PLC Based Dual-Axis Solar Tracking System

Abstract

This project developed a smart solar tracking system that automatically follows the sun across the sky to capture more sunlight than a fixed panel which signifies more energy. Instead of using simple hobby electronics, the system was built with industrial-grade automation hardware, Beckhoff PLC, real analogue sensors, and safety-certified wiring to mimic how such systems are designed in real-world engineering. Light is measured by four fast, linear photodiodes not the slower, less accurate LDRs often used in student projects. The PLC compares these readings in real time, calculates the error and with the help of this error, it detects the side at which the panel is misaligned, and moves it using the relays which in turn activates the actuators, respecting mechanical limits and safety rules. The emergency stop, manual override, and automatic reset logic ensure the system respects all safety conditions. Although, the cloudy weather prevented full testing of the system, efforts were made to make sure every component, sensors, actuators, safety switches, and control logic were thoroughly verified physically and by using live monitoring in the TwinCAT software watch-table. The system responded correctly to simulated light changes, frequent little movements were avoided, thanks to the “deadband” and the scaled sensor signals to avoid errors in bright conditions. Beside tracking the sun, this project demonstrates how industrial automation principles, safety systems, signal conditioning, and real-time monitoring can be applied to renewable energy systems. This project is not just a working prototype; it’s a teaching tool that could serve as classroom theory as well as laboratory practical lessons. The result is a robust, reliable and safe solar tracking system. Keywords: EtherCAT, TwinCAT, LM324N Op-Amps, transimpedance amplifier