Properties of Bacnet export descriptors

Each Bacnet export descriptor has various properties that affect its BACnet representation. Access these properties in the property sheet view of any export descriptor, as shown in Figure 79.

Figure 79. Additional properties of Bacnet export descriptors on property sheet

Some of these properties are BACnet optional properties, such as Notify_Type and Device Type. Others are required, such as Out_Of_Service. The following list describes additional properties in Bacnet export descriptors, not seen in the Add or Edit dialog for the component:

Fault Cause

Niagara-only, read-only property showing an explanatory text string if the export descriptor is in fault. For example, if its Object Id is manually edited to be the same as another existing export descriptor—a fault occurs and the Fault Cause would be “Duplicate Object ID.”
Reliability

BACnet read-only property that reads “No Fault Detected” when things are OK, and typically “Unreliable Other” if the exported BACnet object appears in fault. This might happen, for example, if the source (exported) component is a proxy point under some other driver, and device communications are down, or if the point has been disabled.

In this case, note that the Bacnet export descriptor retains a status of “ok.”
Out Of Service

Writable BACnet property, which you can set to false if needed—this affects the BACnet exposure and access of the source component only. In other words, if the source (exported) component is a proxy point, the equivalent “Enabled” property in its ProxyExt is not affected.
Notify Type

Writable BACnet property that can be set to either Alarm (default) or Event. Applies if the source Niagara component has an alarm extension.
Cov Increment

Writable BACnet property included only for analog object types (Analog Input, Analog Output, Analog Value, Analog Value Priority, Loop), specifying the minimum COV required before a COVNotification is issued to subscriber BACnet COV-clients. Default value is typically 1.00.
Device Type

Writable BACnet property included only for some object types (Analog Input, Analog Output, Binary Input, Binary Output, Multi-state Input, Multi-state Output), typically associated with the type of physical input or output. Use is optional. In NiagaraAX, this might apply mostly to exported Ndio points—where each point corresponds to a physical device.