If using PubSub as a communication model, the ConnectionConfigurationSet contains a PubSubConfiguration Variable for each AutomationComponent’s CommunicationModelConfig that has a DataType that is a large structure. This structure is passed to the EstablishConnections Method to provide the required information to the AutomationComponent to configure PubSub communication on that AutomationComponent. Some information that is inside of this data structure may need to be adjusted by an OPC UA Client (see 5.5.2). To facilitate this possible adjustment, some aspects of the large structure are exposed as Variables in the ConnectionConfigurationSet.
Figure E.25 illustrates the relation between elements in the ConnectionConfigurationSet and the PubSubConfiguration. Note that for clarity, parts of the ConnectionConfigurationSet are omitted. For an overview of all elements in the ConnectionConfigurationSet, please refer to 6.8.
Figure E.25 – ConnectionConfigurationSet and PubSubConfiguration
Each AutomationComponentConfiguration listed in the ConnectionConfigurationSet has its individual PubSubCommunicationModelConfiguration. The PubSubCommunicationModelConfiguration holds the PubSubConfiguration (highlighted in green with a dashed line).
The following elements within the ConnectionConfigurationSet are related to the PubSubConfiguration (highlighted in red with dashed-dotted lines):
- ConnectionEndpointParameter Variables CommunicationLinks, PreconfiguredPublishedDataSet, and PreconfiguredSubscribedDataSet are related to DataSetReader and DataSetWriter in the PubSubConfiguration;
- PubSubCommunicationFlowConfiguration Object including its SubscriberConfiguration child Objects and SecurityKeyServerAddress Object, contain Variables related to PubSubConnections, ReaderGroups and WriterGroups in the PubSubConfiguration.
All of the related Variables are of SelectionListType, which allows limiting the choice that can be made (see 6.8.1). After a ConnectionConfigurationSet is edited (see 6.7.4), the ConnectionManager reflects the changes into the PubSubConfiguration.
The PubSubConfiguration may be generated by an engineering tool or by the ConnectionManager.
Clause E.6 indicates PubSubConfiguration settings, which are based on using UDP-UADP as the transport profile and UADP-Periodic-Fixed as the header layout profile. Details for other transport or header layout profiles may be added in a later version of this document.