Two new features of Events2HVAC (v.1.5 and higher) permit users to automate switching between Events2HVAC schedules and backup building schedules in case of lost communication from the server.
All Events2HVAC users are strongly encouraged to take advantage of these features, especially users with large implementations.
BACnet Status Point
If you are using the Events2HVAC BACnet/IP interface to communicate to your HVAC controls, there is a new binary point within Events2HVAC that your controllers will be able to read across the network. This BACnet status point indicates three possible conditions to the controller:
(1) ON – schedules are available and flowing through Events2HVAC as normal
(0) OFF – no schedules are available
OFFLINE – communication with the server hosting Events2HVAC has been lost
To take advantage of this feature, logic must be added to the BACnet-enabled controller to switch to backup HVAC schedules if the status is either OFF or OFFLINE for a specified period of time. Logic must also be added to return to using schedules from Events2HVAC when the status returns to ON.
The new BACnet status point is not enabled by default, so you will need to turn it on to enable this new feature. Learn how here: BACnet Heartbeat
This is the preferred method to automate backup schedules with Events2HVAC if you are using BACnet-enabled HVAC controls. But if your controller cannot read the status point for some reason, you can also use the heartbeat method described below.
If you are using the Events2HVAC Johnson Controls Metasys (MSEA) interface, you can use the new heartbeat feature to automate switching to backup schedules in the event of loss of communication from the server hosting Events2HVAC. (Note: This can also be used with the BACnet/IP interface if your controller cannot read the BACnet Status Point described in the previous section.)
The heartbeat sends a status from Events2HVAC to the MSEA controller(s) every 5 minutes, indicating that the Events2HVAC service is still alive and sending schedules. There are two types of heartbeat signals that can be sent:
Ping: Sends a single command every 5 minutes. (Binary 1, Analog 100). For this type of signal, the controller logic must reset its own point value back to zero once the signal is received.
Toggle Value: Sends alternating commands every 5 minutes. (Binary 0/1, Analog 0/100)
The heartbeat target points can be of type binary value, binary output, analog value, or analog output.
To take advantage of this feature, logic and target points must be added to the MSEA controller(s) to switch to backup schedules if the heartbeat signal has not been received for a defined delay period (15 minutes or more). When the signal comes back (after a delay), the logic should switch back to Events2HVAC schedules.