In order to achieve long-distance measurement, a bridge differential inductance detection circuit is employed; on this basis, an automatic zero adjustment technique for sensors using an integral–proportional-integral controller is proposed in this work to achieve consistent product production and efficient installation and debugging, and the mathematical model of the bridge differential inductance detection circuit is established to effectively design the controller parameters. Furthermore, an implementation method for an inductive proximity sensor with an attenuation coefficient of 1 is also proposed based on the bridge differential inductance detection circuit by querying the proximity distance table in the field-programmable gate array (FPGA) to detect multiple target metal objects at the same inductive distance. Simulation and experimental results show that the proposed method is correct and effective.

https://www.mdpi.com/1996-1073/13/24/6482/pdf

An Implementation Method for an Inductive Proximity Sensor with an Attenuation Coefficient of 1

A double-coil inductive displacement transducer is a non-contact element for measuring displacement and is widely used in large power equipment systems such as construction machinery and agricultural machinery equipment. The type of coil excitation signal has an impact on the performance of the transducer, but there is little research on this. Therefore, the influence of the coil excitation signal on transducer performance is investigated. The working principle and characteristics of the double-coil inductive displacement transducer are analyzed, and the circuit simulation model of the transducer is established. From the aspects of phase shift, linearity, and sensitivity, the effects of a sine signal, a triangle signal, and a pulse signal on the transducer are compared and analyzed. The results show that the average phase shift, linearity, and sensitivity of the sine signal were 11.53°, 1.61%, and 0.372 V/mm, respectively; the average phase shift, linearity and sensitivity of the triangular signal were 1.38°, 1.56%, and 0.300 V/mm, respectively; and the average phase shift, linearity, and sensitivity of the pulse signal were 0.73°, 1.95%, and 0.621 V/mm, respectively. It can be seen that the phase shift of a triangle signal and a pulse signal is smaller than that of a sine signal, which can result in better signal phase-locked processing. The linearity of the triangle signal is better than the sine signal, and the sensitivity of the pulse signal is better than that of the sine signal.

/pdf/effect-of-excitation-signal-on-double-coil-inductive-2xd3duv6.pdf

Effect of Excitation Signal on Double-Coil Inductive Displacement Transducer

Inductive proximity sensor has the advantages of high sensitivity, good stability and high reliability. According to the principle of electromagnetic induction, it converts the distance signal of the target metal into electrical signal so as to control the mechanical system. In order to obtain high precision of distance measurement, a closed-loop control circuit is designed to realize the bias inductance. The mathematical model of the bridge differential inductance detection circuit is established and the transfer function from the control to the bias inductance is derived. On this basis, an I-PI controller is proposed, the method of automatic zero calibration of inductive proximity sensor is realized and the control parameters of the controller are given, which is helpful to obtain the consistent high reliability of the product. Finally, simulation results verify the correctness of the mathematical model and control strategy.

Realization of Automatic Zero Calibration of Inductive Proximity Sensor Based on Inductive Increment Detection

A modern approach to active learning is a technique called “learning by doing”. It is usually the most wanted approach. As an example of this technique, this paper presents a student learning process about sensors and their properties by performing experiments and learning from sensors’ manuals. In order to compare distance sensors in industry applications, an experiment was conducted. Experimental results leads to conclusion which of the available sensors showed the most accurate results in relation to the results given by the manufacturer. Finally, conclusions have been made about reasons for the deviation of individual sensors from the predicted values.

Xia Xiaonan

Papers

An Implementation Method for an Inductive Proximity Sensor with an Attenuation Coefficient of 1

Realization of Automatic Zero Calibration of Inductive Proximity Sensor Based on Inductive Increment Detection