Access Door

An Access Door object represents a door in an access control system. A client can lock or unlock it, and can read whether it is open, locked or held open too long. It models the door hardware itself, separate from the Access Point that decides who may pass.

Typical uses

• A main entrance lock unlocked by a schedule
• A fire exit that reports when it is propped open
• A pulse-unlock for a delivery bay door
• A server room door alarmed when forced

Key properties

Property	What it holds
Present_Value	The commanded state of the lock, such as LOCK, UNLOCK or a timed unlock pulse. Clients write it to operate the door.
Door_Status	The physical state of the door, such as open or closed.
Lock_Status	The state reported by the lock mechanism.
Door_Pulse_Time	How long the lock stays released for a pulse-unlock command.
Door_Open_Too_Long_Time	How long the door may stay open before it raises a door-open-too-long alarm.
Door_Members	The physical doors that this object stands for.

How it behaves

Present_Value is commandable: writers use priorities 1 to 16, and the lowest-numbered priority wins. The standard pairs this type with the CHANGE_OF_STATE algorithm for intrinsic reporting, so a client can be notified when the door enters an alarm state.

With the CAS BACnet Stack

Enable it with the STACK_OPTION_OBJECT_TYPE_ACCESS_DOOR build option and add each object with BACnetStack_AddObject. The stack always treats it as commandable. Present_Value is an enumerated value, and the stack reads and writes the priority array through the callback you register with BACnetStack_RegisterCallbackGetPropertyBool and the BACnetStack_RegisterCallbackGetPropertyEnumerated callback, and writes through the BACnetStack_RegisterCallbackSetPropertyEnumerated callback. It never calls the plain Present_Value getter. Arm the alarm with BACnetStack_SetAlarmsAndEventsForObjectEnabled and then BACnetStack_SetIntrinsicChangeOfStateAlgorithmEnum; each call adds one door alarm state to Alarm_Values.

Related object types

Access Point, Access Zone, Binary Output

Properties

The properties ASHRAE 135-2024 clause 12.26 defines for this object type.

How to read the table:

• Conformance is what the standard asks of every object of this type: R is required, W is required and writable by a client, O is optional. A digit after the letter marks a condition in the standard that decides when the property is present or writable, such as support for intrinsic reporting.
• Present by default: yes means the stack presents the property as soon as you add the object; no means it is optional and you turn it on with BACnetStack_SetPropertyEnabled. This is the stack’s starting setup, so it can differ from the conformance code.
• Writable is whether a client can write the property by default. Change it with BACnetStack_SetPropertyWritable.
• not in profile means the stack does not offer this property for this object type.
• Value when your callback does not answer: “Held by the stack” means the stack stores and serves the value itself and does not ask your callbacks. Otherwise it is the value the stack answers when your callback declines or is not registered.

Property	Datatype	Conformance	Present by default	Writable	Value when your callback does not answer
Object_Identifier	BACnetObjectIdentifier	R	yes	no	Held by the stack.
Object_Name	CharacterString	R	yes	no	"Object <type>,<instance>", such as "Object 0,1" for Analog Input 1.
Object_Type	BACnetObjectType	R	yes	no	Held by the stack.
Present_Value	BACnetDoorValue	W	yes	yes	Built by the stack from the priority array your callbacks serve, or Relinquish_Default when every slot is empty.
Description	CharacterString	O	no	no	""
Status_Flags	BACnetStatusFlags	R	yes	no	Built by the stack from your callbacks.
Event_State	BACnetEventState	R	yes	no	0
Reliability	BACnetReliability	R	yes	no	0
Out_Of_Service	Boolean	R	yes	no	false
Priority_Array	BACnetARRAY[16] of BACnetOptionalDoorValue	R	yes	no	Built by the stack from your callbacks.
Relinquish_Default	BACnetDoorValue	R	yes	no	No default: value-not-initialized until a callback or a client write supplies one.
Door_Status	BACnetDoorStatus	O1,2	no	no (yes while Out_Of_Service is true)	0
Lock_Status	BACnetLockStatus	O1	no	no (yes while Out_Of_Service is true)	0
Secured_Status	BACnetDoorSecuredStatus	O	no	no	0
Door_Members	BACnetARRAY[N] of BACnetDeviceObjectReference	O	no	no	No default: the read fails.
Door_Pulse_Time	Unsigned	R	yes	no	0
Door_Extended_Pulse_Time	Unsigned	R	yes	no	0
Door_Unlock_Delay_Time	Unsigned	O	no	no	0
Door_Open_Too_Long_Time	Unsigned	R	yes	no	0
Door_Alarm_State	BACnetDoorAlarmState	O1,3	no	no (yes while Out_Of_Service is true)	0
Masked_Alarm_Values	BACnetLIST of BACnetDoorAlarmState	O	no	no	0
Maintenance_Required	BACnetMaintenance	O	no	no	0
Time_Delay	Unsigned	O3,5	no	no	0
Notification_Class	Unsigned	O3,5	no	no	0
Alarm_Values	BACnetLIST of BACnetDoorAlarmState	O3,5	no	no	0
Fault_Values	BACnetLIST of BACnetDoorAlarmState	O	no	no	0
Event_Enable	BACnetEventTransitionBits	O3,5	no	no	An empty bit string.
Acked_Transitions	BACnetEventTransitionBits	O3,5	no	no	An empty bit string.
Notify_Type	BACnetNotifyType	O3,5	no	no	0
Event_Time_Stamps	BACnetARRAY[3] of BACnetTimeStamp	O3,5	no	no	No default: the read fails.
Event_Message_Texts	BACnetARRAY[3] of CharacterString	O5	no	no	""
Event_Message_Texts_Config	BACnetARRAY[3] of CharacterString	O5	no	no	""
Event_Detection_Enable	Boolean	O3,5	no	no	false
Event_Algorithm_Inhibit_Ref	BACnetObjectPropertyReference	O5	no	no	No default: the read fails.
Event_Algorithm_Inhibit	Boolean	O5,6	no	no	false
Time_Delay_Normal	Unsigned	O5	no	no	0
Reliability_Evaluation_Inhibit	Boolean	O	no	no	false
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Current_Command_Priority	BACnetOptionalUnsigned	R	yes	no	Built by the stack from your callbacks.
Value_Source	BACnetValueSource	O7,9,11	no	no	No default: the read fails.
Value_Source_Array	BACnetARRAY[16] of BACnetValueSource	O8,10	no	no	No default: the read fails.
Last_Command_Time	BACnetTimeStamp	O8,10	no	no	No default: the read fails.
Command_Time_Array	BACnetARRAY[16] of BACnetTimeStamp	O10	no	no	No default: the read fails.
Audit_Level	BACnetAuditLevel	O12	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O12	not in profile	not in profile	No default: the read fails.
Audit_Priority_Filter	BACnetOptionalPriorityFilter	O12	not in profile	not in profile	No default: the read fails.
Tags	BACnetARRAY[N] of BACnetNameValue	O	no	no	No default: the read fails.
Profile_Location	CharacterString	O	no	no	""
Profile_Name	CharacterString	O	no	no	""