Analysis of service-oriented architecture approaches suitable for modular process automation

Evolution in global markets for chemical and pharmaceutical goods requires new approaches in process plant design. Modularization is commonly considered as a promising approach to face the challenges of changing production environment. In order to exploit the advantages of process modularization, new structures of communication and control are required for modular process automation. Service-oriented architecture has been introduced as a promising communication infrastructure combined with state-based control of services. This paper introduces requirements of modular process automation and general requirements of service-oriented architectures. Process functions are represented by encapsulated services in the control level of the automation pyramid. Interaction between a superior control system and intelligent modules is described. Furthermore, approaches of service-oriented architecture are introduced such as a reference model as well as specific implementations of services within modular automation. Subsequently, four different service-oriented architecture approaches are analyzed with respect to their fulfilment of the presented requirements. Finally, this paper discusses the result of the analysis and the general applicability of service-oriented architectures for modular process automation.