A Research And Implementation Of Testability For The System Based On Multi-signal Model In Design And Analysis

With the development of science and technology, large-scale systems and equipments are becoming more and more complex. Most of systems are found to be lack of the fault-detection ability and raise the test and maintenance cost. The most important thing is to test and maintain system after having developed a system. So how to get the fault detection rate, isolation rate, ambiguity, false alarm rate and some other useful data in such a system with the complex structure and function, analyze during the evaluation and design, to ensure that improving futher and maintaining the system.This thesis describes a hierarchical modeling which uses a top-down or bottom-up approach, even a mixture of them on complex systems by modeling with multi-signal flow based on testability research.Software is able to integrate different kinds of multi-signal flow diagrams into a whole environmental model and build some complete faulted-dependency testable models with multi-signal flow.Then we can do some testability designs and faultdiagnosed analyses on system or subsystem layer, and get a faulted-dependency matrix of system and testability analyses by using the established faulted-dependency testable models with multi-signal flow.After analysing the system models, it would generate some design evaluation,such as fault detection rate/fault isolation rate, ambiguity groups, and generate and output ambiguity group reports, redundant testability reports, undiagnosable fault sources reports, diagnostic circuit reports, testability indexes(system diagnosis rate, isolation rate, ambiguity group histogram, testable usage histogram), diagnosis tree reports,and so on.After analyzing, system testability defects(e.g. uncovered faults, redundant tests, ambiguity groups, and closed loop) can be obtained in software running process. At the same time, the software provides test reports on chart and text, and diagnosis process can be combined with technical manuals in other field or automatic testing equipment in order to assist system designers to improve the ability of system testability design.