OPC UA is an operating-system-independent architecture that removes the COM/DCOM dependency of classic OPC. It does not only transport data; it models assets, their attributes and relationships in an address space, so a temperature value carries its unit, range and owning device with it.
Besides the client/server model it supports publish/subscribe (PubSub) communication. Security is built into the protocol: certificate-based application authentication, message signing and encryption, and user authentication. Industry-specific companion specifications let machine builders publish shared data models.
In practice OPC UA is one of the most common source protocols for collecting data from PLCs and SCADA systems; platforms such as HighByte Intelligence Hub can act as both an OPC UA client and server.
