According to the BACnet protocol documentation:

Defines a standardized object whose properties represent the externally visible characteristics of a named data value in a BACnet device. A BACnet device can use a Date Value object to make any kind of date data value accessible to other BACnet devices. The mechanisms by which the value is derived are not visible to the BACnet client. A Date Value object is used to represent a single day. In contrast, the Date Pattern Value object can be used to represent multiple recurring dates. Date Value objects may optionally support intrinsic reporting to facilitate the reporting of fault conditions.

Objects of type dateValue have the following properties:

•ackedTransitions

•commandTimeArray

•currentCommandPriority

•description

•eventDetectionEnable

•eventEnable

•eventMessageTexts

•eventMessageTextsConfig

•eventState

•eventTimeStamps

•lastCommandTime

•notificationClass

•notifyType

•objectIdentifier

•objectName

•objectType

•outOfService

•presentValue

•priorityArray

•profileLocation

•profileName

•propertyList

•reliability

•reliabilityEvaluationInhibit

•relinquishDefault

•statusFlags

•tags

•valueSource

•valueSourceArray