Siemens Desigo TRA Mounting And Installation Manual page 26

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Siemens
Building Technologies
• The supply wire (AC 24 V) and return lines (⊥) can each have the indicated
lengths.
• Power is added together for multiple back-to-back looped stations which reduces
the cable length accordingly.
• Each supply point (room automation stations/power module/bus interface
module) is either connected separately to the transformer's terminal block (star
wiring) or looped via the room automation station.
• Cables may be wired in parallel to increase the cross section.
• In practice, the small level of permissible voltage drop off means that the
transformer must always be installed in close proximity to the consumers
and that any cascading powering of room automation stations is only
possible over short distances or at small outputs.
Mounting and installation
Wiring for AC 24 V and island bus
CM111043en_03
2013-02-23