What is a capacitive sensor?
A capacitive sensor is an electronic device that can detect solid or liquid targets without physical contact.
To detect these targets, capacitive sensors emit an electric field from the end of the sensor. Any target that can disrupt this electric field can be detected by a capacitive sensor. Types of Capacitive Proximity Sensors Materials Can Detect Some examples of solids that capacitive sensors can detect are metals, plastics, wood, paper, glass, and textiles.
Capacitive sensors can also detect liquids such as water, oil and paint.
Some capacitive proximity sensors can be used to detect materials inside a non-metallic container. The capacitive sensors used to do this have an adjustable range. We will explain how to adjust this type of capacitive sensors with just one example.
The main components of a capacitive sensor
Capacitive proximity sensors have four main parts, the sensor body, the sensor face, the indicator light, and the end of the cable or cable connection.
If the sensor has an adjustable sensor range, it also has an adjusting screw to adjust the sensor range.
1) Sensor body
Inside the sensor body is the location where the circuit causes the sensor to work.
2) Face sensor
The sensor face is the part of the sensor that is used to detect targets.
3) Indicator light
The indicator light on the sensor side is located at the other end of the sensor. This light goes out when the target is within the sensor’s range and when the target is outside the sensor range.
The sensor range of the capacitive sensor is the maximum distance at which the target can be sensed from the sensor face.
If it is at a distance of six millimeters from the sensor surface and the sensor amplitude is twelve millimeters, it would be an example of being within the range of sensors.
You can find the sensor range of the sensors on the sensor data page or you can search for it on the manufacturers website.
4) Sensor connection
These sensors can be purchased through the cable connected to them or they can have a connection to which the cable is screwed.
In this cable you will find four wires. The color of these wires is brown, blue, black.
1) The brown wire is connected to twenty-four volts positive DC.
2) The blue wire is connected to twenty-four volts of negative DC.
3) Black and white wires are the output wires of the sensor. The black wire is the open output wire of the sensor. The sensor sends a signal to the black wire when detecting the target. When the sensor does not detect the target, it stops sending this signal.
4) The white wire is the closed output wire of the sensor. The sensor sends a signal to the white wire when it does not detect the target. By detecting the target, the sensor prevents this signal from being sent.
Capacitive sensor outputs
The output of a capacitive sensor can be a positive signal (or PNP) or a negative signal (or NPN). Depending on how the sensor outputs are connected, it is determined what style of sensor outputs are needed.
If the capacitive sensor has an adjustable measuring range, it has an adjusting screw. Turning the screw clockwise increases the sensitivity of the sensor and turning the screw counterclockwise reduces the sensitivity of the sensor.
Installing a capacitive sensor
Installing a capacitive sensor can be easy, it depends more on how the sensor is used and where it is located. Some styles of capacitive sensors can only be installed in place by screwing them on. Other styles of capacitive sensors can be installed by drilling and tapping a hole the size of a sensor, and sometimes using a bracket to mount the sensor is the best solution.
How to adjust the capacitive sensor
We will now explain how to set up a capacitive sensor to detect water in a non-metallic container. In this example, we will use a drinking glass made of plastic for the container and a capacitive sensor with an adjustable sensor range mounted on a beam to detect water. Place the empty drinking glass next to the sensor, the sensor indicator light comes on. This means that the sensitivity of the sensor is highly adjusted and must be adjusted. To adjust the sensor sensitivity, turn the sensitivity adjusting screw counterclockwise to turn off the indicator light.
Now we fill the glass of water up to the sensor. Notice that the indicator light comes on. If we take some water to the surface below the sensor, the indicator light goes out. This means that the capacitive sensor is set correctly.
Capacitive sensor applications
Capacitive sensors can be used in different ways. They can be used to detect parts in workstations, conveyors and robots.
They can also be used to count and check fluid levels. When these sensors are used to detect a part, the sensor only sends a signal to the workstation, conveyor, or robot to let them know when the part is there. A capacitive sensor can be set on the conveyor to create a counter that can count the number of components made.
Capacitive sensors can also be used to monitor high or low reservoir fluid levels and to alert anyone.
You dear ones, by reading this article, you got more information about capacitive sensors. That they are more likely to detect solid or liquid targets without making physical contact with an electric field. You have learned the four main parts of a capacitive sensor and they have different options to meet the needs of most applications.
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