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BACnet Notification Class Display Object


Display microblock

The BACnet Notification Class Display Object microblock defines a standardized object that represents and contains information required for the distribution of alarm notifications within BACnet systems.

Notification Classes are useful for alarm-initiating objects that have identical needs in terms of how their notifications should be handled, what the destination(s) for their notifications should be, and how they should be acknowledged.

A notification class defines how alarm notifications shall be prioritized in their handling according to TO-OFFNORMAL, TO-FAULT, and TO-NORMAL alarms; whether these categories of alarms require acknowledgement (nearly always by a human operator); and what destination devices or processes should receive notifications.

The purpose of prioritization is to provide a means to ensure that alarms or alarm notifications with critical time considerations are not unnecessarily delayed. The possible range of priorities is 0–255. A lower number indicates a higher priority. Priorities may be assigned to TO-OFFNORMAL, TO-FAULT, and TO-NORMAL alarms individually within a notification class.

It is often necessary for alarm notifications to be sent to multiple destinations or to different destinations based on the time of day or day of week. Notification Classes may specify a list of destinations, each of which is qualified by time, day of week, and type of handling. A destination specifies a set of days of the week (Monday through Sunday) during which the destination is considered viable by the Notification Class object. In addition, each destination has a FromTime and ToTime, which specify a window, on those days of the week, during which the destination is viable.

If an alarm that uses a Notification Class object occurs and the day is one of the days of the week that is valid for a given destination and the time is within the window specified in the destination, then the destination will be sent a notification. Destinations may be further qualified, as applicable, by any combination of the three alarm transitions TO-OFFNORMAL, TO-FAULT, or TO-NORMAL.

The link to this device is established in SiteBuilder, and the Object Instance setting in the display input allows the user to link to a specific object within that device.

The input is most often used to display information from other vendor's equipment on WebCTRL Graphics and Properties pages, creating a display of that equipment. The operator can then read and write to the equipment as appropriate.

The BACnet Notification Class Display Object microblock can be used to import multiple properties from a single object, however, to prevent unnecessary network traffic you should only import properties which are actually needed for the intended task. Use the buttons in the Present column to select which properties to get.

Properties

NOTE  Alt+click any value in WebCTRL to view property details, including its expression and editing privilege.