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Definition and application

The Open Platforms Communications Unified Architecture Protocol (OPC UA) is one of the most important communication protocols for Industry 4.0 and the Internet of Things (IoT). It delivers a standardization for the access to machines, devices and other industrial systems and enables a exchange of data regardless of the manufacturer. UA is the latest specification of the standard, which enables platform-independent communication through TCP/IP or SOAP connection. UA also allows a machine-readable semantic description of the data.

OPC UA enables access to different types of data in both vertical and horizontal directions. There are components on which OPC UA is directly integrated via so-called gateways (controls, machines, systems), but also aggregating servers. These servers combine the data rooms of individual OPC UA servers and ensure consistency of configuration and online data. The prerequisite for this is a network based on Internet Protocol (IP). “Industry 4.0-capable” components must also be OPC UA-capable according to the latest standards.
The exchange of data takes place via two mechanisms:

  • Client-Server model: UA-Clients use the dedicated services of the UA server and
  • Publisher-Subscriber model: The UA server makes configurable subsets of information available to any number of listeners.