The Priority Array is a command prioritization mechanism
The Priority Array is a command prioritization mechanism. The highest priority is the lowest index and a non-NULL value will represent the active command.
When overriding a commandable BACnet property the values are written to the BACnet Priority Array and Relinquish Default. When overriding non-BACnet points the override priority array is stored locally on the hub.
Priority Array Illustrated
BACnet Standard Common Command Priorities