The UA in OPC UA (IEC 62541) stands for Unified Architecture: OPC UA is a framework, not a single protocol. At its base it specifies services for secure, platform-independent data exchange between applications over certificate-based, session-oriented client/server connections and brokered or brokerless publish/subscribe. Layered above this is its information-modelling framework: devices and processes are modelled as types, and their instances exposed as browsable objects in a server's address space, including alarms, conditions and historized data. Where a community standardises such a model and publishes it as a companion specification, applications that both implement it can exchange data with agreed meaning, enabling semantic interoperability by prior agreement, not by protocol alone.

 Current OPC UA usage at CERN is centered mainly in the detector controls and technical infrastructure systems where adoption has proven to be successful. In the short term, adoption within these fields is likely to expand. Longer term, OPC UA is mentioned as a candidate technology for a middleware backbone in the context of the Next Generation Controls (NGC) program.

We are pleased to invite the OPCFoundation president Stefan Hoppe and OPC UA FX (Field eXchange) director Peter Lutz to present the status and direction of the standard and to discuss the intersection of the evolution of OPC UA with the NGC overview.