Homebrew Weishaupt control based on Tado

Hi,

We have a Weishaupt WTC-32 which uses eBUS but is unfortunately not supported by Tado. There are smart TRVs on all the radiators and I programmed the Weishaupt thermostat in the living room to provide heat whenever one of the TRV's was scheduled to heat a room. While this seemed to work fine I've noticed that when the TRV's in the living room are closed, the WTC regularly starts burning in a futile attempt to heat the living room.

This had to be fixed ! First step was to get an eye on the eBUS between the WTC and its thermostat. I've built an eBUS adapter and used ebusd and reverse engineered message definitions available on GitHub: https://github.com/john30/ebusd and https://github.com/J0EK3R/ebusd-configuration-weishaupt Works great!

The WTC can support multiple thermostats. It will provide heat according to the one with the highest needs. With ebusd and the message definitions I can act as an additional thermostat. There's really only one parameter to send: the temperature of the water going to the radiators. The original thermostat has been set to 'summer mode' but it still handles the hot tapwater.

The Tado state is fetched from the internet via the unofficial API. From this I get the current_temperature, the wanted_temperature and the heating_power for each room. A very simple formula is used to derive the temperature of the radiator water, a linear mapping of the highest heating_power to 30-55 degC.

T = (max(heating_power) / (55 - 30)) + 30

So far it works fine without taking the wanted_temperature or outside temperature into account:

Any suggestions to improve this simple (naive) scheme are greatly appreciated !