Actuators and sensors in control technology
Whether it's the automatic shop door or the motion detector in front of the house - sensors and actuators are used here. But what are the control engineering principles behind it?
Sensors - origin of the term and principle
You have probably heard the term sensor often in everyday life. It falls in connection with automatic processes such as the motion detector. The term sensor comes from the Latin word “sentire”, which means “to feel” or “to feel” in German.
- With the help of this origin of the term, the main task of a sensor can be guessed. This consists of measuring physical or chemical parameters (brightness, pressure, temperature, etc.) in its environment and later converting them into an electrical signal.
- Once a sensor has measured such a physical quantity, it converts this result into an electrical signal that can then be processed further.
- What this processing looks like depends on the electronic circuit in which the sensor is involved as a component. For example, it can cause the light to switch on when the sensor in the motion detector detects movement.
- A sensor of this type can be compared to a switch: With a conventional light switch, a circuit is closed when it is actuated, so that a bulb starts to light up. In the case of the motion detector, the sensor represents the switch accordingly. If the sensor measures a movement, a circuit closes and the bulb lights up.
As the name suggests, the component detects the approach of parts via induction. …
Actuator as an opponent to the sensor
If a sensor has generated an electrical signal based on a measurement, an actuator processes this further.
- An actuator is a component that can convert electrical signals into a physical quantity. This not only includes the mechanical movement as with an automatic door, the temperature or the brightness are also possible physical quantities.
- Actors are also called effectors. So you are a component that can achieve an effect. In this case, the effect is the physical quantity, such as movement or temperature change.
In systems that regulate the temperature of rooms or objects, an actuator increases or decreases the temperature of radiators.
The demarcation of actuators and sensors
Actuators and sensors can be clearly distinguished from one another. For a better understanding, you can think of sensors and actuators as sources and sinks of information.
- The sensor measures a certain physical quantity and converts it into an electrical signal. In a figurative sense, the signal is a type of information that an actuator then interprets.
- As part of a room heating system, sensors generate various electrical signals. These depend on whether the temperature is just too low, too high or just right. An actuator can interpret such information and thus carry out the correct action.
- The two components are therefore to be understood as counterparts. The sensor generates an electrical signal from a physical quantity, while the actuator generates a physical quantity from the electrical signal.
- So that communication between the actuators and sensors takes place, they are connected to one another in bus systems. This means that all components are connected to one another and exchange signals.
- In simplified terms, a bus system can also be understood as a group of people in a room who talk to one another. People who are not in the same room cannot participate in the conversation.
Everyday areas of application for actuators and sensors
Now that you know the principle according to which actuators and sensors work, you can already enumerate a few everyday applications.
- There are sensors and actuators in almost every automatic process. These are, for example, mechanisms on the house that lower the shutters when it gets dark outside. Here an outside sensor measures the brightness and an actuator sets the roller shutters in motion when a corresponding signal is received.
- Heaters are also involved in such a circuit. If the outside temperature is too high, radiators do not produce any heat. Here a sensor constantly measures the outside temperature. If the actuator receives a correspondingly low value, the radiator produces heat.
Sensors are the components that generate an electrical signal from a physical quantity. This electrical signal is processed further by an actuator, which uses it to generate a different physical variable. The field of application of the two components extends from everyday objects to special purposes in the industrial sector. Since not every sensor can measure the same thing, it is worth visiting Berker for her. There are informative and revealing functional descriptions for the sensors and actuators offered.
