A Holistic Design Concept to Improve Safety Related Control Systems

Every complex control process is formed by three types of resources. These Software, Hardware and Liveware resources interact with each other, they are mutually dependent, and they are embedded in a given Environment. However, one common pitfall of traditional design approaches is that they do not consider this systemic view appropriately. We propose a holistic design methodology based on this concept of SHEL for all phases of the design process: understanding the whole system, the activities performed, the criticality, and the knowledge that was created when breakdowns were encountered; and designing not just the artifacts to be introduced, but rather the complete work environment, including the processes, operators' jobs, formal procedures and training. Evaluation, iteration, and user participation are key characteristics of this holistic design approach.