HistoryExportMarkerFilter (History Export Marker Filter)

This filter exports history data for points with an export marker. To do so, it adds a new query under the schema’s Queries folder (if one does not already exist). A BoundQueryResult references this query.

Figure 70. HistoryExportMarkerFilter properties

To use this filter, expand the ExportMarker node in the palette and drag an HistoryExportMarkerFilter to a location in the station.

You access these properties by double-clicking the HistoryExportMarkerFilter node in the Nav tree.

There is some overlap with the RelativeHistoryComponent, which can select point histories using many different criteria, and an appropriate BaseQuery may also be used to generate history for each export marked point. The HistoryExportMarkerFilter updates the timestamp stored on each ExportMarker, so that the schema sends only recent history records to the remote system (typically records added since the last export).

The History Export Filter container is a JsonSchema nested under the filter. It determines the payload format, and the output from that schema to link to a target transport point to complete the export.

If a point with an ExportMarker has more than one history extension, the schema exports each in turn.

NOTE: Since the ExportMarker relies on being added to a local control point in the station, it is not possible to match histories imported over BACnet or the NiagaraNetwork using this filter. Instead, use a RelativeJsonSchema.

In addition to the standard properties (Enabled, Status, and Fault Cause), the history export filter provides these properties.

Property	Value	Description
Current Export Id	read-only	Provides an ID for the export action. For HistoryExportMarkerFilters, this ID should be linked into the schema output to provide identifying information. Or you could even use a query to select data to include if the target system could infer useful data from it.
Count	read-only	Reports how many export marked histories where processed in the last invocation. It resets when the station restarts.
CurrentQuery		Identifies the query used by the HistoryExportMarkerFilter’s schema. The first query in the Queries folder is linked on start, but it does not have to be the only query, or output first data in the JSON schema.
Columns	CSV text	Defines the columns to appear in the filter. For example, timestamp, value, status.
Update Send Since Time	`true` or `false` (default)	Enables and disables the updating of the timestamp stored on the ExportMarker every time the schema exports history. If `true`, which means the most recent send time was updated, the schema sends only the changed records. If `false`, the schema sends all history records that meet the other criteria.

Actions

Send Since Last Export uses the timestamp stored in each ExportMarker to send only history records that have not yet been sent.