Below are graphical illustrations of typical event
timelines and how they relate to the event triggers on a single equipment
item.
This is an example of a typical event. The setup time period is the time prior to the event start that is used to set up the event. The teardown period is the time required to tear down the event to prepare for the next event.
Single Action Triggers
The event triggers shown as arrowheads are single action triggers. Single action triggers are “one-shot” triggers and do not observe pre-start or post-stop settings.
The above timeline shows a single equipment item with several rooms assigned to the “zone”. Single action zone triggers are shown with their associate trigger points in the timeline. Zone actions trigger off the first events and last events of the day.
Dual Action Triggers (Event Start/Stop, Event Setup/Teardown, Zone First/Last Start/Stop, Zone First/Last Setup/Teardown)
The above example illustrates the dual action trigger. Dual action triggers are combined start and stop triggers for the event period or for the entire reserved (booked) time. The event also shows pre-start and post-stop times added to the beginning and ending of the event timeline. Pre-start time is the amount of time in minutes to start the equipment prior to the scheduled start time. The post-stop time is the amount of time the wait before the stop command is issued after the scheduled stop time. Dual action triggers employ the pre-start and post-stop times saved in an equipment item.
This example shows two events occurring in the same room at back to back times. For this case, the start command with begin at the pre-start for event 1 and the stop command will be sent after the post-stop time for event 2.
The above timeline shows a single equipment item with several rooms assigned to the “zone”. Dual action zone triggers are shown with their associate trigger points in the timeline. Zone actions trigger off the first events and last events of the day.
New Feature (v1.3.5): Post-stop time can now be negative (-) to shut off HVAC prior to the end of the scheduled event. This will allow the system to coast to the end for additional energy savings. Example post-stop of -30 minutes would stop the system 30 minutes prior to the event stop time.
Note: Excessive pre-start times and post-stop times will prevent the desired energy savings and could prevent a unit from shutting down in between events due to the overlapping schedules.
Minimum Stop Gap Time
Starting in v1.4.6, you can define a minimum stop gap time in minutes between successive (dual action) events. This will prevent equipment short cycling if the calculated equipment stop time and the next equipment start time is less than the minimum stop gap time.
Minimum stop gap time is not applied to Zone First/Last event triggers since presumably short-cycling of these types of commands would not occur.
The maximum allowed minimum stop gap time is 120 minutes.
The following shows how the minimum stop gap time keeps a system on.
Minimum stop gap time is not applied to Zone First/Last event triggers since presumably short-cycling of these types of commands would not occur.