5. Process

Once the input data from the sensors has been received by the computer, it can then begin to process it. The data will be compared against a set of rules which have been programmed into the control system and a decision will be made. For example, think about a central heating system:

The system is set to keep the room at a constant 22 degrees C. 

1. The sensor will take regular temperature readings in the room and send the readings back to the computer. 
2. The computer will then process the data to see if it matches the ideal 22 degrees C. 
3. If it is lower e.g. 20 degrees C, then the computer will need to identify the correct response (e.g. the heating must be turned on). 
4. If it is equal or above 22 degrees C then the computer must identify the correct response (e.g. the heating must be turned off).

This stage is called processing.  The computer can only follow the rules that it has programmed into the control system, it cannot make its own decisions.