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


The `modbus` sensor allows you to gather data from [Modbus](http://www.modbus.org/) registers.

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

```yaml
# 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.
  - **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, float). If float selected, value will be converted to IEEE 754 floating point format. default int

It's possible to change the default 30 seconds scan interval for the sensor updates as shown in the [Platform options](/docs/configuration/platform_options/#scan-interval) documentation.

### {% linkable_title Full example %}

Example a temperature sensor with a 10 seconds scan interval:

```yaml
sensor:
- platform: modbus
  scan_interval: 10
  registers:
    - name: Room_1
      slave: 10
      register: 0
      register_type: holding
      update_interval: 2.5
      unit_of_measurement: °C
      count: 1
      scale: 0.1
      offset: 0
      precision: 1
      data_type: int
```