What's Sweet About OPC UA?

The OPC Foundation, in Scottsdale, Ariz., began work on Unified Architecture a few years ago in an attempt to modernize and enhance OPC, while maintaining compatibility with traditional OPC.

While it’s still officially in draft form, OPC UA is already getting adopted in the marketplace. Its individual parts have been released over the past year with the final parts getting released in just the past couple of months.

Current OPC UA features include:
Complex data built-in—The existing Data Access Specification was enhanced with the release of the Complex Data Companion Specification. In UA, complex data will be the norm.

Enhanced namespace—OPC UA allows for unlimited node types and unlimited relationships. Further, each node may participate in an unlimited number of relationships with other nodes. This ensures that no system will be too complicated for exposure via UA.

Rich base set of services—The base UA specification will define the necessary generic services to browse and query the namespace, read/write data and publish/subscribe events and data changes.

UA-derived specifications—The base UA specification will be purposely generic and not imply much semantics. The bulk of the functional areas addressed by the existing OPC specifications will be derived from the UA base specification.

Scalability—Compared with the existing OPC specifications, UA will scale to much larger enterprise-wide data modeling systems, as well as to much smaller embedded devices.

Reliability and redundancy—UA will build in the necessary diagnostics and features necessary for vendors to build high reliability systems. This includes hooks for redundancy.

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