Data collection

The OPC UA adapter collects time-series data from selected OPC UA dynamic variables through OPC UA subscriptions (unsolicited reads) or polling (cyclic reads) and event notifications from selected Event Types. The adapter supports the Data Access (DA), Historical Data Access (HDA) and Alarms and Conditions parts of the OPC UA specification. 

For more information, see the following OPC UA Foundation specifications:

• Data Access (https://opcfoundation.org/developer-tools/documents/view/165),

• Historical Data Access (https://opcfoundation.org/developer-tools/documents/view/168)

• Alarms and Conditions (https://opcfoundation.org/developer-tools/documents/view/166)

Data types

The following table lists OPC UA variable types that the adapter collects data from and types of streams that will be created. Types not listed below are currently unsupported.

AVEVA Adapter for OPC UA attempts to verify the data type for each data selection item before adding the item to the subscription on the OPC UA server. Verified data selection items with supported types and data selection items for which the type cannot be verified are added to the subscription. Data selection items with unsupported data type are not added to the subscription and a message including the NodeId and TypeId is logged.

The adapter collects event notifications generated from the standard Event Types available in the OPC UA Server's Event Type library (Event Types folder). The adapter also supports any custom event types that are available on the server. The event fields of the events received are processed as streams of String data type.