Write value to ESPHome modbus server

ESPHome
1

Hi. I made an ESPHome modbus RTU slave device, and i can read holding register values with an external client. But how is possible to write to this register? Can’t figure out. Here is my config:

number:
  - platform: template
    name: "slider"
    id: slider
    optimistic: true
    min_value: 0
    max_value: 200
    step: 1   
    
uart:
  - id: intmodbus
    tx_pin: 21
    rx_pin: 20
    baud_rate: 9600
    stop_bits: 1
    data_bits: 8
    parity: NONE
    debug:
      direction: BOTH

modbus:
  uart_id: intmodbus
  id: modbus_server
  role: server
  flow_control_pin: 5  

modbus_controller:
  - modbus_id: modbus_server
    address: 1
    server_registers:
      - address: 1
        value_type: S_WORD
        read_lambda: |-
          return id(slider).state;
2

Documentation doesn’t give any function for that.
I’m pretty sure you have better chances for help on Discord.
If you find answer, remember to update here.

3

There is active development for this capability on discord.

Try GitHub - gotnone/esphome at server_write_registers as an external_component. You will need to grab the components [core, modbus, modbus_controller]