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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.
A manual flight control system uses a collection of mechanical parts such as pushrods, tension cables, pulleys, counterweights, and sometimes chains to transmit the forces applied to the cockpit controls directly to the control surfaces. Turnbuckles are often used to adjust control cable tension.
The system diagram for representing control loops is a Piping and instrumentation diagram. Commonly used control systems include programmable logic controller (PLC), Distributed Control System (DCS) or SCADA. Example of level control system of a continuous stirred-tank reactor. The flow control into the tank would be cascaded off the level control.
The control system performance can be improved by combining the feedback (or closed-loop) control of a PID controller with feed-forward (or open-loop) control. Knowledge about the system (such as the desired acceleration and inertia) can be fed forward and combined with the PID output to improve the overall system performance.
An industrial control system (ICS) is an electronic control system and associated instrumentation used for industrial process control.Control systems can range in size from a few modular panel-mounted controllers to large interconnected and interactive distributed control systems (DCSs) with many thousands of field connections.
The definition of a closed loop control system according to the British Standards Institution is "a control system possessing monitoring feedback, the deviation signal formed as a result of this feedback being used to control the action of a final control element in such a way as to tend to reduce the deviation to zero." [4]
The Airbus A320 family was the first airliner to feature a full glass cockpit and digital fly-by-wire flight control system. The only analogue instruments were the radio magnetic indicator, brake pressure indicator, standby altimeter and artificial horizon, the latter two being replaced by a digital integrated standby instrument system in later production models.
A control system which has only feed-forward behavior responds to its control signal in a pre-defined way without responding to the way the system reacts; it is in contrast with a system that also has feedback, which adjusts the input to take account of how it affects the system, and how the system itself may vary unpredictably.