Programmable logic controller is a digital computer used for the automation of various electro-mechanical processes in industries. These controllers are specially designed to survive in harsh situations and shielded from heat, cold, dust, and moisture etc. The hardware components of a PLC system are CPU, Memory, Input/Output, Power supply unit, and programming device. PLC consists of a microprocessor which is programmed using the computer language. A visual programming language known as the Ladder Logic was created to program the PLC. The program is written on a computer and is downloaded to the PLC via cable. These loaded programs are stored in non – volatile memory of the PLC.