Inductive Sensor Measurement Circuit Design And Improvement

Inductive displacement sensor, with a virtually infinite resolution, highreliability and extremely long life, has been applied to the measurement of micro-displacement for a long experience. The product made abroad has very high accuracy and reliability due to the ripe technology, but it is very expensive as well. There are some defects in domestic sensor such as high temperature drift, low reliability, small measuring range etc. Against these defects, this paper proposes a series of improvements on the measuring circuit of inductive displacement sensor, adapting it to the development of ultra-precise technology. On the basis of accuracy analysis, some techniques are combined to improve the measuring precision on the sine wave generating circuit, AC signal amplifying circuit, band-pass filtering circuit, phase sensitive detection circuit, data acquisition circuit and so on. Many changes have been made about the layout and wiring of circuit board, the choice of circuit and components, the assembly and debugging of circuit and so on. The data processing software further improves the precision. By a series of testing experiments, the static performance of the sensor is obtained. The experimental results indicate that if the temperature is normally constant, the sensor will be very stable. Under the measurement range of -20μm to +20μm, the drift is 10nm/20minute; sensitivity is 281Mv/μm; resolution is higher than 10nm; repeatability is 0. 12% F. S; linearity is 0.2% F. S. The improvements on the sensor have laid the foundation for its further unification, instrumentalization and commercialization .