According to the BACnet protocol documentation:

Specifies the date and time of the last use of the credential at an access controlled point, independent of whether access was granted or denied. If the credential this object represents has never been used, then this property shall have the value X'FF' for all date and time octets.

Property lastUseTime of object accessCredential can be read and written using a single IOTag.

Text Parameters

Numeric Parameters

Tag Value

A Date, Null or String (Xml) value representing a BACnet date/time.

•A null value means the date/time is empty/not set;

•A date/time value representing a precise date and time;

•A character string containing an XML with a value of type <BACnetDateTime>.