Design And Research Of Portable Cable Fault Detector

The complex electrical cable connections among the apparatus within a large system are critical to the security and reliability of the system. In the event of cable connection failure, serious consequences can occur such as system breakdown, human injuries and interruptions of control command communication, which can even leads to significant losses in economy, politics and military.Effective detection and accurate localization of the point of cable connection failure are essential to a reliable system. However, the existing technologies for the cable failure detection system suffer from a few drawbacks like poor portability, low accuracy, high cost, and so on. In general, an effective cable failure diagnostic system and corresponding foundations need further development. For instance, in large scale entities such as aircrafts and vessels, cables between internal components constitute a complex network with a high coupling level, which it is really difficult to dissemble into pieces and maintain separately. With the current technology, external maintenance cables are required for such applications; however, these cables are generally large in size, expensive, complicated to use and worn out easily. Additionally, malfunctioned external maintenance cables could also cause system failures. Considering all of these circumstances, the self-diagnose will be invalid frequently and the results are not reliable eventually. Furthermore, existing diagnose devices also lack portability, hence they can only be used at certain facilities. In summary, these problems pose potential huge risks to the long-term reliability of large systems.To solve the aforementioned problems to diagnosis cable failures in a large system, a distributed multi-core cable fault detector based on the Controller Area Network(CAN) field bus has been designed and presented in this dissertation. This detector has following features to achieve maximized test efficiency: small size, large cable detection capacity, supporting connectivity and insulation test, supporting vibration test of cable and connector reliability.In this detector, the DSP2812 has been employed as the main microcontroller that its modules can be utilized fully. In addition, an over-voltage protection circuit has been designed, implemented and applied to ensure the electrical safety during test. Forthe benefit of fast and safe channel switching, an array of relay switches has been used.Furthermore, a field bus communication protocol based on a “Command Number +Parameters” template, as well as a test procedure and a master-slave test mechanism have been implemented in software。 Lastly, a DSP driver has also been developed to access and control the detector. Additionally, to facilitate the installation and maintenance of the tool, based on the concept of modulization, every module(e.g.controller, relay array board, dashboard, etc.) of the proposed detector has been refactored. Hence, new module can be easily added when necessary.The functionality of the detector has been successfully demonstrated through intensive software and hardware test; and the testing results satisfied all the design requirements. In addition, the cable failure detector presented in the dissertation is cost effective and achieves an excellent performance. To summarize, it is an improvement to the existing cable failure detection techniques, and can be very valuable socially and economically.