Service orchestration with OPC UA in a graphical control language

Production plants need to be set up and reconfigured faster to fulfill increasing market demands. Highly flexible automation systems are needed and a promising approach is Service Oriented Architecture (SOA) which has recently received much attention in both academia and industry. OPC Unified Architecture (OPC UA), the next generation of the de facto standard for interoperability in the automation domain, has SOA capabilities. In this paper it is presented how SOA service orchestration of OPC UA services can be done conveniently with a graphical control language. Generic support to use OPC UA servers has been integrated into the language and as an example it has been used to control a physical process which has been modeled, encapsulated, and exposed as an OPC UA server by wrapping it with an ethernet capable microcontroller.