GPI via RS232 Port

jabramson wrote: »

I have a device that I would like to trigger via GPI, however it does not have a standard contact closure GPI trigger. It is instead triggered by shorting pins on the RS-232 port (which is a new one to me)

Is this something that can be done in a netlinx master via code and a rs-232 port (not VIA the GPI ports)? I'm thinking no, but it's worth asking.

User Manual For Device, page 110: http://www.digital-rapids.com/downloads/docs/Stream3.7_Users_Guide.pdf

On page 110 of the document you included there is a diagram on how to do this.

Basically, connect pins 2, 3, and 5 of your preferred AMX RS232 port to pins 2, 3, and 5 of your devices RS232 port with 2 and 3 connected as appropriate (null or straight). This will give you your RS232 control.

Connect two relays as shown in the diagram: one between 5 (relay gnd) and pin 6 on the device's RS232 port and the other between 5 and pin 8 on the device's RS232 port.

Connect the resistors as shown.

Your RS232 will be sent out the AMX RS232 port as normal and you actuate the relays for the GPI (whatever that is).

With just the RS232 port: no. With IO ports instead of relays? IO ports do not provide a "dry contact" closure. Whether or not the IO port will be detected as a contact closure depends on the circuit at the other end so you would have to try it. Also, check to make sure that the port does not provide an undesirable open circuit voltage. In my experience, they usually work in creating a contact closure but there have been a couple times when they didn't. Several years ago there was a discussion here about relay controlled two port Kramer switchers and the inability to get them to switch when using IO ports as relays. The solution was to trigger a small inexpensive relay with the IO port. There have been several discussions about that within the last several months. Both David Hawthorne and Vining have recommended what appear to be reliable and very inexpensive relay boards which will provide "dry contact" closures when triggered by an IO port. THey come several to a board and can be separated out individually.

added:

Here they are at not much more than $5 per relay including shipping:
http://www.amazon.com/Altronix-RB610-12-24vDC-Break-Away-Relay/dp/B0006TVW9S