There are two primary uses for Bacnet virtual points:
Px view bindings for simple polling of values, without the station resource overhead of (persisted) proxy points. Upon being unsubscribed, virtual components are simply removed from the poll scheduler and also station memory. The only persisted parts are the ords (using virtual syntax) in the Px widget bindings. In many cases, particularly with replicated device applications, this allows a JACE station to graphically monitor many more devices than if using just proxy points.
Quick review and (if needed) adjustments to one or more properties in BACnet objects, from the Workbench property sheets of virtual components. Otherwise, you would typically need to create persisted “Config” type objects, then delete them after reviewing and changing properties.
Virtuals are transient vs. persisted components—they are dynamically created (and subscribed) only when accessed, and are not permanently stored in the station database. This precludes any linking to or from virtuals—as links would be lost. Nor are point extensions (alarm, history) supported under virtual components. These things require use of Bacnet proxy points, which are persisted in the station database.
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