Downtimeless System Evolution: Current State and Future Trends

Recent studies report a growing demand for downtimeless evolution of distributed automation systems. This paper therefore first analyzes evolution approaches from the industry as well as from academic research pointing out benefits and drawbacks. The standard IEC 61499 is identified as promising basis for dynamic reconfiguration of control applications, but it lacks for an adequate engineering methodology. Finally the epsivCEDAC approach for structured evolution modeling is presented. Therein a distributed evolution control application modeled in terms of IEC 61499 is used for transforming the control application from current to desired state without downtime. Further important issues are correctness of the evolution process and runtime error handling mechanisms.