Differences between a Sensor and an Actuator

Figure 1: Actuators of different models.

A sensor is a detection device that can sense the measured information, and can transform the sensed information into electrical signals or other required forms of information output according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control.
An actuator converts the control signal into a physical action or motion (such as opening or closing the valves).
They both work in an industrial environment. Sensors are responsible for monitoring the operation of equipment, while actuators are responsible for driving things within the equipment. The two interact frequently and are two distinct components.
The followings are 7 main differences between the two.

1. Signal Tracking

Sensors and actuators track different signals and operate differently. They have to work together to get the job done. They are physically located in different areas and are often used in separate applications. Sensors are responsible for tracking signals entering the machine, while actuators perform actions after receiving signals.

2. Input and Output

Sensors check for inputs from the environment that trigger specific actions. On the other hand, actuators track the output of the system and the machine.

3. Electronic Signal

Sensors read specific environmental condition information through electronic signals and perform assigned tasks. However, the actuator measures heat or kinetic energy to determine the effect produced.

4. Interdependence

The sensor and the actuator cannot replace each other. In fact, they depend on each other to complete their own certain tasks. The breakdown of either of them makes the whole system down.

Figure 2: IME18 Proximity Sensor.

5. Signal Conversion

The sensor tends to converse physical properties into electric signal, while the actuator transforms the electric signal into physical actions.

6. Location

If there are both a sensor and an actuator, the former is at the input port and the latter is at the output port.

7. Application

Sensors are often used to measure temperature, vibration, pressure or liquid level. Industrial applications of actuators include operating dampers, valves and couplings.

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