OPC UA Pub/Sub completes the manner in which communication partners interact using the OPC standards. OPC UA Pub/Sub does not follow the client-server communication as OPC UA does with 1-to-1 connections. In OPC UA Pub/Sub, the communication partners are separated into Publishers and Subscribers. The Publishers can send without a connection to a Client and the Subscribers receive sent messages on demand.
Less complex communication can be achieved by decoupling sender and receiver. n-to-m relations are possible through the Companion Specification strategy in communication.
Pub/Sub communication aims at two target sectors in practice. On the one hand, close to-machine and close-to-device communication. For the first time, Pub/Sub can be used to establish real-time OPC communication that can also be implemented by devices with low computing capacities. On the other hand, Pub/Sub communication is very common in the cloud and IoT sector. Due to the very simple structure of the communication channel, for example with an MQTT substructure, a simple connection of cloud platforms is possible.
The OPC Router can operate with the new OPC UA Pub/Sub Plug-in as a Publisher and as a Subscriber. Due to the modularity of the OPC Router, all other plug-ins can also be operated simultaneously with the OPC UA Pub/Sub plug-in and therefore “publish” and “subscribe” data.