Integrating to multiple self-contained/complex ModBus thermostats

Third party integrations
1

Hi,

I’m just starting my journey with HA. It looks like it is flexible enough to cater for my needs, but probably with some code. I’m quite competent with Python, but need guidance with the overall approach.

I have a single RS485 Modbus network which has three types of devices on it:

  • Thermostats (4x) which control floor heating, two also control ceiling fans (3 speeds), all via 24VAC relay contacts. These devices have a full 7-day/4-phase calendar, heat and cool modes, set temperatures, time-of-day display, room and floor temperature measurement and external temperature display;
  • Reverse cycle air conditioner (2x) with set temp, fan speed, return air temp measurement;
  • Awning controller, with position control and position readout.

I want HA to be able to access all these functions, to give me remote control, reprogram the thermostats seasonally, link the aircons with the thermostats, etc. But I don’t want to diminish the interface direct to the thermostats - they and HA should work together.

This question is about how I model the thermostats to expose all their capability into HA. Do I need to write a Python module, obstensibly like https://github.com/home-assistant/core/blob/75615bd92a8380b4d3f25834701d910a6e239663/homeassistant/components/modbus/climate.py, which picks up all the ClimateEntity interfaces, but also inherits from other entities like FanDevice, SwitchEntity, etc. and implements those interfaces? Or is it done some other way?

And I don’t see entities representing things like a clock (for time-of-day setting) or the calendar.

I have full ModBus register descriptions, so there are no issues there. But some code showing the necessary module structure and interfaces that illustrates the overall appreach would be very helpful.

Thanks.

2

did you ever find a path for this, I am running april aire 8800s and looking to do the same thing intergrating them into HA

3

Hello Trenton,

To be honest some other projects popped up and I didn’t get back to this; and since my motivation for using HA was out-of-house remote control, the continued work-from-home orders here (now just lifting) reduced the need.

I’m still interested to pursue this and would want to review any new documentation and other integrations to see if and how this sort of complex device integration is possible. If you (or anybody) has any insights into this, I’d love to see it.

Daniel

4

I am able to talk to and control all the functions on my april aire thermostats Via terminal window over the 422/485 protocol and have april aire documentaion on programming and commands used, I just don’t have the knowledge of writing any python or whatever is needed to make it work in Home assistant and finding someone that knows how to write a intergration and willing to has proven daunting the thread I started on this

Aprilaire Thermostat 8800 any MODBUS experts?