Automation has encompassed many industries and is necessary for manufacturing to survive. It involves delegating human control functions to equipment to increase productivity, quality and safety while reducing costs. The history of automation progressed from manual control to pneumatic control, hard-wired logic, electronic control using logic gates, and now modern programmable logic controllers which use software programming instead of physical wiring. PLCs offer advantages like reduced space, easier maintenance and flexibility. Industrial automation requires sensors, control hardware, software and networking of controllers.