Fault recovery in process control

Fault Recovery in process control requires effective fault detection, diagnosis and recovery schemes, and a fault-tolPi-ant system design. Fault detection and diagnosis involves creating a realistic model of the process, and using this model to analyse for fault conditions. The fault detection principles include feature extraction and pattern recognition, and analogue value limits and rate cf change limits. Fault recovery scheme? cover the realisation of redundancy ana back-up sub-systems, and state restoration techniques in the form of complete shutdowns, backward and forward recovery to a safe operating state. System design concepts include for the development of process control systems towards *hierarchical, level based distribution of functions. The level-based discussion is used as the basis for effective fault tolerant system design. Two case studies are included to show how fault recovery schemes were effected in a single process computer and in a distributed control system. Abstract