Control : Introduction

A computer control system is a computerised system designed to control a process.

Control systems use sensors such as temperature sensors and pressure pads to monitor physical quantities. Using software the control system will carry out actions based on the quantities it has measured. These actions might include turning on devices such as a light or pump or sounding a buzzer.

Control systems can often be found built into other machines. These are known as embedded systems. They are also used by companies to manufacture products using Computer Assisted Manufacturing (CAM) and robots.

Here are some example control systems :

Example Control Systems
Traffic Lights	The computer controls the sequences of lights displayed at a cross-roads to ensure that cars do not crash. Additionally the computer operates a pedestrian crossing to let pedestrians cross the road when a button is pressed.
Simple Greenhouse	The computer controls the temperature in a greenhouse to maintain the conditions required for the plants in it to grow. If the temperature gets too cold then the computer turns on a heater to keep the plants warm.
Robot Arm	The computer controls the movement of a robot arm which sprays parts of a car body. The arm must only spray when the body part is present and must then follow a programmed spraying path. The arm must stop if any foreign object, such as a human being, gets in its way.

GCSE ICT Companion 04 - (C) P Meakin 2004