# Modbus to MQTT Bridge Service

A Python service that reads temperature and humidity data from a Modbus TCP server and publishes the data to an MQTT broker.

## 📁 Project Structure

```
POE/
├── config.py           # Configuration constants
├── sensor_bridge.py    # Core logic for Modbus and MQTT operations
├── main.py            # Entry point
├── requirements.txt   # Python dependencies
├── README.md         # This file
├── poe.py            # Original single file (backup)
└── memory-bank/      # Memory bank directory
```

## 🚀 Quick Start

### 1. Install Dependencies
```bash
pip install -r requirements.txt
```

### 2. Configure Settings
Edit `config.py` to match your environment:
```python
# Modbus configuration
MODBUS_HOST = "10.84.48.153"
MODBUS_PORT = 505

# MQTT configuration  
MQTT_BROKER = "mqtt.service.mesh"
MQTT_TOPIC = "Temperature_Humidity"
```

### 3. Run the Service
```bash
python main.py
```

## 📊 Features

- **Modbus TCP Client**: Reads data from Modbus holding registers
- **MQTT Publisher**: Publishes sensor data to MQTT broker
- **Data Processing**: Converts raw sensor values to calibrated readings
- **Error Handling**: Robust error handling and retry mechanisms
- **Logging**: Comprehensive logging for monitoring and debugging
- **Health Check API**: HTTP endpoints for system health monitoring
- **Sensor Status Tracking**: Real-time tracking of individual sensor health
- **Alerting System**: Automatic alerts for sensor failures and recovery
- **Recovery Detection**: Detects when failed sensors come back online

## 📈 Data Format

The service publishes JSON data to the MQTT topic:
```json
{
  "time": "2024-01-15 10:30:25",
  "location": "Office",
  "temperature": 23.5,
  "humidity": 65.2
}
```

## 🔧 Configuration

All configuration is centralized in `config.py`:

| Parameter | Description | Default |
|-----------|-------------|---------|
| `MODBUS_HOST` | Modbus TCP server IP | "10.84.48.153" |
| `MODBUS_PORT` | Modbus TCP port | 505 |
| `MQTT_BROKER` | MQTT broker address | "mqtt.service.mesh" |
| `MQTT_TOPIC` | MQTT publish topic | "Temperature_Humidity" |
| `PUBLISH_INTERVAL` | Data publish interval (seconds) | 10 |
| `LOCATION` | Sensor location identifier | "Office" |

## 📡 Sensor Mapping

- **Register 0**: Temperature (raw value × 0.1 - 40)
- **Register 1**: Humidity (raw value × 0.1)

## 🏥 Health Check & Monitoring

### Health Check Endpoints

The service provides HTTP endpoints for monitoring:

- **http://localhost:8080/health** - Basic service health check
- **http://localhost:8080/sensors** - Detailed sensor status information

### Alerting System

The system automatically sends MQTT alerts for:

- **Sensor Failures**: When a sensor fails 3 consecutive times
- **Sensor Recovery**: When a failed sensor comes back online

Alert topics:
- `sensor-alerts` - Failure and recovery alerts
- `sensor-status/{location}/status` - Individual sensor status updates

### Demo Monitoring Script

Use the demo script to test monitoring features:

```bash
# Check health endpoint
python demo_monitoring.py health

# Check sensors status
python demo_monitoring.py sensors

# Monitor system for 5 minutes
python demo_monitoring.py monitor 300
```

### Configuration Options

| Parameter | Description | Default |
|-----------|-------------|---------|
| `HEALTH_CHECK_ENABLED` | Enable/disable health check server | True |
| `HEALTH_CHECK_PORT` | HTTP server port | 8080 |
| `ALERTING_ENABLED` | Enable/disable MQTT alerts | True |
| `SENSOR_TIMEOUT_THRESHOLD` | Failures before alert | 3 |
| `RECOVERY_CONFIRMATION_COUNT` | Successes to confirm recovery | 2 |

## 🛠️ Maintenance

### Running as a Service

For production deployment, consider running as a system service:

```bash
# Example systemd service file
[Unit]
Description=Modbus MQTT Bridge
After=network.target

[Service]
Type=simple
User=pi
WorkingDirectory=/path/to/POE
ExecStart=/usr/bin/python3 main.py
Restart=always

[Install]
WantedBy=multi-user.target
```

### Monitoring

The service provides comprehensive logging. Monitor the logs for:
- Connection status
- Data reading success/failure
- MQTT publish status
- Error conditions

## 🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test thoroughly
5. Submit a pull request

## 📝 License

This project is licensed under the MIT License.