The OPC Unified Architecture (UA), released in 2008, is a platform independent service-oriented architecture that integrates all the functionality of the individual OPC Classic specifications into one extensible framework.

OPC UA was designed to enhance and surpass the capabilities of the OPC Classic specifications.

OPC technologies were created to allow information to be easily and securely exchanged between diverse platforms from multiple vendors and to allow seamless integration of those platforms without costly, time-consuming software development. Today, there are more than 4,200 suppliers who have created more than 35,000 different OPC products used in more than 17 million applications.

OPC UA is functionally equivalent to OPC Classic, yet capable of much more:

• Discovery: find the availability of OPC Servers on local PCs and/or networks
• Address space: all data is represented hierarchically (e.g. files and folders) allowing for simple and complex structures to be discovered and utilized by OPC Clients
• On-demand: read and write data/information based on access-permissions
• Subscriptions: monitor data/information and report-by-exception when values change based on a client’s criteria
• Events: notify important information based on client’s criteria
• Methods: clients can execute programs, etc. based on methods defined on the server