Construction of failure diagnosis rules from diagnosis tables

The authors propose a simple method to obtain failure diagnosis rules from a diagnosis table. First, failure distinguishable sets are obtained, and the number of inspection items can be reduced with assuring the system failure distinguishability. Which distinguishable set is available can be determined based on the designer´s preference. The minimal identifiable set for each abnormal event, which corresponds to a diagnosis rule to confirm its occurrence, can be obtained easily. In identifying the system state based on the result of inspection items, the order of inspection items can be determined by the relation graph, which shows how abnormal events are distinguished based on inspection items. The identification process corresponds to that of cutting branches in the relation graph. How to use inspection items can be understood easily based on the relation graph