Elk-M1XSP and RCS TR16 thermostat


New Member

I am trying to setup the RS-485 link between the M1XSP and a RCS TR16 thermostat.

The thermostat and the control unit communicate to the HVAC without any problem, all is well on this side. I can get the HVAC to respond to whatever I set on the thermostat.

On the Elk-M1XSP, I can see that is it enrolled in ElkRP, I see the address, the model, and the different version (HW=0.3, Boot=1.0.4, FW=1.0.50), so I guess the cabling is fine on this end also...

In the interface I can set the name of my thermostat, and on my keypad I see the name appear. But the temperature shown is -17, which is telling me that it is not getting the information for the TR16...

So the problem seem to be that I don't seem to have any communication between the M1XSP and the TR16.

The only other thing I can observe, is that the light on the M1XSP is blinking, about 1/2 a second followed immediately by a very fast blink, then about 1/2 a second pause

I doublechecked my cabling connection many times and I even change the TR16 completely, because I though the unit was deffective.... But I cannot make it work.

I guess the next step would be to diagnose the RS-485 communication between the 2 of them, but how do I go about doing that ?

Any ideas, experiences or pointers you could give me would be useful, I really want this to work....

Thank you !

Richard Savage


Senior Member
All I can say is, i've been there. Mine was a defective control unit, but since you have replaced that, not sure I have any answers for you. I am running older firmware (1.0.42 Standard) than you and I have a TR40 vs. the TR16. I have a blinking light on the XSP and on the TR40 control unit (Status), blinking every second or so. XSP is address 1.

Here are some pics I took of my setup (click for larger versions), hope it helps...



New Member
Thanks for the reply and the photos...

1. I am using cat5 cable for my connection between the XSP and the Control unit, could that be a problem ?
2. How can I make sure that my XSP is not deffective ?
3. If my connection from the XSP to the 485 Bus of my Elk system is wrong, I assume that I wouldn't be able to enrole it, right ?
4. Is there a way to construct a 485 to 232 adapter to be able to connect the control unit to a PC a help me diagnose it ?
5. DO you know how can I contact RCS support to get some help ?

Thank you again !