SK120x Web Controller (ESP32 + RS485 + Modbus)

This project provides a web-based controller for the SK120X DC Regulated Power Supply DC-DC Step Up/Down Converter using an ESP32, RS485 transceiver, and Modbus RTU.

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✨ Features

• 📡 WiFi connectivity (station or fallback access point mode)
• 🌐 Embedded web interface (HTML/CSS/JS served directly from ESP32)
• ⚡ Live monitoring of:
  • Set Voltage / Current
  • Output Voltage / Current / Power
  • Output state (ON/OFF)
  • MPPT (experimental)
• 🎛️ Remote control of:
  • Voltage & Current setpoints
  • Output toggle
  • MPPT enable/disable
• 📊 Built-in charts:
  • Voltage/Current history line chart
  • Voltage histogram
• 🔍 Register scanner with CSV export
• 🛠️ Modular HTML UI (panels, gauges, seven-segment style readouts)

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🖥️ Web Interface Preview

• Top Row: Current status, setpoints, toggle controls
• Middle Row: Voltage/Current history chart, histogram
• Bottom Row: Modbus register scanner with CSV export

The UI is entirely self-contained (no CDN or external JS), ensuring it works offline once loaded.

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⚙️ Hardware Setup

• ESP32 development board
• RS485 transceiver module (DE/RE control supported, configurable)
• SK120X DC-DC Power Supply

Pin Mapping (default):

Signal	ESP32 Pin
UART RX	16
UART TX	17
RS485 DE/RE	4
Baudrate	115200

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🔌 Software Setup

1. Install Arduino IDE with ESP32 board support
2. Install libraries:
   • ModbusMaster
   • WebServer (comes with ESP32 Arduino core)
3. Update your WiFi credentials in the sketch:

   const char *WIFI_SSID = "YOUR_WIFI_SSID";
   const char *WIFI_PASS = "YOUR_WIFI_PASSWORD";

Compile & upload to your ESP32.

Open Serial Monitor to see IP address (or connect to fallback AP SK120x-ESP32).

Navigate to the IP address in your browser to access the web UI.

📡 API Endpoints

GET / → Web UI

GET /api/status → JSON with live status

POST /api/write?reg=X&val=Y → Write Modbus register

GET /api/scan?start=A&end=B → Scan Modbus registers

📝 Notes

MPPT support is experimental – some SK120x firmware revisions may not implement it.

Register scanner helps discover unknown registers and their values.

The project mimics LabVIEW-style panels for readability and modular control.

📚 Resources

SK120X DC Power Supply on Amazon

📜 License

MIT License – free to use, modify, and share.