Hello,

Anyone here have experience controlling the Residential Control Systems RS-485 TR40 Thermostats with the RTI RP6 and CM-232 (RS-232 Communication Module).

I'm using the RCS Model 485PB RS232 to RS485 serial converter that lets you send serial commands to the TR40 Thermostat and provides a 9 Pin serial interface which the CM-232 plugs directly into and looks like it should work and does work when connected to a PC using the RCS software. It uses very simple Ascii commands like A=1, SPH=75, CR to set the temp to 75 degrees. This command works from their software and from Windows Hyperterminal but it does not work when using the RP6 and CM-232.

In the Theatretouch Designer I've set it up as follows:
OUTPUT: RF Trigger Codes for Control System
RS-232: 9600, N, 8, 1
Delay = None (tried some small delays with no success)
Sustain = Tried None and Sustain Checked.
Output Port=6
RS-232 String= A=1, SPH=75, CR

I've tried a null modem adapter and this didn't help.

Also, according to the CM232 guide data is transmitted on Pin 3 and Signal Ground is on Pin 5 which correlates to the pinouts on the RCS 485PB for data transmission and signal ground.

Any help would be appreciated.

Well I got it working but the only thing I did differently was used a separate 24 VAC transformer to the RCS TCU unit and after that it started working with the RS232 commands. It has an option to pull power off the furnace but that was causing the RCS TCU and WDU to lose power intermittently so perhaps that was somehow effecting the RS232-RS485 commands?

Anyways, this setup works very well now and if anyone is interested here's a link to the product.
[Link: resconsys.com]

Thats great :) So let me get this straight, you just had to install an isolated power supply for the TCU?

Yes. I'm powering the TCU with a separate 1000ma 24VAC transformer I bought at Radio Shack for $19.00. I'm guessing the TCU and WDU were pulling too much power from the furnace which kept causing them both too lose power/reboot.

I like the way RCS has 2 separate components to attach to your furnace making it very easy to install, get power to, and run a CAT 5 cable to the RS-232/485 converter located near the RTI RP6.

The WDU replaces the old stat and the original 4 wires go from the WDU (wall display unit) to the TCU (Control Unit) which I mounted next to the furnace. Then the TCU connects to the furnace and looks to the furnace like a stat. It also has the 485 connection on the TCU which I ran CAT 5 from to the RS-232 to RS-485 converter located next to the RTI RP6.

Davahad,

Thanks for all the info. I was researching Thermostats to integrate with my RTI. Your posts were very timely and helpful.

-Nik =B^)

One more thing on sending commands. For some reason the RCS RS-232 to 485 adapter will not accept commands until you send a command from the RTI that includes a \r at the end of the command line.

For example:

A=1, SPH=75, CR \r

If you try A=1, SPH=75, CR without the \r this will not work until you have sent 1 command with the \r. After that none of the commands need the \r.

Don't know why this is but that's how I got it to work. Perhaps it has something to do with the RTI RP6?