Installation Instructions

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Siemens Desigo Room automation - Engineering, mounting and installation CM111043en_14
Smart Infrastructure Wiring of power lines 2020-10-30
6.3.2 DXR2 / DXR1
· Topology: DXR2... room automation stations with AC 24 V supply can only be
wired in star topology or with stubs (no daisy chain wiring).
· DXR2.E... / DXR1.E… : AC 24 V grounded or not grounded
· DXR2.M... / DXR1.M… : AC 24 V ^ must always be earthed at the transformer.
· Consumption: DXR2... room automation stations with AC 24 V supply are
limited to a consumption of 4 A / 100 VA.
· The devices have an internal 4 A fuse which CANNOT be replaced.
· An external power supply for field devices should be fused separately for
secure operation. It must NOT be grounded.
The external power supply must NOT be used to supply the triacs.
IEC installation (International Electrotechnical Commission / International Installation Standards)
SELV / PELV
Class II
Transformer with unlimited
power
The over-current protective
device limits the energy in the
secondary circuit.
DXR1.M… : SELV or PELV. DXR2.M...: PELV only!
^ must always be grounded at the transformer.
NEC Class 2 installation (National Electric Code for North America)
A
Using an energy limited
transformer with max. 100 VA
DXRx.
M
...: ^ must always be
grounded
at the transformer.
B
Using a non energy limiting
transformer (max. 400VA)
The over-current protective
devices (T 4 A fuses) limit the
energy to 100VA or less.
Multiple fuses per transformer
may be used to provide
multiple isolated secondary
circuits.
DXRx.
M
...: ^ must always be
grounded
at the transformer.