Situation assessment for process control

Extase, a situation assessment system that finds the causes of alarm signals relating to the heating furnace of a distillation column, is presented. The system is centered around two design principles. First, heterogeneous knowledge is represented by causally describing process functions. Second, a hypothesis network that supports local search control, stores time-dependent dynamic information, and forms a basis for the explanation facility is progressively built. The motivations and requirements for this research are examined, the process environment that served as an example is described, and system implementation is discussed. Extase has been installed and tested in a refinery and has completed its first development cycle. The authors describe and discuss system implementation principles in detail. Finally, they present the results of field testing and assess the system´s limits and strengths.<>