About the history property sheet view

Starting in AX-3.5, histories can have properties. Like components, histories have a property sheet view that allows you to view and edit property values. You can add properties to a history (and designate them as metadata, if desired) using the slot sheet view or the metadata browser view. An example of the history property sheet view is shown in Figure 156.

Figure 156. History property sheet view

The history property sheet view is comprised of the default history properties, as described in Configure history extensions and any additional dynamic properties that are added. If you change any of the editable properties in this view then the properties are changed at the actual source of the history, if the source is accessible. For example, in a history property sheet view, if you change a history Full Policy property from Stop to Roll, then, if the “source” is accessible, the history Full Policy property is changed on the appropriate history extension or History Import component (Config Overrides property).

If the history is imported from a NiagaraHistoryImport descriptor or NiagaraSystemHistoryImport descriptor that was made via *export tags* (HistoryImportTag, SystemHistoryImportTag) in the source station, the next export tag Join to/from that station will *overwrite* whatever fullPolicy or other property value changes that were initiated from the history property sheet.

Consider the following examples:

Example 2. Example 1: History imported from remote controller to Supervisor

In a situation where histories are imported to a Supervisor from a remote controller, the source configuration for that history is available on the supervisor Import Descriptor property sheet view. If you change the fullPolicy on the history property sheet view (as shown below), then the same property is changed on that history’s Niagara History Import descriptor component (under the Config Overrides property).

Figure 157. Example 1: History property changes Import Descriptor property

Local histories behave in the same way, since local histories and history import descriptors should always be available to the supervisor station.

Example 3. Example 2: History exported to Supervisor by remote controller

Histories that are exported from remote stations may create histories on the Supervisor that have an unreachable source. In this case:

If the source of a history is unreachable, then the history configuration properties that are modified (under the history properties view on the supervisor) may be overwritten the next time that the history is exported to the supervisor.
History properties that are flagged as metadata properties are not overwritten or dropped when histories are exported to the supervisor. Local metadata property values are persisted as long as they do not have the same name as properties that are being exported from the remote station.

In most cases, it is a better practice to add metadata properties at the remote station if you are doing history exports so that they are exported up to the supervisor station.