Use real room temperature with Homematic HG-HM-CC-RT-DN

Setup, Configuration and Use Beginners
1

Dear forum,

I successfully installed openhabbian on my raspberry pi 3 and got my homatic HG-HM-CC-RT-DN heating controller working with openhabian. I can read the measured temperatur and set the wanted temperature via rules and the UI.

But my problem is that in my living room there is a board over the heater so that the air is stuck a little and the HG-HM-CC-RT-DN measures really hight tempearatures and therefore I have to set high temperatures in the UI, i.e. to 24°C to achieve ~20°C. Due to the stuck, hot air, there is no real offset i could use to calculate the desired set temperature.

Because I also want to establish a presence detection via bluetooth, I came up with the idea to measure the room temperature separately by installing a raspberry pi W and connect a temperature sensor to it and use its bluetooth ability to scan for my mobile phone.

So I bought two raspberry pi W and the temperature sensors. I finally got it working. The raspberry pi W can read the temperature and, via bash script, the temperature is send to the openhab via WLAN and the REST API.

Now, I would like to use my measured temperature, acquired by the raspberry pi W, to

a) override the measured temperature of the HG-HM-CC-RT-DN

or

b) control the valve state by myself (with a rule).

But neither works. I used a setpoint statement in a rules file to set the valve state, but nothing happend. And I tried to use setpoint to set (override) the temperature of the HG-HM-CC-RT-DN. But that also diddn’t work. No change in the valve state.

Is there any way to let the HG-HM-CC-RT-DN know the excact temperature provided by the raspberry pi W or set the valve state by a rule? I could not find any solution for that so far. Does anyone have another idea to solve the problem? I know that is possble to link a HG-HM-CC-RT-DN with a homematic temperature sensor when a ccu is used, but I use a raspberry pi 3 with a CUL srtick.

Any help is highly apreciated!

Thanks in advance!

2

It’s not possible. You can’t inject the temperature. And you can’t set the valve state.

The solution is to buy the Homematic Wall thermostat kit (34,95€). Build time 5 minutes, no soldering, just clicking parts together. Works like a charm. I am running one of these in every room.

I don’t use a ccu2 as well. Homegear & Homematic Konfigurator let’s you create direct links.

1 Like
3

It should be possible to set an offset temperature for a HM-CC-RT-DN using the CCU UI. The offset can tell the HM-CC-RT-DN to heat until it measures a higher (or lower) temperature than the current setpoint is. E.g. if you have an offset of +2 degrees and a setpoint of 20 degrees it will heat up until it measures 22 degrees internally.

With a bit of scripting it should also be possible to set the offset via Homegear.