OPC Unified Architecture (OPC UA) is a machine to machine communication protocol for industrial automation developed by the OPC Foundation. Distinguishing characteristics are:
Focus on communicating with industrial equipment and systems for data collection and control
Open - freely available and implementable under GPL 2.0 license
Cross-platform - not tied to one operating system or programming language
Service-oriented architecture (SOA)
Inherent complexity - the specification consists in 14 documents totalizing 1250 pages
Integral information model, which is the foundation of the infrastructure necessary for information integration where vendors and organizations can model their complex data into an OPC UA namespace to take advantage of the rich service-oriented architecture of OPC UA. There are over 35 collaborations with the OPC Foundation currently.
Key industries include pharmaceutical, oil and gas, building automation, industrial robotics, security, manufacturing and process control.