Selecting the Points

In some cases the Gateway shall export all polled points to DCH. Typically this would be required where a new gateway is specifically installed to export to DCH and only the necessary points in the BMS are discovered and added to the gateway.

In other cases, a subset of points shall be exported to DCH. Typically this would be required where a pre-existing controller has the MQTT driver installed and performs the export. In this situation, as not all controller points are being exported, a method to select the necessary points is required. The best option is dependent on the controller and existing point and folder structures, and the following options exist for selecting the points:

1. Have export points organised (or linked to new points placed) into specific folders

2. Tag export points

A combination of both options can also be used (e.g. find points within a specific folder AND having a specific tag).

The method for selecting points will need to be suitable for use with the MQTT and JSON drivers installed in the controller.

For the Jace example, a JsonExportMarker is applied to points that are to be exported to DCH. The addition of this tag creates a slot in each point called JsonExportMarker. The BaseQuery in the RelativeJsonSchema searches the Configuration folder for all control points that contain a slot with name like JsonExportMarker. A custom site marker tag (e.g. dch:Armidale, dch:Newcastle) could also be applied to points to allow selection of points from specific sites to be sent to separate data sources.

It is possible to batch apply the JsonExportMarker and tags to many points using the Niagara Program Service. This can be used to apply tags to all points in a specific folder, or all points with say “Energy” in the name. Many other search options are available.