8. Feedback System

Most control systems carry on working continuously, they don’t just stop after one decision has been made.

Take the example of the central heating system previously.

1. The sensor takes a reading of 20 degrees and sends it to the computer.  The computer processes this and sends a signal to the central heating to switch on.
2. The sensor takes a reading of 21 degrees and sends it to the computer.  The computer processes this and sends a signal to the central heating to remain switched on.
3. The sensor takes a reading of 22 degrees and sends it to the computer.  The computer processes this and sends a signal to the central heating to switch off.
4. The sensor takes a reading of 21 degrees and sends it to the computer.  The computer processes this and sends a signal to the central heating to remain switched on.

This cycle of taking one reading and responding to it, then taking another reading and responding to it is known as ‘Feedback’.

Definition: Feedback is where the output of a system affects the input.