BACnetStack_SetIntrinsicChangeOfTimerAlgorithm

bool BACnetStack_SetIntrinsicChangeOfTimerAlgorithm(
  const uint32_t deviceInstance,
  const uint16_t objectType,
  const uint32_t objectInstance,
  const uint32_t * alarmValues,
  const uint32_t alarmValueCount,
  const uint32_t timeDelay,
  const bool useTimeDelayNormal,
  const uint32_t timeDelayNormal,
  const bool enable);

Enables the ChangeOfTimer intrinsic event algorithm for a timer 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.

This function will enable the required properties and store the initial values in memory.

The monitored value is the Timer_State (a BACnetTimerState enumeration, cl. 21: idle=0, running=1, expired=2). alarmValues is the algorithm’s pAlarmValues (cl. 13.3.19): the Timer_State values that are OFFNORMAL (typically [expired]). The object transitions to OFFNORMAL when the Timer_State enters any value in alarmValues and back to NORMAL when it leaves all of them, honoring the configured time delays.

Note

Requires all of these build options: STACK_OPTION_ALARMS_AND_EVENTS; and STACK_OPTION_OBJECT_TYPE_TIMER.

BACnet reference: ANSI/ASHRAE 135-2024 clause 13.3.19 (CHANGE_OF_TIMER Event Algorithm).

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).
alarmValues	in	Pointer to an array of the OFFNORMAL Timer_State values: the algorithm’s pAlarmValues list.
alarmValueCount	in	The number of values in the alarmValues array.
timeDelay	in	The time delay for the transition to the OFFNORMAL state.
useTimeDelayNormal	in	Whether to use a separate timeDelayNormal for the to-normal transition.
timeDelayNormal	in	The time delay for the transition back to the NORMAL state.
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

True on success; false if the device or object does not exist, the object type does not support this algorithm, or Alarm-and-Event support was not compiled (STACK_OPTION_ALARMS_AND_EVENTS).

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