What is an automated system?
An automated system carries out a task with little or no human input. It repeatedly measures its surroundings, decides what to do and then acts, all by itself.
The three main parts
- Sensors measure a physical quantity, such as temperature, light, pressure or movement, and send the reading as data to the processor.
- A microprocessor compares each reading with pre-set values (stored settings) and decides what action is needed.
- Actuators are output devices, such as motors, heaters, pumps or valves, that carry out the physical action.
Key idea
The basic loop is sensor -> microprocessor -> actuator. The sensor gives data, the microprocessor makes the decision, the actuator performs the action, and the cycle repeats continuously.
Why use automated systems?
They can work continuously without tiring, respond faster than a human, and give consistent, accurate results. They are useful in dangerous places, such as chemical plants, and for tasks that must be repeated exactly, such as in a factory. A drawback is that they are expensive to set up and may fail if a sensor gives a wrong reading.
Example
In a greenhouse, a temperature sensor sends readings to a microprocessor. If the temperature falls below the set value, the microprocessor switches on a heater (the actuator). When the temperature rises above the set value, the heater is turned off.