Aiding the operator in process control emergencies

This paper poses a set of questions of interest to the human operator of a process control plant in emergencies, and it discusses what in theory can be measured and what in theory should be displayed. (It explicitly makes no claim that the ideas are immediately practical, though they may be useful for modeling and understanding the human-machine interactions.) Distinctions are made between controlled process physical state, automatic controller physical state, and system performance state, as well as prediction and confidence estimates of these. Also discussed are techniques for how abnormalities can be detected and identified so that the above states can be predicted, how the operator and the physical system are constrained by time and other factors, and how the operator's attention allocation to plant information systems might be modeled. Finally are some ideas about how computer-based decision aids might become more user-friendly. Copyright (C) 2001 IFAC.