Research And Design Of Cable Network Resistance Test System

In order to realize the high-efficiency,high reliability and safety test of the complex electronic system cable network,an efficient cable network resistance tester is designed.The test system is made up of PXI chassis,main control card,digital multimeter card and switch quantity card.The test system can detect the resistance of 186 x 186 nodes on cable network,and automatically generate Excel report after completion of test.From the need of testing,the overall scheme of the system is designed,and the hardware of the test system and the software of the upper computer are introduced and analyzed.The hardware aspect is mainly introduced and analyzed from the aspects of digital multimeter card and switch quantity card The main function of the DMM is to measure the resistance between the cable net measuring points.The main function of the switch card is to complete the switching of the measurement channel in the cable network;the software mainly introduces the application language C# of the upper computer,and describes the design of each module which is composed of the upper computer software.This paper mainly introduces the software design of the upper computer of the test system.The system is divided into system setting module,self checking module,parameter setting module and relay inquiry module according to the test requirements.The paper describes the design of each software module,and expounds the key technologies,such as multi thread technology,process / thread priority technology,multi thread data protection technology and dynamic link library technology.In order to improve the precision of the test system,the paper analyzes the rough error,the system error and the random error in the test system,and puts forward the corresponding data processing method.The Romanowski criterion is used to eliminate the gross error of the multimeter.The coefficient calibration method and linear spline interpolation method are used to eliminate the systematic error of the multimeter,and the weight value filtering method is used to eliminate the random error of the multimeter.The analysis of test data proves that the data processing methods adopted are accurate and effective.Finally,the test system is used to test the node resistance of the cable network automatically,and the test results are analyzed to verify the rationality,real time and reliability of the design of the test system.