The Research For Remote Fault Diagnosis Key Technology Based On Virtual Instrument

In this thesis demonstration platform for analog circuit remote fault diagnosis system based on Browser/Server model is built with the application of virtual instrument, network and fault diagnosis technology. The platform is a user login module, data acquisition module, data storage module, time and frequency domain waveform display module, Probabilistic Neural Network (PNN) fault diagnosis module, so that the whole platform has good versatility and scalability.Statistics data show that most of the electronic equipment failure is caused by analog circuit fault. So analog circuit diagnosis theory and methods are becoming very popular and also challenging. However, the approaches are limited to deal with fault diagnosis because of the variety and complexity of the analog circuits, especially the large-scale analog circuits with the tolerance or the soft fault. it brings up new challenge to fault diagnosis of the analog circuits, and requires the new theory and approaches for fault diagnosis of the analog circuits.Artifical Neural Network (ANN) have gained quick development and widely applied in many areas. In this thesis,it is principally studied applying PNN to analog circuit fault diagnosis. Computer network technology, on the other hand, is greatly developed. Remote network testing and fault diagnosis technology become a new research projects direction. This Paper focus on the issue of fault diagnosis technology,the application of probabilistic neural networks in remote analog circuit is studied positively.The thesis concentrates on main works as follows:On the basis of analyzing the basic principle,reasoning methods and function peculiarities of some popular fault diagnosis technologies,and their applications in analog circuit fault diagnosis field;On fault feature extraction method and fault data acquisition for analog circuit;On the general methods and diagnosis steps of analog circuit fault diagnosis based on neural network,PNN networks design,training algorithm and the advantages in fault diagnosis.Finally, combined the advantages of PNN,choosing a typical circuit,using Virtual Instruments and MATLAB,are applied to the simulation of fault diagnosis process.The results of simulation show that the remote monitoring and PNN algorithm used in the combination of analog circuit fault diagnosis is feasible and works well, has good application prospects.