Introduction to PI Connector for Wonderware Historian

Modern industrial facilities rely on Wonderware Historian for the high-performance process database technology required for storing the volumes of data that their operations generate. Combining advanced data storage and compression technology with a query interface, Wonderware Historian provides access to the process, alarm, and event data that is used to monitor operational performance.

PI Connector for Wonderware Historian retrieves historical Galaxy, Area, Object, and Attribute data from the Wonderware Historian database and replicates it in PI Asset Framework (AF) where it is organized for value analysis. See the topic PI AF structure for Wonderware Historian data for more information on how Wonderware Historian objects are organized in PI AF.

The connector provides read-only access to that data using the Wonderware Historian software development kit (SDK).

Note: PI Connector for Wonderware Historian 1.6.8 requires Wonderware Historian SDK 2017 or later, which is available from Wonderware Historian and typically provided in its installation package.

Following is an overview of the standard architecture for a PI system using PI Connector for Wonderware Historian.

PI Connector for Wonderware Historian architecture

Operational overview

PI Connector for Wonderware Historian uses the Wonderware Historian SDK and SQL command data reader to automatically create a hierarchical view of the Historian database, similar to that of the Wonderware ArchestrA model view, utilizing the PI Asset Framework (AF) asset structure and Data References.

The connector creates up to two PI points for each attribute that is contained in the Historian: one for the attribute value, and another for the attribute quality.

At defined intervals, the connector scans the Historian for data to populate the PI AF assets and PI points. PI Connector for Wonderware Historian:

1. Uses regular expression filtering to discover the data hierarchy

2. Creates PI System assets and PI points

3. Collects historical data

4. Uses regular expression filtering to discover the change hierarchy

Wonderware Historian Discovery

After the connector starts, it connects to the Wonderware Historian database and, using SQL command data reader, builds an internal structure of the hierarchy relationships. These relationships are filtered using regular expressions to include or exclude Wonderware tags that match the pattern(s) and/or exclusion of the Wonderware specific types of Analog Real 32, Analog Real 64, Analog Integer 16, Analog Integer 32, Discrete, String, and Quality. These filters are specified during configuration. Modeling occurs in the following order:

5. Wonderware Historian is queried and mapped to the PI System as PI AF assets.

6. Filters are applied to the mapping and any excluded objects are removed.

7. Wonderware area and object types are added to the hierarchy as PI System assets.

8. Wonderware tag attributes are mapped to their parent objects (unless excluded).

9. Wonderware tag attribute values and quality (unless excluded) are mapped to PI System PI points for data collection.

PI System creation

As the connector maps the Wonderware hierarchy, it creates the PI AF database that is specified in the connector configuration. The connector creates a root node asset, whose children are represented by the Wonderware hierarchy under the root asset. Each element representing a Wonderware tag attribute has two PI points for value and quality (unless the points are excluded).

Data Collection

After the mapping of the Wonderware hierarchy is completed, the connector begins sampling the Wonderware Historian for changes to the data using the Wonderware Historian SDK. As the data is sampled, it is written to the respective PI points.

Note: In previous versions of PI Connector for Wonderware Historian, NULL values were replaced with the last good value. In the current version, any NULL values that are received from the historian will be discarded and an information message about the discarded values will be logged. Only NULL values with QualityDetail code 24 will be written a digital state of "Comm Fail" if "WriteIOServerCommunicationFailure" is set to true in the ConnectorGlobal.config.json file.

Mapping synchronization

The PI Connector for Wonderware periodically checks for new tag attributes and their parents as they become available. This includes new tag attributes, Galaxy changes, and Galaxy deployments. PI points are not created for Wonderware tags that have a current value of NULL.

The connector does not delete any endpoints that are created in the PI systems. If a Wonderware tag attribute is deleted or un-deployed the corresponding PI system endpoint stops updating.

Renaming Wonderware objects results in Wonderware generating new tags for all attributes of that object and any child objects. This will also result in new PI AF assets and PI points.

Re-deploying of a Wonderware object that was previously collected by the connector, will only start collecting the values again once the connector is started after the tag was re-deployed.