Fault Diagnosis And Safety Evaluation System For The Production Process

Signed directed graph (SDG) is a qualitative method for fault diagnosis.Inthe SDG mode,the nodes represent variables of the system, and the branchrepresent direct influence relation between variables of the system. SDG iswidely used and studed, because it could vivid express the spread of fault.Because the SDG method needs higher professional background knowledge andspend a lot of time in the model construction, inference and SDG drawing, thefault diagnosis and safety evaluation system will become very complicated,when the degree of complex large system higher and production scale of thesystem. So developing a computer-aided system based on SDG method, has theimportant practical significance.The main work of this paper are as follows.(1) The related theory was introduced, include basic concepts and therealization of the reasoning methods which include the hierarchical SDG method,fault diagnosis, safety assessment and drawing the SDG.In the system aimproved method is used, which combine algorithm for hierarchical SDG, faultdiagnosis and safety evaluation. The fault source should be in the highest layer which contains the fault nodes in the hierarchical SDG, the the fault sourcecould be found by using the improved algorithm for fault diagnosis. By usingthe breadth-first traversal with fault source as the the beginning point, the results,the fault transmission routes and the status of the nodes in the routes, could begotten. Therefore, the safety evaluation for the system could be accomplished byquerying the results.（2）A detailed description of the system design, including requirementanalysis, The developing process of Django, system architecture, user interfaceand system deployment. Developing the system for fault diagnosis and safetyassessment based on SDG model. The system which based on the open sourceDjango framework, has many characteristics, such as easy to use, maintain,update and recycle. The new computer-aided system supports the online storageand editing the system model, upload the text file containing the information ofthe system model， transmission routes of fault, automatic drawing thehierarchical SDG.(3) Through the complexity example of the Tennessee Eastman process(Tennessee-Eastman, process, TEP), the effectiveness and the completeness ofthe results of the system were verified.