A DataSetcan be thought of as a list of name and value pairs representing an Eventor a list of Variable Values.

A DataSetcan be created from an Eventor from a sample of Variable Values. The configuration of this application-data collector is called PublishedDataSet. DataSetfields can be defined to represent any information, for example, they could be internal Variablesin the Publisher, Eventsfrom the Publisheror collected by the Publisher, network data, or data from sub-devices.

DataSetMetaDatadescribed in 5.2.3defines the structure and content of a DataSet.

For publishing, a DataSetwill be encoded into a DataSetMessage. One or more DataSetMessagesare combined to form the payload of a NetworkMessage.

Figure 3illustrates the use of DataSetsfor publishing.

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Figure 3– DataSet in the process of publishing

A PublishedDataSetis similar to either an Event MonitoredItemor a list of data MonitoredItemsin the Client Server Subscriptionmodel. Similar to an Event MonitoredItem, a PublishedDataSetcan select a list of Event fields. Similar to data MonitoredItems, the PublishedDataSetcan contain a list of Variables.

A DataSetdoes not define the mechanism to encode, secure and transport it. A DataSetWriterhandles the creation of a DataSetMessagefor a DataSet. The DataSetWritercontains settings for the encoding and transport of a DataSetMessage. Most of these settings depend on the selected Message Oriented Middleware.

The configuration of DataSetsand the way the data is obtained for publishing can be configured using the PubSubconfiguration model defined in 8.2or with vendor-specific configuration tools.