Sensor: - A sensor is an element in a measurements system that acquires a physical parameter and changes it into electrical signal. E.g. Bellows, Thermocouple
Signal Conditioners:- The signal conditioner performs isolation, impedance matching, noise reduction, amplification, conversion of sensor output signal.
Actuators:- Actuators are the process of conversion of energy to mechanical form.
Controllers:- Controllers are the brains of control system operation and decide the kind of action taken in response to an error