Dr. Jörg Nagel, Senior Expert Industry 4.0 - Industrial Internet Solutions Pepperl + FuchsOPC UA is a successor protocol that goes much deeper and offers functionalities that OPC classic did not yet contain. For example, OPC UA is platform independent. The decisive advantage that makes OPC UA very interesting for the realization of a communication in the sense of the industry 4.0, however, represents the universal data model.
What was defined by the application developer in OPC Classic is now uniform regardless of manufacturer. The service-oriented architecture of OPC UA allows any information technology system to access data sources in the field. For integration, no special communication paths need to be maintained; a simple network access is sufficient. A device with an OPC UA server can thus be easily integrated into existing systems.
Standardized communication protocol for industry 4.0OPC UA does more than just transfer data from A to B. The actual transport layer is supplemented by a semantic data model, which enables semantic interoperability between all communication partners. From the field level, for example, intelligent sensors, not only the actual measured values are passed on in the form of process data, but also information about the form, meaning, relationships and structures of the data. From the IT level OPC UA can directly access the sensors. The simple interpretation of the data is ensured by a kind of "self-disclosure" of the sensor containing its capabilities.
Development to the global protocolI think it will take a little while until everyone agrees globally on a protocol, for example, with the connection to cloud solutions is possible. Currently, a publish / subscribe mechanism, as is common in message-based systems, is under development for OPC UA. Furthermore, OPC UA is not yet suitable for hard real-time applications because the underlying TCP / IP does not have a determinacy. Concepts to expand the transport layer accordingly, for example through TSN (Time-Sensitive Networking), already exist.
It is expected that such extensions will find their way into the standardization of OPC UA in the near future. A universal protocol is absolutely necessary with a view to global networking - otherwise production processes will only ever be able to communicate in corporate and country structures. With its standardized data model, OPC UA is well positioned in the race for first place. We should use the current advantage to establish OPC UA as the communication protocol through which each element can communicate with all others. Because this is exactly the prerequisite for the industry 4.0.