BACnetStack_SetIntrinsicChangeOfDiscreteValueAlgorithm

bool BACnetStack_SetIntrinsicChangeOfDiscreteValueAlgorithm(
  const uint32_t deviceInstance,
  const uint16_t objectType,
  const uint32_t objectInstance,
  const uint32_t timeDelay,
  const bool useTimeDelayNormal,
  const uint32_t timeDelayNormal,
  const bool enable);

Enables the ChangeOfDiscreteValue intrinsic event algorithm.

No object type applies this algorithm intrinsically: an OctetString Value has no intrinsic-reporting properties (135-2024 cl. 12.41), so this function returns false and changes nothing for every object type except an Event Enrollment whose own algorithm is CHANGE_OF_DISCRETE_VALUE. Deprecated for intrinsic reporting. The CHANGE_OF_DISCRETE_VALUE algorithm remains available to an Event Enrollment object, which can monitor a discrete property of an object. The object must exist and have alarms and events enabled by BACnetStack_SetAlarmsAndEventsForObjectEnabled(…, enabled=true) - an Event Enrollment object carries its own and needs no such call; otherwise this returns false.

BACnet reference: ANSI/ASHRAE 135-2024 clause 13.3.18 (CHANGE_OF_DISCRETE_VALUE Event Algorithm) and clause 12.41 (OctetString Value Object Type).

Parameters

Parameter	Direction	Description
`deviceInstance`	in	The instance number of the device that owns this object.
`objectType, objectInstance`	in	The object for alarms and events: one BACnet Object Identifier, carried as two parameters (see the API conventions).
`timeDelay`	in	The time delay (seconds) the changed value must persist before notifying.
`useTimeDelayNormal`	in	Whether to use a separate timeDelayNormal for the to-normal transition.
`timeDelayNormal`	in	The time delay for the TO-NORMAL notification.
`enable`	in	Initial inhibit state, inverted - NOT a remove. true arms the algorithm; false leaves it armed but INHIBITED through the object’s Event_Algorithm_Inhibit property (or Reliability_Evaluation_Inhibit for a fault algorithm). Both of those properties are made WRITABLE by BACnetStack_SetAlarmsAndEventsForObjectEnabled(), so a remote client can change the state afterwards. To genuinely remove an armed algorithm, disable the object with BACnetStack_SetAlarmsAndEventsForObjectEnabled(…, enabled=false). Recommended value: true

Returns

False: no object type supports this algorithm intrinsically. A device or object that does not exist, or a build without Alarm-and-Event support (STACK_OPTION_ALARMS_AND_EVENTS), also returns false.

Topic: Alarms and events. Declared in CASBACnetStackDLL.h.