The Publisheris the PubSubentity that sends NetworkMessagesto a Message Oriented Middleware. It represents a certain information source, for example, a control device, a manufacturing process, a weather station, or a stock exchange.

Commonly, a Publisheris also an OPC UA Server. For the abstract PubSubconcepts, however, it is an arbitrary entity and should not be assumed to be an individual or even a specific network node (an IP or a MAC address) or a specific application. A Publishermay consist of one or more network nodes sending messages and management node(s) responding to discovery probe messages and providing an OPC UA Serverfor configuration and diagnostics.

Figure 5illustrates a Publisherwith data collection, encoding and message sending.


Figure 5– Publisher details

A single Publishermay support multiple PublishedDataSetsand multiple DataSetWritersto one or more Message Oriented Middleware. A DataSetWriteris a logical component of a Publisher. See further information about the DataSetwriting process.

If the Publisheris an OPC UA Server, it can expose the Publisherconfiguration in its AddressSpace. This information may be created through product-specific configuration tools or through the OPC UA defined Methods. The OPC UA Information Modelfor PubSubconfiguration is specified in Clause 9.