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Device with the ability to sense object proximity

Device with the ability to sense object proximity

Jul 24, 2019

The proximity sensor is a general term for sensors that do not require contact with a detection object for detection, instead of a contact detection method such as a limit switch. The movement information and the presence information of the detectable object are converted into electrical signals. In the detection method for the electric signal, the method of detecting the eddy current generated in the metal body to be detected by the electromagnetic induction, the method of changing the capacity of the electric signal caused by the approach of the sample, and the manner of the guide and the switch are included. .

A proximity sensor is a device that has the ability to sense the proximity of an object. It uses a displacement sensor to have a sensitive characteristic to an approaching object to recognize the proximity of the object and output a corresponding switching signal. Therefore, the proximity sensor is usually referred to as a proximity switch. It is a general term for a contact detection type detection method such as a switch, which is used for the purpose of not contacting the object to be detected, and can detect the movement and presence information of the object and convert it into an electrical signal.

In the JIS standard, the JIS standard (JIS C 8201-5-2 low-voltage switchgear and control device, fifth control circuit device and switching device, and 2nd) are established according to the non-contact position detecting switch of IEC60947-5-2. Section proximity switch). In the definition of JIS, products that can detect the proximity of an object and the presence or absence of a nearby detection object in a non-contact manner are collectively referred to as "proximity switches", which are inductive type, electrostatic capacity type, ultrasonic type, photoelectric type, magnetic force. Type and other components. In this technical guide, an inductive proximity sensor that detects the presence of metal, a capacitance type proximity sensor that detects the presence of metal and non-metallic objects, and a switch that uses a magnetic field generated by a magnetic field are defined as "proximity sensors."

Detection principle of inductive proximity sensor

The magnetic loss caused by the eddy current generated on the surface of the conductor is detected by the influence of an external magnetic field. A method of detecting an impedance change caused by an eddy current generated by a metal body of the body by detecting an alternating magnetic field in the detecting coil.

Further, as another method, an aluminum detecting sensor that detects a frequency phase component and an all-metal sensor that detects only an impedance change component through the working coil are further included.

The state of the transformer occurs on the surface of the detector side and the sensor side.