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Siemens
Desigo TRA Engineering, mounting and installation
CM111043en_09
Building Technologies
MS/TP networks
2016-02-22
10 MS/TP
networks
10.1 Network requirements
The MS/TP network must be inside the building.
The cables must never leave the building.
BACnet MS/TP networks for Desigo TRA can only be wired in line topology.
T-taps (T-junctions) are not allowed, except for stubs (max. 30 m).
Whereas HVAC functions are not time-critical, lighting and blinds require a visible
response within 0.25 s.
For response time reasons, and because the number of commandable group
objects is limited, DXR2.M... room automation stations with MS/TP communi-
cations are subject to the following restrictions:
– Switches / pushbuttons and actuators for Lighting and blinds must operate on
KNX PL-Link, and they must be connected to the same DXR2.M.. .
– No combination with PXC3 (via MS TP to IP router).
As a consequence, no combination with DALI lighting control via a PXC3.
– Room-segment relations only allowed in the same MS/TP network.
– Grouping of several room segments is only allowed for HVAC functions.
The maximum of 32 DXRs can be used as follows:
2 rooms with 16 segments each or 16 rooms with 2 segments each
or any intermediate values.
– If lighting and/or blinds are present, only one DXR2.M... room automation station
per room is allowed.
– No central functions.
– No KNX S-Mode device integration, only KNX PL-Link.
– Connecting the room automation stations to a management station via an
MS/TP to IP router is admitted.
Topology
Restrictions for
DXR2.M...
