Evaluation of Fault Detection Coverage of Digital I&C Systems

One of the important features of digital instrumentation and control (I&C) systems is the faulttolerant technique. Fault-tolerance is the system’s capability to help the system perform correctly the specific required functions in spite of the presence of faults. In the fault tolerance evaluation, fault detection coverage is a crucial factor. The fault detection coverage is the ability to detect errors that are caused by faults in a system. If faults are not detected by a certain detection algorithm, the system could be in failure. Evaluating the fault detection coverage of the faulttolerant technique is important for the safety analysis of digital systems [1]. Digital I&C systems have more various fault-tolerant techniques than conventional analog I&C systems. Even though these fault-tolerant techniques are designed to ensure and improve the safety of systems, the effects of them have not been properly considered yet in most system probabilistic safety assessment (PSA) models. There have been several researches into the reliability of digital systems [1]-[4]. However, systematical frameworks or reasonable models to obtain the reliability of digital systems by considering the effects of fault-tolerant techniques have not been proposed. Therefore, it is necessary to develop an evaluation method reflecting the features of digital I&C systems.