What is a radio frequency sensor?

　　Radio frequency sensor is a general term for sensors that replace contact detection methods such as limit switches and perform detection without touching the detection object. The movement information and existence information of the detected object are converted into electrical signals. The detection methods that are converted to electrical signals include the method of using eddy currents generated in the metal body of the detection target caused by electromagnetic induction, the method of capturing the change in the capacity of the electrical signal caused by the proximity of the sensing body, the method of sharp stone and the guide switch. .

　　The radio frequency sensor is a device with the ability to perceive the proximity of an object. It uses the sensitive characteristic of the displacement sensor to recognize the proximity of the object and outputs the corresponding switch signal. Therefore, the radio frequency sensor is usually called a proximity switch.

　　[1] It is a general term for sensors that replace contact detection methods such as switches and do not need to touch the detected object. It can detect the movement and existence of the object and convert it into an electrical signal.

　　[2] In the JIS standard, based on the IEC60947-5-2 non-contact position detection switch, the JIS standard (JIS C 8201-5-2 low-voltage switchgear and control device, 5th control circuit device and switch element was established , Section 2 proximity switch). In the definition of JIS, products that can detect the proximity of objects and the presence of nearby objects in a non-contact manner in the sensor are collectively referred to as "proximity switches". They are composed of induction type, electrostatic capacitance type, ultrasonic type, photoelectric type, and magnetic force. Type and other composition. In this technical guide, the inductive radio frequency sensor that detects the presence of metal, the electrostatic capacitance radio frequency sensor that detects the presence of metal and non-metal objects, and the switch that uses the DC magnetic field generated by magnetic force are defined as "radio frequency sensors."

　　The detection principle of inductive radio frequency sensor

　　Through the influence of the external magnetic field, the magnetic loss caused by the eddy current generated on the surface of the conductor is detected. A method in which an AC magnetic field is generated in the detection coil, and the impedance change caused by the eddy current generated by the metal body of the detection body is detected.

　　In addition, as another method, it also includes an aluminum detection sensor that detects frequency and phase components, and an all-metal sensor that detects only the impedance change component through a working coil.

　　On the surface of the detection body and the sensor, the state of the transformer occurs.

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