Programmable Logic Controllers (PLC)

A programmable logic controller (PLC) is a microprocessor based device used for

automation processes, such as control of machinery on factory assembly line, or control of

boxing machines and conveyor lines. A key feature of a PLC is the facility for input/output

(I/O) which connect to sensors and actuators. Through these I/Os, a PLC can read limit

switches, analog process variables (such as temperature and pressure), and the positions

of complex positioning systems. A PLC can operate electric motors, magnetic relays or

solenoids, pneumatic or hydraulic cylinders or analog outputs.

They are one of the most versatile and common device used for industrial automation.

They monitor the inputs, solve logic of a user program and control the outputs.