A programmable logic controller (PLC), is a digital computer used for automation of industrial process, such as control of machinery on factory assembly lines.
The PLCs are widely used in indutrial automation.
The PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed or non volatile memory. A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result.