A self-validating control system based approach to plant fault detection and diagnosis

An approach is proposed in which fault detection and diagnosis (FDD) tasks are distributed to separate FDD modules associated with each control system located throughout a plant. Intended specifically for those control system s that inherently eliminate steady state error, it is modular, steady state based, requires very little process specific information and therefore sho uld be attractive to control systems implementers who seek economies of sca le. The approach is applicable to virtually all types of process plant, whe ther they are open loop stable or not, have a type or class number of zero or not and so on. Based on qualitative reasoning, the approach is founded o n the application of control systems theory to single and cascade control s ystems with integral action. This results in the derivation of cause-effect knowledge and fault isolation procedures that take into account factors li ke interactions between control systems, and the availability of non-contro l-loop-based sensors. (C) 2001 Elsevier Science Ltd. All rights reserved.