1.5 KiB
1.5 KiB
System Patterns
System Architecture
- Single-process, event-driven script: The application runs as a single Python process, using a main loop to periodically read from Modbus and publish to MQTT.
- Polling pattern: Data is acquired from the Modbus device at a fixed interval (configurable via
PUBLISH_INTERVAL). - Bridge pattern: The script acts as a bridge between two protocols (Modbus TCP and MQTT), translating and forwarding data.
Key Technical Decisions
- Direct variable configuration: All connection and operational parameters are set as variables at the top of the script for simplicity.
- Error handling and reconnection: The script checks and re-establishes connections to both Modbus and MQTT as needed, with logging for all failures.
- JSON formatting: Data is published in pretty-printed JSON for readability and ease of integration.
- Separation of concerns: Reading/publishing logic is encapsulated in a dedicated function (
read_and_publish_data), while the main loop handles orchestration and lifecycle.
Design Patterns
- Callback pattern: Used for MQTT events (on_connect, on_publish).
- Try/except/finally: Used for robust error handling and resource cleanup.
- Headless operation: No UI; all feedback is via logs and MQTT messages.
Component Relationships
- The Modbus client and MQTT client are instantiated and managed independently, but coordinated within the main loop.
- Data flows from Modbus -> Python processing -> MQTT publish.