Modbus_controller issues with custom functions (Wavin AHC 9000)

[heinekmadsen]

Hi Martin…

I’m writing you since you have done a whole lot of work on the modbus_controller for ESPhome.
I’m having some issues with a device which uses some non standard functions for modbus.
It’s the Wavin AHC 9000 floor heating system, which has a control unit and remote wireless thermostats in each room.

Using the modbus_controller, I’m able to read the following data from each channel (up to 16) from the control unit

• Current temperature in the room
• Target temperature on the thermostat in the room
• Battery level on the thermostat in the room
• Standby state of the thermostat/channel on the control unit
  (When standby in on the thermostat will only keep the floor at a set standby temperature (i.e.. 5 degrees Celsius), and when its off it’s automatically heating when needed to obtain the target temperature)

So here’s my current issues…. (only two)

1. Standby state
   When reading the standby state on an active (Standby off) thermostat it’s working just fine using a switch with modbus_controller with custom_command

When I change the standby state to on, on the physical thermostat, it the reads the change and sets the switch to on in ESPhome/Home Assistant, which is expected as the standby mode is now active.
At the next update interval, it reads the standby state again, but then it’s read as off, and the physical thermostat standby state is reverted to off.
This happens all buy itself without any user interactions.
What expected is for the thermostat to stay in standby on state until it’s either turned back off either on the physical thermostat or from ESPhome/Home Assistant.

            I have a custom mqtt solution where the behavior is not happening. Using that code keeps the thermostat standby state in on until it’s changed from Home Assistant or on the physical thermostat
            Here’s the working mqtt code: heinekmadsen/Wavin-AHC-9000-mqtt: Esp8266 mqtt interface for Wavin AHC-9000/Jablotron AC-116 (github.com)

2. Target temperature
   Writing a new target temperature with a modbus_controller number.
   I can successfully get the number to show the target temperature using custom_command

When I change the number I need to write the new value with a function code 0x44, but that doesn't seem to be possible with modbus_controller number write_lambda.
As I see it, the modbus_controller switch has write_lambda where I can create the data arrays using payload.push_back, but the number seems to don’t care about that when using write_lambda.

Any ideas, hints or assistance is much appreciated. I know for a fact, that there are many users of this system here in Denmark, and it’s also known as a Jablotron AC-116 system.
I can arrange supervised remote access if needed for troubleshooting.

Please let me know if you can/will be able to assist.
You can reach me here on github or discord.
Discord: TjaLfE#7483

Kind regards,
Heine