What is a PLC and what are its main components?

A PLC (Programmable Logic Controller) is an industrial digital computer designed for automation control. Main components include: CPU (executes program logic), Input modules (receive signals from field devices - switches, sensors), Output modules (send signals to actuators - motors, valves), Power supply, Memory (program and data storage), and Communication interfaces. PLCs are rugged, reliable, and designed for harsh industrial environments with real-time control capability.