Modbus RTU over RS-485 is the serial workhorse of industrial field wiring — the variant you'll meet when connecting an ESP32 directly to an energy meter, PLC, VFD, or temperature transmitter over a wired bus. This tutorial walks through wiring the hardware, installing a library, and flashing working RTU master code.
What You'll Build
A Modbus RTU master on ESP32 that polls holding registers from an RS-485 slave device over a wired bus.
An understanding of register types, addressing, and the reliability practices that separate a demo from a production deployment.
Prerequisites
