What Is an Inductive Sensor?

An inductive sensor is a device that utilizes changes in the coil's self-inductance or mutual inductance to achieve non-electrical electrical measurement. With inductive sensors, parameters such as displacement, pressure, vibration, strain, and flow can be measured. It has a series of advantages such as simple structure, high sensitivity, large output power, small output impedance, strong anti-interference ability and high measurement accuracy, so it is widely used in electromechanical control systems. Its main disadvantage is the slow response, which is not suitable for fast dynamic measurement, and the resolution of the sensor is related to the measurement range. The measurement range is large, the resolution is low, and vice versa. ^[1]

Inductive

Inductive

Inductive sensors are divided into 3 types: self-inductive sensors that change the air gap thickness , that is, variable gap inductive sensing; self-inductive sensors that change the air gap section S, that is, variable cross-section inductive sensors; and that the air gap thickness is also changed And air-gap section S, which is a solenoid-type inductive sensor.

As a tool for collecting and acquiring information, sensors play an important role in the automatic detection and quality monitoring of the system. Inductive sensor is a mutual inductance type inductive sensor. It can transfer small mechanical quantities such as displacement, vibration, pressure-induced length, inner diameter, outer diameter, non-parallelism, non-verticality, eccentricity, ellipticity and other non-electrical physical quantities. The geometric change of the sensor is converted into a small change of the electrical signal and converted into an electrical parameter for measurement. It is a highly sensitive sensor with a simple and reliable structure, large output power, strong resistance to impedance, low requirements for the working environment, and stability. Good and a series of advantages, so it is widely used in various engineering physical quantity detection and automatic control systems ^[3]

Inductive

(1) Scheme selection Before selecting a scheme, the given technical indicators should be clarified first, such as the indicated value range, indicated value error, resolution, repeatability error, time drift, temperature drift, use environment, etc.
(2) Selection of core material The main basis for core material selection is to have a high magnetic permeability, a high saturation magnetic induction intensity, a small hysteresis loss, and a small remanence and coercivity. In addition, large resistivity, high Curie point temperature, stable magnetic properties, and easy processing are also required. Commonly used magnetic materials are ferrite, iron-nickel alloy, silicon steel sheet and pure iron.
(3)

1. Attenuation of detection distance. The glide is iron, which is suitable for the detection of inductive sensors. The size of the measured part of glide is slightly smaller than the size of the standard test object (the size of the standard test object is 3 times the rated detection distance. In this application, the standard size should be 120 * 120mm ), Then there will be a certain attenuation.
2. On-site anti-interference ability. This is a problem that cannot be ignored. Ordinary inductive sensors are easily interfered by motors or inverters. Many technicians only choose corresponding strong anti-electromagnetic interference sensors for applications in the vicinity. However, in the automobile manufacturing workshop, the factory building is large, and field technicians are accustomed to using walkie-talkies to communicate, especially when they walk on the walkie-talkie, they will inadvertently approach the sensor, which will cause short-term failure.
3. Installation. With the popularization of inductive sensors, the sensors have not only improved in electrical performance, but also their mechanical design has become more and more user-friendly. To the greatest extent possible to achieve user-friendly installation. Reduce the stocking of multiple similar products and reduce installation and maintenance time.
4. Guarantee of stable operation. In the use of depots, it is necessary to eliminate any oil and dust pollution. In addition, when the glide passes through the track, the vibration is long-lasting, and the excellent vibration resistance also plays a very important role ^[6] .