the same so I can't
mix it in any way (I think).

What I should do is to read the state of the device using a PC which runs
Labview 7. The device doesn't perform any protocol; it just places a signal
for a short period of time.

I have been told I can achieve it using the Serial port (That was all the
help!). I can't use the parallel because it is used by another device.

As far I have investigated, the serial port has one (just one!) cable to
read (Pin 2). How can I get the remaining two lines?

Also I have checked that the loopback test works fine. But I haven't been
able to read any sig
nal. Can I use the serial port without any of the
parameters present on the Serial Read VI from Labview?

I would appreciate any help on this matter.

Very best regards,

Mauricio

[Dennis_Knutson]

Normally, serial data is only present on the Receive Data line of the serial port (that's why it's serial communication and not parallel). There are other input lines of a serial port that are normally used for handshaking. They are Data Carrier Detect (1), Data Set Ready (6), Clear To Send (8), and Ring Indicator (9). You can wire your three different signals from the device to a single RS-232 cable and use any three pins that you want. Instead of using the serial read, you would use a VISA property function and choose Modem Line Settings. Then pick the specific line that you've wired the signals to.

[Mauricio]

Dennis:

Thank you so much for your kind response.

One question about the implementation: From where does the Property Node
should get the reference? from the VISA SERIAL CONFIGURATION VI?

Thank you again.

Mauricio

"Dennis Knutson" wrote in message
news:5065000000050000005C1C0100-1042324653000@exchange.ni.com...
> Normally, serial data is only present on the Receive Data line of the
> serial port (that's why it's serial communication and not parallel).
> There are other input lines of a serial port that are normally used
> for handshaking. They are Data Carrier Detect (1), Data Set Ready (6),
> Clear To Send (8), and Ring Indicator (9). You can wire your three
> different signals from the device to a single RS-232 cable and use any
> three
pins that you want. Instead of using the serial read, you would
> use a VISA property function and choose Modem Line Settings. Then pick
> the specific line that you've wired the signals to.

[Mauricio]

I found out the answer. The REFERENCE goes wired to the VISA SERIAL
CONFIGURATION VI.

It worked fine after installing the VISA Runtime from the second CD
(Drivers).

"Mauricio" wrote in message
news:3f502623@newsgroups....
> Dennis:
>
> Thank you so much for your kind response.
>
> One question about the implementation: From where does the Property Node
> should get the reference? from the VISA SERIAL CONFIGURATION VI?
>
> Thank you again.
>
> Mauricio
>
> "Dennis Knutson" wrote in message
> news:5065000000050000005C1C0100-1042324653000@exchange.ni.com...
> > Normally, serial data is only present on the Receive Data line of the
> > serial port (that's why it's serial communication and not parallel).
> > There
are other input lines of a serial port that are normally used
> > for handshaking. They are Data Carrier Detect (1), Data Set Ready (6),
> > Clear To Send (8), and Ring Indicator (9). You can wire your three
> > different signals from the device to a single RS-232 cable and use any
> > three pins that you want. Instead of using the serial read, you would
> > use a VISA property function and choose Modem Line Settings. Then pick
> > the specific line that you've wired the signals to.
>
>