Process control
Today automation usually refers to feedback control. An example is cruise control on a car, which applies continuous correction when a sensor on the controlled variable (Speed in this example) deviates from a set-point and can respond in a corrective manner to hold the setting. Process control is the usual form of automation that allows industrial operations like oil refineries, steam plants generating electricity or paper mills to be run with a minimum of manpower, usually from a number of control rooms.