General Information About The Bus System; General Information On The Installation; Topology Of The Bus System; Installation - HomeMatic HMW-LGW-O-DR-GS-EU Installation And Operating Manual

5 General information about the
bus system

5.1 General information on the installation

When connecting the RS485 bus, the A terminals
(1.3), the B terminals (1.7), the 24 V power supply and
the ground terminal (1.8) of the modules of a sub-
distribution (max. 127 segments) are to be connected
with one another. A bus terminator is always required
for this installation.

5.2 Topology of the bus system

The HomeMatic Wired components should always be
mounted in groups of sub-divisions to provide a better
overview. The number of sub-divisions that is appropri-
ate depends on the type and size of the project and is
to be defined accordingly. Installing at least one sub-
division on each level is recommended. Larger buil-
dings may require planning several sub-divisions per
level (e.g. separate for every floor). Bus cabling and a
ground cable have to be installed between the distribu-
tors. All load and control wiring should also be run in a
star format to the respective sub-divisions.
The power is supplied via a 24V DIN rail power supply
unit (24V V power supply with stabilized output vol-
DC
tage) according to the number and total current con-
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sumption of all existing modules. You will find further
details regarding the power consumption of the single
devices in the corresponding operating manual.
6

Installation

Observe the installation instructions for installa-
tions in distribution systems (DIN VDE 0100-
410).
Only to be installed by persons with the
relevant electro-technical knowledge and
experience.
Contact an electrical installer!
Specialist knowledge required for installation:
The following specialist knowledge is particularly im-
portant during installation:
• The ‚5 safety rules' to be used:
- Disconnect from mains;
- Safeguard from switching on again;
- Check that system is de-energised;
- Earth and short circuit;
- Cover or cordon off neighbouring live parts;
• Select suitable tool, measuring equipment and, if
necessary, personal safety equipment;
• Evaluation of measuring results;
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