How control and monitoring has be done
- Sensors gather information from application being monitored or controlled.
- The data being gathered is frequently analogue in nature and hence requires translating into digital using an analogue to digital converter (ADC) to enable the computer or microprocessor to 'understand' and process the data from the sensors.
- Computer or microprocessor will compare the incoming data with the data values stored in memory
- if monitoring, computer/microprocessor system will warn the user in the form of a sound (for example a siren if a burglar alarm, a loud beeping sound if monitoring patients in a hospital) and/or read outs (for example heart rate trace in hospital monitoring system, temperature reading on a chemical plant).
- If a control system, computer would send a signal to a device that will be converted to analogue using a DAC (analogue to digital converter); actuators are generally used to operate devices such as valves, heaters etc.
- The device will be instructed to switch off or on (for example if controlling a central heating system, if temperature > set temperature a heater would be switched off and/or a cooling fan switched on; if temperature is below the set point then heating would be switched on and/or a cooling fan switched off)
- Microprocessor/computer system will continually monitor the data coming from sensors.