Realization Of Inductive Proximity Switch With High Reliability

Since entering the 21st century,proximity switches have been more and more widely used in various fields,but the demand for proximity switches in each field is also different,so there are many different kinds of proximity switches.With the characteristics of good stability and strong anti-interference ability,inductive proximity switch is more suitable for complex environment than other types of proximity switches.Therefore,inductive proximity switch is also more and more widely used.With the continuous development of industry and aerospace technology,more stringent indicators are put forward for inductive proximity switch,which not only requires simpler structure and higher integration,but also requires longer response action distance and higher detection distance accuracy in performance,but also can work reliably for a long time in a wide temperature range.Therefore,the research on the high reliability inductive proximity switch working stably for a long time in a wide temperature range has important practical significance.This paper studies the implementation method of high reliability inductive proximity switch.In order to achieve high reliability,the proximity switch integrates the oscillation circuit and the comparison circuit.The inductance in the frequency selection circuit in the oscillation circuit adopts tank magnetic core and coil,which not only achieves the inductance value required for long-distance measurement and oscillation frequency,but also shields the interference of external magnetic field and improves the measurement accuracy of inductive proximity switch.This thesis studies the implementation method of high reliability inductive proximity switch.In order to achieve high reliability,the proximity switch integrates the oscillation circuit and the comparison circuit.The measurement accuracy of the magnetic field and the external inductance in the circuit can be improved by using the selected magnetic core,which is close to the required frequency of the magnetic field and the external inductance in the circuit at the same time.This thesis studies the long-time stable operation of inductive proximity switch under wide temperature.The components of inductive proximity switch are thermally designed to ensure that all components can work normally in the working temperature range.In a wide temperature range,the influence of temperature on inductive proximity switch is shown as the influence on the amplitude of oscillation circuit.Therefore,a series parallel network of thermistors is designed to compensate the proximity switch,so that the amplitude of the oscillation circuit is constant in a wide temperature range,so as to realize the wide temperature range measurement of the inductive proximity switch.For the realization of high reliability inductive proximity switch,the working principle of each module is studied,including oscillation circuit,comparison circuit,thermistor series parallel network circuit and output circuit.On this basis,the circuit of high reliability inductive proximity switch is designed.In the oscillation circuit of inductive proximity switch,the amplification circuit with large gain is selected to realize long-distance measurement.The large coil of frequency selection circuit in the oscillation circuit is used not only as the transmitter of electromagnetic field measurement,but also as the receiver of distance measurement information;The small coil of frequency selection circuit in oscillation circuit is helpful to realize long-distance measurement;The output of the proximity switch is controlled by comparing the received signal of the oscillation circuit with the reference voltage.The high and low levels of the output circuit represent the response of the approach distance of the target object.When the metal plate approaches,the inductance of the large coil decreases under the influence of electromagnetic induction,resulting in the stop of the oscillation circuit,so that the output signal of the proximity switch changes from 1 to 0,that is,the jump of the switch is realized;According to the requirements of reliability index,the reliability of inductive proximity switch is predicted and designed,which can be used as the basis of device selection.In this thesis,the performance of high reliability inductive proximity switch is simulated and verified by candence and Multisim.On this basis,the prototype of high reliability inductive proximity switch is made and tested.The reliability of 25 prototypes is tested for 10 days.The experimental and test results verify the correctness of the design method of inductive proximity switch in this paper.