Proximity sensor working principle

- Oct 12, 2019-

Proximity sensors, also known as non-contact proximity sensors, are ideal electronic switching sensors. When the metal detector is close to the sensing area of the sensor, the switch can be contactless, without pressure, without spark, and quickly emit electrical commands, accurately reflecting the position and stroke of the moving mechanism, even for general stroke control, its positioning accuracy, operation Frequency, service life, ease of installation adjustment, and ability to withstand harsh environments are not comparable to typical mechanical travel switches. It is widely used in machine tools, metallurgy, chemical, textile and printing industries. It can be used as limit, counting, positioning control and automatic protection in the automatic control system. Proximity sensors have long service life, reliable operation, high repeatability, no mechanical wear, no spark, no noise, strong anti-vibration ability. So far, the application range of proximity sensors has become more and more extensive, and the speed of its own development and innovation is extremely rapid.


Proximity sensor A position switch that can be operated without mechanical direct contact with moving parts. When the object approaches the sensing surface of the switch to the working distance, the switch can be operated without mechanical contact and any pressure is applied to drive the DC device or Provide control instructions to the computer (plc) device. The proximity switch is a switch type sensor (ie, non-contact switch). It has the characteristics of the stroke switch and the micro switch, and has sensing performance, reliable operation, stable performance, fast frequency response, long application life and anti-interference. It has strong capabilities, such as waterproof, shockproof and corrosion resistant. Products are inductive, capacitive, Hall, AC, DC.



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working principle:


The basic working principle of the proximity sensor is to pass the light from the light source to the modulator, and the parameters to be measured interact with the light entering the modulation area, resulting in the optical properties of the light (such as the intensity, wavelength, frequency, phase of the light, The polarization state, etc., changes, called the modulated signal light, and the effect is measured on the transmission characteristics of the light to complete the detection.


(1) Functional type - made with a sensitive property or function close to itself


(2) Light-transmitting type - close to just transmitting light, it adds other sensitive components near the end face or in the middle to feel the measured change.


Among the various types of switches, there is a displacement sensor that is "perceived" to its object. Using the displacement sensor's sensitive characteristics to the approaching object achieves the purpose of controlling the switch to open or close, which is the proximity switch.


When an object moves toward the proximity switch and approaches a certain distance, the displacement sensor will "perceive" and the switch will act. This distance is usually called the "detection distance". However, the detection distances of different proximity switches are also different.


Sometimes the objects being inspected are moved to the proximity switches one by one at a certain time interval, and are separated one by one, so that they are repeated continuously. Different proximity switches have different responsiveness to the detected object. This response characteristic is called the "response frequency."