home-assistant.io/source/_components/sensor.modbus.markdown

layout	title	description	date	sidebar	comments	sharing	footer	logo	ha_category	ha_release	ha_iot_class
page	Modbus Sensor	Instructions on how to integrate Modbus sensors into Home Assistant.	2015-08-30 23:38	true	false	true	true	modbus.png	Sensor	pre 0.7	Local Push

The modbus sensor allows you to gather data from Modbus registers.

To use your Modbus sensors in your installation, add the following to your configuration.yaml file:

# Example configuration.yml entry
sensor:
  platform: modbus
  registers:
    - name: Sensor1
      unit_of_measurement: °C
      slave: 1
      register: 100
    - name: Sensor2
      unit_of_measurement: mg
      slave: 1
      register: 110
      count: 2
    - name: Sensor3
      unit_of_measurement: °C
      slave: 1
      register: 120
      register_type: input
      data_type: float
      scale: 0.01
      offset: -273.16
      precision: 2

Configuration variables:

• registers array (Required): The array contains a list of relevant registers to read from.
  • name (Required): Name of the sensor.
  • slave (Required): The number of the slave (Optional for tcp and upd Modbus).
  • register (Required): Register number.
  • register_type (Optional): Modbus register type (holding, input), default holding.
  • unit_of_measurement (Optional): Unit to attach to value.
  • count (Optional): Number of registers to read.
  • reverse_order (Optional): Reverse the order of registers when count >1, default False.
  • scale (Optional): Scale factor (output = scale * value + offset), default 1.
  • offset (Optional): Final offset (output = scale * value + offset), default 0.
  • precision (Optional): Number of valid decimals, default 0.
  • data_type (Optional): Response representation (int, uint, float, custom). If float selected, value will be converted to IEEE 754 floating point format. Default int.
  • structure (Optional): If data_type is custom specify here a double quoted python struct format string to unpack the value. See python documentation for details. Ex: ">i".

It's possible to change the default 30 seconds scan interval for the sensor updates as shown in the Platform options documentation.

{% linkable_title Full example %}

Example a temperature sensor with a 10 seconds scan interval:

sensor:
- platform: modbus
  scan_interval: 10
  registers:
    - name: Room_1
      slave: 10
      register: 0
      register_type: holding
      unit_of_measurement: °C
      count: 1
      scale: 0.1
      offset: 0
      precision: 1
      data_type: int