Alert Enrollment

An Alert Enrollment object carries information alerts. These are notable messages that are not tied to an alarm algorithm, so they do not change the event state of the object that produced them. In the standard, a device uses one to tell interested clients that something worth knowing has happened. The customer interface cannot raise alerts.

Typical uses

These are the uses the standard has in mind. A customer build cannot raise alerts, so it cannot serve them.

• A notice that a filter change is due
• A message that a configuration was changed
• A heads-up that a backup finished
• A vendor-defined note from an embedded controller

Key properties

Property	What it holds
Present_Value	The identifier of the object that supplied the most recent alert.
Notification_Class	The Notification Class that decides who receives the alerts.
Event_Enable	Selects which transitions are allowed to produce notifications.
Event_Detection_Enable	Turns alert reporting on or off for this object.
Event_State	Stays NORMAL, because alerts do not move the object out of its normal state.

How it behaves

Alerts go out as event notifications with the event type EXTENDED and both states set to NORMAL. The vendor and extended event type values classify the alert, and the first extended parameter names the source object.

With the CAS BACnet Stack

The customer interface cannot raise alerts: CASBACnetStackDLL.h has no function that sends an alert through this object. A customer build can present the object, but not use it. If your product needs alerts, contact Chipkin. The type is on in the full target. In the embedded target, define STACK_OPTION_OBJECT_TYPE_ALERT_ENROLLMENT yourself (see Configuring a build). Add the object with BACnetStack_AddObject; the stack does not serve its property values on its own.

Related object types

Event Enrollment, Notification Class, Notification Forwarder

Properties

The properties ASHRAE 135-2024 clause 12.52 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	""
Present_Value	BACnetObjectIdentifier	R	yes	no	No default: value-not-initialized.
Event_State	BACnetEventState	R	yes	no	0
Event_Detection_Enable	Boolean	R	yes	no	false
Notification_Class	Unsigned	R	yes	no	0
Event_Enable	BACnetEventTransitionBits	R	yes	no	An empty bit string.
Acked_Transitions	BACnetEventTransitionBits	R	yes	no	An empty bit string.
Notify_Type	BACnetNotifyType	R	yes	no	0
Event_Time_Stamps	BACnetARRAY[3] of BACnetTimeStamp	R	yes	no	No default: the read fails.
Event_Message_Texts	BACnetARRAY[3] of CharacterString	O	no	no	""
Event_Message_Texts_Config	BACnetARRAY[3] of CharacterString	O	no	no	""
Event_Algorithm_Inhibit_Ref	BACnetObjectPropertyReference	O	no	no	No default: the read fails.
Event_Algorithm_Inhibit	Boolean	O	no	no	false
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Audit_Level	BACnetAuditLevel	O1	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O1	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	""