Event Enrollment

An Event Enrollment object watches a property of another object and decides when to raise an alarm or event. It carries its own algorithm, parameters and notification class. In the standard, a device uses one to add alarm detection to objects that have no built-in (intrinsic) reporting, or to monitor an object in a different device. The customer interface cannot set up a working one.

Typical uses

These are the uses the standard has in mind. A customer build cannot set an Event Enrollment up for them; arm intrinsic reporting on your own objects instead.

• Alarm when a temperature input rises above a high limit
• Report a change of state on a point that has no alarm support
• Monitor a property on an object in another device
• Send a notice when a monitored value changes by a set amount

Key properties

Property	What it holds
Object_Property_Reference	Names the object and property being watched. It can point to another device.
Event_Type	Which event algorithm is in use. It follows from the parameters in Event_Parameters.
Event_Parameters	The settings for the chosen algorithm, such as limits, deadband and time delay.
Notification_Class	The Notification Class object that decides who receives the notifications.
Event_State	The current state: normal, off-normal, fault or one of the limit states.
Event_Enable	Which transitions (to off-normal, to fault, to normal) may produce a notification.

How it behaves

An Event Enrollment does not change the object it watches. Which algorithm runs depends on Event_Parameters, not on the watched object’s type. Reliability reports its own configuration or communication problems first, then faults found in the monitored object. Clients read Event_State and Acked_Transitions, and receive notifications through the Notification Class.

With the CAS BACnet Stack

The customer interface cannot set what an Event Enrollment watches: no function in CASBACnetStackDLL.h sets its monitored property, so a customer build cannot make a working one. If your product needs Event Enrollment objects, contact Chipkin. For alarms on your own objects, arm their intrinsic reporting instead. The type is on in the full target. In the embedded target, define STACK_OPTION_OBJECT_TYPE_EVENT_ENROLLMENT yourself (see Configuring a build). The BACnetStack_SetIntrinsic* and BACnetStack_SetFault* setters accept an Event Enrollment directly, without BACnetStack_SetAlarmsAndEventsForObjectEnabled first, because the object carries its own algorithm settings.

Related object types

Notification Class, Alert Enrollment, Notification Forwarder, Analog Input

Properties

The properties ASHRAE 135-2024 clause 12.12 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	""
Event_Type	BACnetEventType	R	yes	no	0
Notify_Type	BACnetNotifyType	R	yes	no	0
Event_Parameters	BACnetEventParameter	R	yes	no	Held by the stack.
Object_Property_Reference	BACnetDeviceObjectPropertyReference	R	yes	no	No default: the read fails.
Event_State	BACnetEventState	R	yes	no	0
Event_Enable	BACnetEventTransitionBits	R	yes	no	An empty bit string.
Acked_Transitions	BACnetEventTransitionBits	R	yes	no	An empty bit string.
Notification_Class	Unsigned	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_Detection_Enable	Boolean	R	yes	no	false
Event_Algorithm_Inhibit_Ref	BACnetObjectPropertyReference	O	no	no	No default: the read fails.
Event_Algorithm_Inhibit	Boolean	O1	no	no	false
Time_Delay_Normal	Unsigned	O	no	no	0
Status_Flags	BACnetStatusFlags	R	yes	no	Built by the stack from your callbacks.
Reliability	BACnetReliability	R	yes	no	0
Fault_Type	BACnetFaultType	O2	no	no	0
Fault_Parameters	BACnetFaultParameter	O2	no	no	No default: the read fails.
Reliability_Evaluation_Inhibit	Boolean	O	no	no	false
Property_List	BACnetARRAY[N] of BACnetPropertyIdentifier	R	yes	no	Held by the stack.
Audit_Level	BACnetAuditLevel	O3	not in profile	not in profile	No default: the read fails.
Auditable_Operations	BACnetAuditOperationFlags	O3	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	""