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 thermostat controlling a domestic boiler to large
industrial control systems which are used for controlling processes or
machines. The control systems are designed via control engineering process.
For continuously modulated control, a 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 setpoint (SP), and applies the difference as a control signal to
bring the process variable output of the plant to the same value as the
setpoint.