User Manual

BACnet networks with MS/TP trunks
Application examples
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Question Designing the BACnet network Designing the IP network
Is the number of Desigo room automation
stations between 500 and 2500?
Medium to large project and network of
medium complexity
Does the number of primary plants,
implemented with Desigo PXC, < 200?
Are BACnet third-party devices used? Own UDP port
Is data exchange to Desigo devices (PXC)
required?
Same UDP port
Are equipment rooms, control panels,
distributors distributed over multiple building
sections or floors?
Are the devices to control the primary plants
centrally located in an equipment room?
Plant scope
BACnet network
Plant scope on its own VLAN
Are the control units for the primary plants
decentralized on different floors together with
Desigo room automation stations?
Floor scope
Own BACnet network
Floor scope on its own VLAN
Are BACnet/Desigo devices together on a
separate BACnet network for building, plant,
and floor scope?
Managed layer 2 switches, configuration
of VLAN, and eventually port mirroring
Are different IP networks configured? One BBMD per IP segment is required
with an asymmetrical BDT.
FDT must also be possible if there is a
Desigo CC management platform or
other BAC clients for operation.
Large project
Consider the following questions for detailed planning when designing a large project with a high level of
network complexity:
Question Designing the BACnet network Designing the IP network
Are other disciplines (fire, intrusion, video)
planned on the project in addition to HVAC and
Desigo room automation?
Large project and network of high
complexity
Is the number of Desigo room automation
stations between 500 and 15,000?
Does the number of primary plants,
implemented with Desigo PXC, < 200?
Does building automation and control extend to
multiple properties, buildings, and building
sections?
Multiple BACnet internetworks,
eventually with multiple BACnet
networks
Are there multiple properties or building
requiring a clearly structured IP network?
Layer 3 switches for implementing
multiple IP segments
Is IT security required? Based on local and industry guidelines
5.4 Application examples
The following examples demonstrates network planning and configuring of a BACnet network up to
commissioning in the real world.
The examples illustrate the required clarifications and planning steps, the selection and configuration of
hardware components involved in implementing small to mid-sized, up to large Desigo projects.
We rely on products from the Siemens portfolio in the examples. The network components must meet the
same requirements and function if you can use existing IT infrastructure to implement the project.