Monitoring Systems
Monitoring systems seek to observe and record data about an environment through sensors. They check new data against stored values and, if the new data is outside an acceptable range, a warning message is sent – but the system does nothing further to effect the change (e.g. recording the temperature of a greenhouse).
Examples: heart rate monitoring systems, monitoring intruders in a burglar alarm system, checking engine temperature, monitoring pollution levels in a river.
Control Systems
A control system is a set of hardware and software used to regulate the operation of a system, such that if new data is outside an acceptable range the output affects the next set of inputs. Control systems actively maintain or change the state of a system through the use of actuators. There are two basic types:
- Dedicated control systems: basic systems that carry out a pre-programmed set of instructions, e.g. a traffic light system that changes at fixed time intervals.
- Computer-controlled systems: use a computer connected to a sensor to control the output device, making the system more flexible.
Examples: turning street lights on/off, regulating a central heating/air conditioning system, operating anti-lock brakes, regulating a greenhouse environment. A related type is the Numeric Control System (NC), which automates machine tools operated by programmed commands rather than manually via hand wheels or levers.
Difference Between Monitoring and Control Systems
| Monitoring system | Control system |
|---|---|
| Seeks to observe and record data about an environment through sensors | Seeks to actively maintain or change the state of a system through the use of actuators |
| Sends a warning (screen, alarm) if new data is outside acceptable range | Sends signals to control valves, motors, etc. if new data is outside acceptable range |
