Interfacing an Expert Diagnostic Tool to Real Time Data

Abstract

SYSTEMS that operate in real-time have stringent operational requirements and are particularly vulnerable to failures in their controls. Accurate fault diagnosis and speedy repairs are essential in such systems. A microcomputer based expert system, CHAMBER2, for control failure diagnosis support in a system of environmentally regulated plant research chambers has been developed. It is a dynamic system and is sufficiently autonomous to be used regularly. The expert system development environment used in this project has the capability to exit the heuristic knowledge base and run high-level language programs, passing information to and from the knowledge base. Using this feature CHAMBER2 has access to data bases and has communications links with the control computer that give it direct access to sensor measurements in real-time. These features minimize the requirement for data entry from the user and increase the availability of accurate data to the expert system. The shell software also provides for cycling through the knowledge base, facilitating real-time operation. When it (CHAMBER2) polls the sensors and finds no problems, it reinitializes the knowledge base and looks again without requesting user observations. The emphasis in this development was on the integration of data bases, sensor data, and cycling in real-time. Future work will emphasize development of feedback from the expert system to the control program.