According to the BACnet protocol documentation:

A unique identifier which is used to globally identify the access controlled zone this object represents. This value may be used to identify Access Zone objects in multiple devices that represent the same access controlled zone. If this value is assigned, it shall be unique internetwork-wide and all Access Zone objects in all devices that represent this access controlled zone shall have this value. A value of zero indicates that no global identifier is assigned.

Property globalIdentifier of object accessUser can be read and written using a single IOTag.

Text Parameters

Numeric Parameters

Tag Value

A 32-bit unsigned integer.