Design And Implementation Of Automobile Wiring Harness Detection Device Based On STM32

Automobile wiring harness is equivalent to the ’ nerve ’ of automobile.With the popularization of automobile,the demand for wiring harness is increasing rapidly,and the problem of wiring harness quality detection is becoming more and more important.At present,the wiring harness detection and diagnosis technology in China is gradually developing.There are some problems,such as single setting of wiring harness conduction information,high false detection rate and imperfect detection of resistance,capacitance and other components in wiring harness.Therefore,this paper designs and implements an automobile wiring harness detection device based on STM32.The detection device composed of detection circuit module with STM32 as the core,serial touch screen and serial communication module realizes the functions of automobile wiring harness connection fault detection,resistance,capacitance,diode detection,air tightness of detection platform and module lock detection.The screen uses a 10.1-inch capacitive touch screen for design and development,and the design is completed by DGUS(DWIN Graphic Utilized Software)development software.In terms of software,the function of the harness detection device is analyzed to realize the function of issuing instructions through the touch screen and executing each part of the system.On this basis,the auxiliary functions such as self-learning and printing detection harness information are realized,which makes the device more intelligent.Aiming at the problem of high misjudgment rate of level detection and low accuracy of resistance and capacitance detection,the detection method of this device adopts the voltage-controlled constant current source detection method to control different currents flowing through the measured wire or component.The voltage at both ends of the wire is detected by A/D conversion to conduct the automotive wiring harness,and the resistance value is calculated by using the collected A/D value and current value.Then,the comparator,clock and counter are connected to measure the capacitance,so as to realize the accurate measurement of the resistance,capacitance and other components in the wire.The address decoder circuit and analog switch circuit are designed,and the endpoints to be detected are switched to the constant current source output and A/D detection input,which simplifies the detection circuit.The detection device can achieve rapid and accurate detection within 1024 detection points.Through the actual test,the detection accuracy of the wire harness detection device for wire harness conduction detection,module lock,air tightness and so on is 100%,and the actual measurement error of resistance and capacitance is less than 5%(resistance range 50Ω-200KΩ,capacitance range 1n F-1000μF),which can correctly detect the positive and negative installation of diodes.At the same time,the device has a self-learning function,which can learn and record the connection and component information of a variety of standard harnesses.Combined with external storage Flash,it is convenient for operators to manage a large number of different types of harness information.The device has high practicability and broad application prospects.