Service-Orientation and Flexible Service Binding in Distributed Automation and Control Systems

An experimental study shows the feasibility of service-oriented architectures for industrial automation and control systems even with respect to lower, real-time dependent control functions. For that purpose, general SOA-guidelines were refined in order to cover the distribution of control functions between services and the lay-out and management of device-based sensor, actor and control services. Particular emphasis was placed on the dynamic lease-based binding of services which on the one hand provides flexible and loose coupling of system components but on the other hand has to ensure reliable communication and cooperation. The guidelines were applied to the experimental implementation of a manufacturing cell control system using a real-time version of the Java runtime environment. The device profile for Web services (DPWS) was used as basic infrastructure technology. Test and evaluation were performed under distributed simulation of technical processes and devices. We shortly describe DPWS, present the architecture guidelines, outline the experimental control system implementation, and report on its evaluation.