PI points and PI AF elements and attributes creation

After the connector read the OpenPCS 7 objects (that is, after it has built the in-memory replica of the OpenPCS 7 hierarchy) it continues with the PI AF database creation and building of PI AF elements, attributes, and PI points.

The OPC UA server for OpenPCS 7 organizes its underlying entities as a flat list of objects called process groups. From within the process group names the connector takes a notion of a hierarchy (delimited strings) and builds the PI AF structure. See the figures in section Introduction to PI Connector for Siemens SIMATIC PCS 7 data where the PI AF hierarchy building principle is depicted.

OpenPCS 7 variables are divided into two groups: static (constants) and dynamic (real-time values). Static variables are converted to PI AF attributes and dynamic variables become PI points. The connector decides if an OpenPCS 7 variable is static or dynamic according to the following rule: Static variables are all variables which have a hash '#' character in their display name. For example: FIC_Feed/PID.BatchID#Op_Level

Note: An exception to this rule is when the #Value pattern is found within the variable name, such variable is then considered dynamic. For example: Units/Drain/2U303_9/V3.Permit#Value

Variables which do not have the '#' character in their display name are treated as dynamic. For example: FIC_Feed/PID.BatchID

The naming convention for PI points is as follows: PCS7.DataSourceName.NodeIdNamespaceIndex.NodeIdIdentifier

The PI point name consists of the PCS7 prefix followed by the configured data source name, then NodeIdNamespaceIndex, NodeIDIdentifier. The delimiter is dot '.'.

For example, a dynamic variable with NodeId ns=1;s=t|PCS7DEMO_PRJ_OS(1)::FIC_Feed/PID.BatchID will be accompanied by a PI point: PCS7.DataSourceName.1.t_PCS7DEMO_PRJ_OS(1)::FIC_Feed/PID.BatchID