A high-precision resistance signal conditioning circuit and method based on a current source

Abstract

The invention belongs to the field of aero-engine temperature sensor (resistance signal) monitoring. The invention relates to a high-precision resistance signal conditioning circuit and method based on a current source, which solves the problem that the wire resistance and protective circuit impedance superposition of the temperature sensor currently used in the aircraft engine during the signal transmission process affects the temperature acquisition accuracy, and realizes the effect of the temperature acquisition accuracy on the engine. Accurate measurement of working temperature to determine whether the engine is working at normal temperature. It includes a lightning protection circuit, an EMI filter circuit, a Wheatstone bridge, a precision current source, a low-pass filter circuit, a differential amplifier circuit and a second-order low-pass filter circuit; the present invention reduces the temperature sensor (resistance signal) cable resistance caused by the system On the basis of realizing high-precision temperature signal acquisition, the open-circuit detection function of the temperature sensor is realized through a circuit with a simple structure. The circuit has the characteristics of simple structure, strong reliability and high practicability.

Description

technical field [0001] The invention belongs to the field of aero-engine temperature signal monitoring, and relates to a high-precision resistance signal conditioning circuit and method based on a current source, which are used to monitor the temperature sensor ( Resistance signal) high-precision monitoring. Background technique [0002] In each working state of the aircraft, it should be able to reliably and real-time monitor the temperature state of its engine. In actual work, it is necessary to monitor the working temperature of the engine. In a complex environment with strong vibration and high noise, obtaining the real-time temperature of the engine with high precision is an important guarantee for the safe flight of the aircraft. The temperature sensor currently used in the aircraft engine , The lead wire from the sensor end to the conditioning circuit usually reaches several meters, and it needs to pass through the lightning and EMI filter circuit when entering the c...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem that the wire resistance and protection circuit impedance superposition of the temperature sensor currently used in the aircraft engine will affect the accuracy of temperature acquisition during the signal transmission process, the present invention proposes a high-precision resistance signal conditioning circuit based on a current source. The circuit adjusts the signal of the engine temperature sensor (resistance signal) into a corresponding voltage signal, adopts the measurement method combining the precision current source and the Wheatstone bridge to eliminate the line resistance and the impedance superposition of the protection circuit, and accurately obtains the resistance value of the three-wire platinum resistance through After the AD collector collects, it is processed by the processor, and the circuit also realizes the fault detection function of the resistance temperature sensor to be tested

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