Siemens S7 MQTT

A bridge between Siemens S7 PLCs and MQTT, designed for home automation integration with platforms like Home Assistant.

Features

• Connect to Siemens S7 PLCs
• Expose PLC values to MQTT
• Control PLC outputs via MQTT
• Auto-discovery for Home Assistant
• Support for various device types:
  • Lights (on/off)
  • Dimmable lights

Installation

# Clone the repository
git clone https://github.com/jonasclaes/siemens-s7-mqtt.git
cd siemens-s7-mqtt

# Install dependencies
pnpm install

# Build the project
pnpm run build

Configuration

Create a config.json file in the root directory, following the schema defined in config.schema.json. Example:

{
  "$schema": "./config.schema.json",
  "mqtt": {
    "url": "mqtt://username:password@broker.example.com:1883"
  },
  "controllers": [
    {
      "s7": {
        "host": "192.168.1.10",
        "port": 102,
        "rack": 0,
        "slot": 1
      },
      "devices": [
        {
          "type": "light",
          "id": "unique-id-1",
          "friendlyName": "Living Room Light",
          "command": {
            "on": {
              "address": "DB1,X0.0"
            },
            "off": {
              "address": "DB1,X0.1"
            }
          },
          "status": {
            "on": {
              "address": "DB1,X2.0"
            }
          }
        }
      ]
    }
  ]
}

Configuration Schema

The configuration follows a JSON schema that defines:

• MQTT broker connection details
• S7 PLC connection parameters
• Device definitions with addresses for inputs and outputs

Usage

# Start the service
pnpm start

# For development with auto-reload
pnpm run dev

PLC Addressing

The application uses the nodes7 library for S7 communication. Address formats:

• DBx,Xy.z - Bit at position z of byte y in data block x
• DBx,By - Byte y in data block x
• DBx,Cy - Char at byte y in data block x
• DBx,Iy - 16-bit integer at byte y in data block x
• DBx,DINTy - 32-bit integer at byte y in data block x
• DBx,Ry - Real (float) at byte y in data block x

Development

# Run tests
pnpm test

# Run tests with watch mode
pnpm run test:watch

# Generate code coverage
pnpm run test:coverage

# Generate TypeScript types from schema
pnpm run generate:config-schema

Contributing

Please see CONTRIBUTING.md for details on how to contribute to this project.

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.