What is Computer Control?

Computers are used to control many types of devices such as robots. The computers controlling the robots must be programmed with instructions to tell them what to do. The programs are written in computer languages. Logo is one such language.

Equipment and devices are controlled by pressing buttons either on a control panel or on a remote control. Some equipment, like burglar alarms, work when they receive a message from a sensor placed in a room or outside.

Examples of Equipment and Devices which use Computer Control

Everyday devices rely on simple control features to make them operate. Some of these devices rely on a single instruction, for example a barrier in a car park where money or a ticket will make it operate. Other devices rely on a sequence of instructions to operate, for example a pelican crossing where a button activates the lights then the walk signal.

Why use computers to control things?

Computers are used because they:

• never get tired,
• never lose concentration,
• don't make mistakes,
• can repeat the same instructions over and over again in exactly the same way,
• are cheaper to employ than humans.

How does it work?

The CPU

All the systems that use control technology have a CPU, a central processing unit, just like a computer. This is the brains of the equipment. It stores all the information it needs to make the equipment work. Microchips are CPUs.

When a message is sent to a CPU by pressing buttons on a control panel or activating sensors, the CPU responds by looking at what it has stored in its memory so it can follow the instructions.

Procedures

To make things work there must be a procedure. A procedure is a sequence of instructions or commands that a CPU stores. It is important that the procedure is written correctly so that things happen in the correct order.

What is Computer Monitoring?

Computer monitoring involves the use of sensors for two main purposes:

• As a scientific measuring tool to record information about environmental changes over a period of time. The resulting information can be examined in a table or as a graph. This is usually known as data logging.
• To provide feedback for a control system.

Examples of where sensors are used

central heating, security lights, street lights, supermarket freezers.

The environment is monitored constantly to check if changes have occurred, eg when it gets cold the heating comes on, or street lights come on when it gets dark.