HomeMatic HMW-IO-12-Sw7-DR Installations- Und Bedienungsanleitung Seite 31

sure that the connections are made with correct
polarity on the terminals.
Note that actual buttons (normally open) and
no rocker switches or push-button switches
are used in the button input circuits. Connect each
of the buttons between GND (terminal 1.8) and the
respective button input (terminal S1, ...).
The maximum wire length from button to
module is different depending on the wire
used. A length of 50 m should never be exceeded
however.
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