User Manual

BACnet/IP networks
Designing BACnet/IP networks
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192.168.13.250 - - - - -
192.168.14.250 - - - - -
192.168.16.1 .- - - - -
Function For system
monitoring of the
system level
(Timesync)
Time switch
catalogs global
BBMD
(is the node for
all broadcast
messages
between VLAN
01-07
or between ERR
from floors and
primary plants)
Primary server
Main HVAC plant BBMD in VLAN 1 BBMD in VLAN 2 BBMD in VLAN 3 BBMD in VLAN 4
How and why asymmetrical BDT entries?
Local broadcasts that use the flexible room management to locate and address room segments from the
room, are routed to an own VLAN or BACnet network to a defined UDP port (0xBAC0). Local broadcasts are
thus encapsulated and no longer forwarded to other networks.
BACnet Broadcast Management Devices (through the BDT) must, however, be defined for global BACnet
broadcasts (originating, among others, from central functions) to operate successfully on the different IP
segments and BACnet networks.
From the project topology described above, a PXG3.M (BNR501) must for performance reasons in building
scope:
● Support the BBMD function on the first port.
● Enter its own IP address in the BDT to 0xBAC0 (first port).
● Enter all other IP address for the BBMDs in the other IP segments that also communicated on UDP port
0xBAC0.
A BBMD must be defined for each of the other IP segments.
The BDT is also enabled in FxBNR01 to BAC0. In the BDT is the own IP address and address for BNR501.
For performance reasons, we recommend using a PXG3 (BNR) on the floor scope on a midsize to large
project.
The Desigo CC management platform registers as a third-party device in BNR501. The broadcast can be
triggered here and forward via the asymmetrical BBMD entries to all other participants in the various IP
segments.
The project example illustrated above relies on Desigo room automation stations that support Desigo
Version 6.1. In the event that Desigo room automation stations, version 6.0 are used for various reasons
(project progress):
● Desigo room automation stations in the floor scope must be placed on another UDP port to isolate local
broadcasts (room/room segment).
● The routing functionality must be configured for the BACnet router.
Planning and implementation, HVAC and room automation
Plant scope:
● Desigo PXC…E.D to control primary plants.
Building scope:
● Desigo PXC00-E.D for superposed functions, e.g. scheduler for occupancy and use times by floor.
● Desigo DXR2.E18 for central functions over multiple floors.
Floor scope: