Real-time Data Monitoring: Sensors, timers, outputs, runtime hours, water counters
Selective Data Retrieval: Bandwidth-optimized API for specific data groups/keys
Asynchronous Control Operations: DTS start/stop/skip sequences with progress tracking
Background Data Updates: Continuous PLC monitoring with configurable intervals
Thread-safe Data Caching: Centralized cache with concurrent access support
Comprehensive Error Handling: Structured error responses and logging
Modular Architecture: Clean separation of concerns with service layers

Quick Start

Installation

# Clone repository
git clone <repository-url>
cd watermaker-plc-api

# Install dependencies
pip install -r requirements.txt

# Install package
pip install -e .

Configuration

Set environment variables:

export PLC_IP=198.18.100.141
export PLC_PORT=502
export DATA_UPDATE_INTERVAL=5
export LOG_LEVEL=INFO

Running the API

# Using the command line entry point
watermaker-api --host 0.0.0.0 --port 5000

# Or run directly
python -m watermaker_plc_api.main

API Endpoints

Data Monitoring

GET /api/status - Connection and system status
GET /api/all - All PLC data in one response
GET /api/select - Selective data retrieval (bandwidth optimized)
GET /api/sensors - All sensor data
GET /api/timers - All timer data
GET /api/outputs - Output control data
GET /api/runtime - Runtime hours data
GET /api/water_counters - Water production counters

Control Operations

POST /api/dts/start - Start DTS watermaker sequence (async)
POST /api/dts/stop - Stop watermaker sequence (async)
POST /api/dts/skip - Skip current step (async)
GET /api/dts/status - Get DTS operation status
POST /api/write/register - Write single register

Selective API Examples

# Get temperature and pressure sensors only
curl "http://localhost:5000/api/select?groups=temperature,pressure"

# Get specific registers
curl "http://localhost:5000/api/select?keys=1036,1003,1017,1121"

# Combined approach
curl "http://localhost:5000/api/select?groups=dts_timer&keys=1036"

Control Examples

# Start DTS sequence (returns immediately with task_id)
curl -X POST http://localhost:5000/api/dts/start

# Poll for progress
curl http://localhost:5000/api/dts/status/abc12345

# Stop watermaker
curl -X POST http://localhost:5000/api/dts/stop

Architecture

watermaker_plc_api/
├── app.py                 # Flask application factory
├── config.py              # Configuration management
├── controllers/           # API route handlers
├── services/              # Business logic layer
├── models/                # Data models and mappings
└── utils/                 # Utilities and helpers

Key Components

PLCConnection: Thread-safe Modbus TCP communication
DataCache: Centralized, thread-safe data storage
RegisterReader: Service for reading PLC registers
RegisterWriter: Service for writing PLC registers
BackgroundTaskManager: Continuous data updates
Controllers: RESTful API endpoints

Variable Groups

Group	Description	Count
system	System status and mode	2
pressure	Water pressure sensors	3
temperature	Temperature monitoring	2
flow	Flow rate meters	3
quality	Water quality (TDS) sensors	2
fwf_timer	Fresh water flush timers	1
dts_timer	DTS process step timers	6
rtc	Real-time clock data	6
outputs	Digital output controls	6
runtime	System runtime hours	1
water_counters	Water production counters	4

Development

Running Tests

python -m pytest tests/

Environment Setup

# Development environment
export FLASK_ENV=development
export DEBUG=true
export PLC_IP=127.0.0.1  # For simulator

# Production environment
export FLASK_ENV=production
export SECRET_KEY=your-secret-key
export PLC_IP=198.18.100.141

License

MIT License - see LICENSE file for details.