page_title: Control system
section_title: Feedback control systems
hierarchical_section_title: Control system / Feedback control systems
caption_attribution_description: English: Example of a single industrial control loop; showing continuously modulated control of process flow.
context_page_description: 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.
  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 being controlled with the desired value or setpoint, and applies the difference as a control signal to bring the process variable output of the plant to the same value as the setpoint.
  For sequential and combinational logic, software logic, such as in a programmable logic controller, is used.
context_section_description: In the case of linear feedback systems, a control loop including sensors, control algorithms, and actuators is arranged in an attempt to regulate a variable at a setpoint (SP).  An everyday example is the cruise control on a road vehicle; where external influences such as hills would cause speed changes, and the driver has the ability to alter the desired set speed. The PID algorithm in the controller restores the actual speed to the desired speed in the optimum way, with minimal delay or overshoot, by controlling the power output of the vehicle's engine.
  Control systems that include some sensing of the results they are trying to achieve are making use of feedback and can adapt to varying circumstances to some extent. Open-loop control systems do not make use of feedback, and run only in pre-arranged ways.
caption: Example of a single industrial control loop; showing continuously modulated control of process flow.
exif: {}