history-HistoryService

Each station contains a single HistoryService. This service provides http access to all of the histories in a station and is responsible for creating the history database, as well as enabling the collection and storage of histories in the database.

To use histories, the HistoryService must be installed on the station. If you do not have the service in your active station, you can add it by dragging and dropping a copy from the history palette, to the Services node in the Nav tree or to the bottom of the Property Sheet view of the Services node, as shown here.

This service manages histories in ways that may not always be visible to you. The HistoryService:

Identifies all existing histories when a station starts and adds them to its list.
Handles history life cycle management, such as the creation and deletion of individual histories.
Maintains the naming convention (namespace) for all histories.
Maintains a global default configuration for the histories.

The History Extension Manager and the HistoryService Property Sheet provide two views for working with history extensions.

Figure 23. History service properties

To access these properties, expand Config > Services, right-click HistoryService, click Views > AX Property Sheet, and expand History Groupings.

Property	Value	Description
History Groupings, History Properties To Group By	three properties for Country, State, City	Configures geographical locations for grouping histories.

Actions

History service actions are available from the popup menu when you right-click the HistoryService node in the Nav tree.

Save Db initiates a save of all histories to the history database.
Close Unused Histories closes any histories that have not been accessed within the Max Open Time (this time is set in the HistoryService Property Sheet).