Arduino Modbus TCP Client (Ethernet)

This project demonstrates how to use an Arduino MKR board with MKR ETH Shield as a Modbus TCP Client.
It connects to a Modbus TCP Server over Ethernet and performs coil write and holding register read operations for sensors like Temperature & Humidity (T&H), CO₂ sensors, and Energy Meters (L&T Wh).

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✨ Features

• 📡 Implements Modbus TCP client over Ethernet
• 🔗 Connects to any Modbus TCP server (port 502)
• 🖊️ Supports coil write operations
• 📖 Reads holding registers (16-bit / float)
• 🏭 Tested with industrial Modbus TCP devices

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🔧 Hardware Required

• Arduino MKR Board (e.g., MKR Zero, MKR WiFi 1010)
• MKR ETH Shield
• Ethernet cable + Local Modbus TCP server device (PLC, Energy meter, Simulator)

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📡 Network Configuration

Update your board’s network details in the sketch:

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(192, 168, 33, 65);
IPAddress gateway(192, 168, 33, 1);
IPAddress subnet(255, 255, 255, 0);
IPAddress server(192, 168, 33, 60);  // Modbus server IP