Inductive sensor

About: Inductive sensor is a research topic. Over the lifetime, 2282 publications have been published within this topic receiving 21984 citations.

A simple signal conditioning scheme for inductive sensors

Abstract: Signal conditioning of inductive sensors so as to obtain an output proportional to just the change in the inductance alone is fraught with problems. The large value of self inductance that is present in a sensor coil and the change in the inductance being a small fraction of this large inductance coupled with the winding resistance of the sensor coil make signal conditioning of such inductive sensors a challenge. This paper presents a simple analog front-end suitable for signal conditioning of inductive sensors. The proposed signal conditioning circuit provides an output linearly related to the change in inductance due to the measurand alone, masking the large value of self (offset) inductance present in inductive sensors as well as the appreciable winding resistance. A prototype of the proposed signal conditioning circuit was developed and tested in the laboratory. Test results validate the efficacy of the technique presented herein.

Comparative study of alternative circuit configurations for inductive sensors

Abstract: We study three different electronic circuit configurations for the excitation, recovering and analysis of the response of magnetic sensors based on inductive changes. The best characteristics are sought: maximum output, stability, linearity and large sensibility together with an economic design. To simulate the sensible element, we use a general coil with mobile magnetic core that resembles any real case where variations of induction take place. Three parts are readily distinguished in the circuits: oscillator, filter and rectifier. In one of the tested configurations the variable inductance is part of the oscillator, whereas in the other two, it is used in the filter. In turn, two different types of common oscillators are investigated: Colpitts and Wien bridge. The best option turns out to be the one composed by a Wien bridge oscillator with the variable inductance in the filter.

Inductive proximity sensor

Abstract: PURPOSE: To prevent an inaccurate sensing result from being made due to inter nal loss of a resonance circuit. CONSTITUTION: An inductive proximity sensor includes a power supply and a coil 2. The power supply supplies a periodic current to the coil 2, and its conduction time interval is shorter than a feeding time interval. A response of an object to be detected is measured at a time interval, when the current flowing to the coil 2 is essentially zero. COPYRIGHT: (C)1992,JPO

Influence of External Conductive Objects on the Performance of an Ironless Inductive Position Sensor

Abstract: The ironless inductive position sensor (I2PS) is a novel device that measures high-precision linear position without being affected by radiation and external magnetic fields Built on the basis of the linear variable differential transformer, the I2PS senses the variation of flux linkage between the supply and sense coils which is related to the linear position of the moving coil This paper characterizes the magnetic performance of the I2PS through a detailed analysis of the impact of axisymmetrical external conductive objects on the sensor This characterization is performed through a set of finite element simulations and through dedicated experiments Axisymmetrical conductive objects result in offset voltages, but the differential measurement techniques combined with high-resolution calibration curves mitigate this effect

Detection of foreign particles in lubrication oil with a microfluidic chip

Abstract: Purpose The purpose of this paper is to help understand the mathematical model of inductive sensor and to improve the sensitivity of nonferrous metal particle detection. Design/methodology/approach The expression of impedance change is established, while the distribution regularities of the magnetic field inside and outside the metal particle are obtained based on the Maxwell equations in complex forms, the analytic solution of the electromagnetic field is obtained and the experiment validation is implemented. Findings The expression of impedance and the analytic solution of the electromagnetic field are obtained. It is shown that the inductance change is more obvious than resistance change for the iron particles, but for copper particles, resistance change is more obvious and the resistance change increases with the frequency. In this work, copper particles (size: 20 µm) are detected at 2 MHz excitation frequency, and the imaginary part of impedance changes without adding any device, which is provided with a prominent guideline for detection of nonferrous particles of size less than 100 µm. Originality/value The expression of impedance change is established, the analytic solution of the electromagnetic field is obtained and copper particles (size: 20 µm) are detected at 2 MHz excitation frequency, and the imaginary part of impedance change without adding any device, which is provided with a prominent guideline for detection of nonferrous particles of size less than 100 µm.