Programmable Logic Controller (PLC): An Overview
A Programmable Logic Controller (PLC) is an industrial digital computer designed to control and automate machinery and processes in manufacturing plants, utilities, and infrastructure systems. PLCs are widely used because of their reliability, flexibility, and ability to operate in harsh industrial environments such as high temperatures, electrical noise, vibration, and dust.
Working Principle of a PLC
A PLC continuously monitors the status of input devices, executes a user-defined control program, and updates output devices accordingly. Inputs may include sensors, switches, or measurement devices that provide information about machine or process conditions. Outputs typically control actuators such as motors, valves, relays, and indicators. The control logic is executed in a repetitive cycle known as the scan cycle, ensuring real-time and deterministic operation.