Access Credential

An Access Credential object represents one credential that a person or asset presents to get through a door, such as a card, a PIN or a fingerprint. It holds the credential’s status, its dates of validity and the access rights it carries. A device exposes one so that clients can see, enable or disable a credential.

Typical uses

• One badge issued to an employee
• A card plus PIN pair that must both be presented
• A visitor pass that expires at the end of the day
• A contractor credential disabled after a project ends

Key properties

Property	What it holds
Credential_Status	Says whether the credential is currently usable or disabled.
Authentication_Factors	The list of factors (card number, PIN, biometric and so on) that belong to this credential. Each factor can be enabled or disabled on its own.
Assigned_Access_Rights	References to the Access Rights objects that decide where and when this credential works. Each reference can be switched on or off.
Activation_Time	The earliest moment the credential is valid.
Expiration_Time	The moment after which the credential stops working.
Belongs_To	A reference to the Access User object that owns the credential.

How it behaves

The standard does not give this type an event algorithm. Access Point objects look the credential up when someone presents it, and report the outcome.

With the CAS BACnet Stack

Enable it with the STACK_OPTION_OBJECT_TYPE_ACCESS_CREDENTIAL build option. Building with STACK_OPTION_OBJECT_TYPE_ACCESS_POINT turns it on as well, because an Access Point resolves a presented credential to an Access Credential object. Add each object with BACnetStack_AddObject. The stack serves only the identifier, type and property list itself; you serve every other property through your property callbacks.

Related object types

Access Point, Access User, Access Rights

Properties

The properties ASHRAE 135-2024 clause 12.35 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.
Description	CharacterString	O	no	no	""
Global_Identifier	Unsigned32	W	yes	yes	0
Status_Flags	BACnetStatusFlags	R	yes	no	Built by the stack from your callbacks.
Reliability	BACnetReliability	R	yes	no	0
Credential_Status	BACnetBinaryPV	R	yes	no	0
Reason_For_Disable	BACnetLIST of BACnetAccessCredentialDisableReason	R	yes	no	0
Authentication_Factors	BACnetARRAY[N] of BACnetCredentialAuthenticationFactor	R	yes	no	No default: the read fails.
Activation_Time	BACnetDateTime	R	yes	no	No default: the read fails.
Expiration_Time	BACnetDateTime	R	yes	no	No default: the read fails.
Credential_Disable	BACnetAccessCredentialDisable	R	yes	yes	0
Days_Remaining	Integer	O1	no	no	0
Uses_Remaining	Integer	O	no	no	0
Absentee_Limit	Unsigned16	O1	no	no	0
Belongs_To	BACnetDeviceObjectReference	O	no	no	A reference to Access User instance 4194303 (none).
Assigned_Access_Rights	BACnetARRAY[N] of BACnetAssignedAccessRights	R	yes	no	No default: the read fails.
Last_Access_Point	BACnetDeviceObjectReference	O	no	no	A reference to Access Point instance 4194303 (none).
Last_Access_Event	BACnetAccessEvent	O	no	no	0
Last_Use_Time	BACnetDateTime	O	no	no	No default: the read fails.
Trace_Flag	Boolean	O	no	no	false
Threat_Authority	BACnetAccessThreatLevel	O	no	no	0
Extended_Time_Enable	Boolean	O	no	no	false
Authorization_Exemptions	BACnetLIST of BACnetAuthorizationExemption	O	no	no	0
Reliability_Evaluation_Inhibit	Boolean	O	no	no	false
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Audit_Level	BACnetAuditLevel	O2	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O2	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	""