The Foundation's goal for OPC UA was to provide a path forward from the original OPC communications model (namely the Microsoft Windows-only process exchange COM/DCOM) that would better meet the emerging needs of industrial automation.

The transport layer puts these methods into a protocol, which means it serializes/deserializes the data and transmits it over the network.

One is a binary TCP protocol, optimized for high performance and the second is Web service-oriented.

These nodes can include any kind of meta information, and are similar to the objects of object-oriented programming (OOP).

A node can have attributes for read access (DA, HDA), methods that can be called (Commands), and triggered events that can be transmitted (AE, DataAccess, DataChange).

This is necessary to obtain information, if a server only supports DA functionality or additionally AE, HDA, etc.

Various UA Servers have been shown on a Beckhoff programmable logic controller and an embedded test board from Euros.

In October 2012 the German Fraunhofer-Application Center IOSB-INA and the Institute for industrial Information Technologies (inIT) showed that an OPC UA server is scalable down to 15 kB RAM and 10 kB ROM and therefore usable at chip level.

[7] The architecture of a UA application, independent of whether it is the server or client part, is structured into levels.

The portability level is new; it simplifies porting the UA ANSI C stack to other target platforms.

UA Security consists of authentication and authorization, encryption and data integrity via signatures.