Distech Controls ECLYPSE APEX

131ECLYPSE APEX
Inter-Building BACnet Connection
BACnet network connections between buildings must be made using BACnet/IP as shown below.
ECLYPSE
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Externally
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ECLYPSE
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Externally
Set
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ECLYPSE
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Externally
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Figure106: Typical Inter-Building Connection Using BACnet/IP or FOX
BACnet/IP Broadcast Management Device Service (BBMD)
Though BACnet/IP uses IP protocol to communicate, a standard IP router does not forward broadcast
messages which are important in BACnet to identify services that are available within the BACnet in-
ternetwork.
When two ECY Series Controllers communicate to each other over a standard IP connection that is
separated by an IP router, both controllers need the BACnet/IP Broadcast Management Device
(BBMD) service to be configured and operational.
The BBMD service identifies BACnet messages on the BACnet MS/TP network that are intended for a
device located on another BACnet network. The BBMD service encapsulates these messages into an
IP message to the appropriate BBMD service of the other BACnet MS/TP network(s). The BBMD ser-
vice on these networks strips out the encapsulation and sends the BACnet message on to the appro-
priate devices.
When sending BACnet messages across a standard IP connection that has an IP router, there must
be one BBMD service running on each BACnet MS/TP network.
BACnet MS/TP Communication Data Bus Fundamentals