 A control system manages commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a from a staff controlling a domestic boiler to large industrial control systems which are used for controlling processes or machines. For continuously modulated control, the feedback controller is used to automatically control a process or operation. The control system compares the value or status of the process variable PV being controlled with the desired value or set point ESP and applies the difference as a control signal to bring the process variable output of the plant to the same value as the set point. For sequential and combinational logic, software logic, such as in a programmable logic controller, is used.