Push POE project

memory-bank/systemPatterns.md

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+# 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.