Add Command / Telegram to set current temperature of thermostat

[JelleRoets-Work]

Is your feature request related to a problem? Please describe.
My setup consist of a Bosch Boiler Condens 7000iW, Bosch Thermostat CW400 and a Bosch MM200 mixing module with 2 pumps. The main thermostat (CW400) is installed in the living and controlling the first circuit installed in the living room.
However it is also controlling the 2nd circuit, which is connected to other different rooms in the house, but still using the measured living room temperature as current temperature, which does not make sense of course.

So to solve this, I installed extra temperature sensors in the other rooms and connected them to Home assistent.
With the E32 Gateway I can already overwrite the setpoint temperature for both the first and second circuit. However I cannot set the actual current room temperature of the 2nd circuit with the measured value of my temp sensors.

Describe the solution you'd like
A command / telegram to set the current temperature of the 2nd circuit in the CW400 thermostat, if possible.

Describe alternatives you've considered

1. I could directly control the 2nd pump status from Home Assistent. However this way Home Assistent will act as a thermostat, while that is not the intention. Moreover, most likely the CW400 will still try control the 2nd circuit as well and probably overwrite my manual updates to the pump status.
   
2. Buy an extra Bosch CR10 thermostat, that can act as a remote control for the main CW400. But actually this wouldn't work as there is no bus wire available in the other rooms and I would have to buy one for each extra room. So then I should buy the EasyControl with CT200, which is way too expensive.

But since the CR10 can act as a remote for the CW400, I guess it's possible to externally set the current temperature of a 2nd circuit. So hopefully we can mimic that with some command(s) from the E32 Gateway.

Thanks for any help, suggestions

[MichaelDvP]

Some people have a wireless room sensor, see #103, #356, #624. This sensor sends from device-id 0x40 the temperature as broadcast in telegram 0x435. There is also a wireless base connected at device 0x50, not sending anything.
I don't know if something has to be configured to activate the sensor, also this is for hc1, don't know if hc2 uses different device-id (0x41?) or/and different telegram. Also unknown if the base communicates on startup to configure the sensor.
If we know what to send, we can emulate such a sensor. these people all have IVT rego thermostats, this is mainly compatible with RC300/CW400, but maybe not full compatible. Don't know if this sensor fits to your thermstat.

As you mentioned a roomcontroller can be used as remote. For RC35 with RC20 remote we have a emulation for RC20 integrated in ems-esp, This works fine, i use it. But for CW400 there is to little information yet. In #590 a RC100H is used as remote for hc1. The remote thermostat is on device-id 0x38 and sends message 0x42B (temp) and 0x47B (hum) to the thermostat at 0x10. But also unclear how to configure this for a different hc, I guess a RC100 will use device 0x18 and only 0x42B (or a different telegram).
From RC20 remote we know that the remote differs only in device-id hc1:0x18, hc2:0x19, etc.) and always uses the same telegram 0xAF. But for RC300/CW400 this could be different.

If you can get a CR10 (or wireless snesor) for testing, you can log and configure the remote for hc2. With this log we add it to the roomcontrol file https://github.com/emsesp/EMS-ESP32/blob/dev/src/roomcontrol.cpp.
The logic for the emulation is simple: send a valid temperature to thermostat/hc2/remotetemp and the emulation starts sending this temperature every minute to the main thermostat as remote thermostat, sending a invalid value (-1, 101) to remotetemp stops emulation.

[JelleRoets-Work]

Thanks for this extensive explanation. I'll see what I can do, I'll investige myself a bit and if necessary will buy a CR10 (just for reference) and spoof the EMS bus to see what happens.