The BacnetNetwork’s Local Device provides a few container slots, found near the bottom of the Local Device’s property sheet (Figure 101).
Apart from the Export Table (see Export Table), these container slots are as follows (note some may be hidden by default, by design):
-
Device Address Binding — (may be hidden) has entries reflecting client-side operation, essentially a list of Device objects (by object ID) and BACnet device address. These identify actual device parameters used when making client BACnet service requests to these devices. For informational use only.
-
Active Cov Subscriptions — (may be hidden) applies to server operation. See Active Cov Subscriptions.
-
Enumeration List — a list of the manufacturer-specific extensions to extensible BACnet enumerations that are defined and applicable for this specific device. In the case of the Local Device, there is no need for editing. In client BacnetDevice components, however, editing items in the Enumeration List may provide utility for proprietary items, perhaps property IDs.
-
Time Synchronization Recipients — (AX-3.4 and later). This and other time synchronization related containers and properties were moved from the
bacnetwsmodule into the corebacnetmodule, with a full collection of properties starting in AX-3.5. They are in the property sheet of any BacnetNetwork’s LocalDevice component. For more details, see Time synchronization properties. -
Utc Time Synchronization Recipients — (AX-3.4 and later). See above description.
The NiagaraAX Bacnet driver provides “server-side Subscribe_COV” to remote BACnet devices (on station objects exposed as BACnet objects). The Active Cov Subscriptions slot in the Local Device contains a dynamic list of current Subscribe_COV subscriptions. Each appears as an Ord to the export descriptor. Figure 102 shows an example with 3 active COV subscriptions.
Depending on the actual implementation, there may be many active COV subscriptions.