Learn about PI points and AF elements and attributes creation

In the tag-only mode, the connector does not browse the UA address space and works with the list of the specified NodeId from the file described in the previous chapter.

No PI AF objects are created and the PI point names reflect what is specified in the CustomStreamId column, or take the UA NodeId name itself, when the CustomStreamId column is omitted.

In the mode based on UA type definitions, the connector, after it has built the in-memory replica of the OPC UA hierarchy, will continue with the PI AF database creation and the PI AF templates, elements, attributes, and PI points buildup. If no PI AF database is specified, the connector only replicates the OPC UA dynamic variables to PI points.

The connector thus tries to create the closest replica of the discovered OPC UA objects in the PI System. In cases when it is not possible, such as replicating child OPC UA variables to child attributes in PI AF, the connector will continue running without creating the objects. The following naming conventions are applied:

• PI AF element and attribute names are taken from the corresponding OPC UA object's property DisplayName.

• PI points are named according to the OPC UA variable's property NodeId.

  The naming convention the PI Connector for OPC UA applies to PI points complies with the following pattern:

  OPC UA.DataSourceName.NodeIdNamespaceIndex.NodeIdIdentifier

  The delimiter is dot '.'

  For example, an OPC UA dynamic variable with a NodeId:

  ns=5;s=Counter1

  That produces this PI point name:

  OPC UA.DataSource1.5.Counter1

  Moreover, PI points are created with their Eng Units attribute set to the value of an OPC UA property called EngineeringUnits and their Descriptor is set to the value of the OPC UA property called Description. Refer to Collect Unit of Measurement (UOM) metadata for detailed information about which OPC UA properties are involved.

• Variables, which have the HasTypeDefinition reference set to PropertyType are treated as static variables. They are replicated as static attributes on a PI AF element.

  Caution: OPC UA servers support more characters than do PI AF tag, element, and attribute names. In order to mitigate this discrepancy, PI Connector for OPC UA replaces the unsupported characters with an underscore. The following characters are replaced: * ' ? ; { } [ ] | \ ` "
  Consider that PI Connector for OPC UA version 1.0 additionally replaces space characters and ' ' (right and left single quotation marks) with underscores. For more details, see Upgrade PI Connector for OPC UA.