BacnetNiagaraHistoryDescriptor is the server log descriptor that exposes a standard Niagara history to BACnet as a Trend Log object, supporting only “by time” or “by index” requests for the trend log data. You use the Bacnet Niagara Log Export Manager view of the BacnetExportTable to add, edit, delete, and access these descriptors.

Alternatively, you can add one of several BacnetTrendLogExt (specialized history extension) to a point—this creates another type of log descriptor. For more details, see log descriptor.