OPC UA Nodestore Switch - Usage Scenarios

Abstract

OPC Unified Architecture is one of the leading technologies to realize the horizontal and vertical communication from enterprise layer down to the field layer in automation technology. It defines an address space model consisting of nodes and references without specifying how to store these. Therefore, this paper first describes the concept of a nodestore and a nodestore switch. The core contribution of the nodestore switch is the decoupling of OPC UA servers from their node storage. Based on this, four usage scenarios demonstrate how to utilize the concept to address different requirements, like performance and persistence, the integration of domain specific (proprietary) meta models, the adaptation at runtime and sharing of information models. For each usage scenario a prototypical implementation is described to show an exemplary realization and to gather a deeper understanding of the usage.