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