the same object from the



the same object from the same client.

Convert Polarsoft BACnet data to the protocol intergration

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Subscribing to Arrays

The spec allows vendors to choose whether to support subscriptions to all or particular elements of the array.


Variable Number of Subscriptions

Each vendor chooses how many subscriptions to an object / property are supported. The spec requires that at least one must be supported. You should assume the list is finite and fairly short.

Its conceivable that subscription space could be wasted by temporary subscriptions from test equipment of software thus denying room for important subscriptions.

It is important to understand how your COV client application handles and reports failed subscriptions as these events can be as important as the event they are attempting to monitor.
Unconfirmed Notifications can be sent without Subscription

The spec allows a device to send unconfirmed notifications for any property of any object to any other device on the network. Thus a device can send changes of a object property that has a wide area interest such as an outside air temperature. The vendor chooses if they wish to implement this, which objects, which properties and the frequency of the notification.

Notifications can be sent without a change of value

The criteria for triggering notification messages requires notifications to be sent if the Status Flags associated with the object change even if the value hasn't changed. This is potentially, important information but a number of data client systems ignore this element of the notification data. 


GE Fanuc Automation
Programmable Control Products
Series 90Ô PLC
SNP Communications
User's Manual
GFK-0529C September 1998
GFL-002
Warnings, Cautions, and Notes
as Used in this Publication
Warning
Warning notices are used in this publication to emphasize that hazardous voltages,
currents, temperatures, or other conditions that could cause personal injury exist in this
equipment or may be associated with its use.
In situations where inattention could cause either p