Siemens 5TC1 Series Bedien-Und Montageanleitung Seite 58

The immunity to false light is ensured by a time delay.
During transition from bright to dark, the ambient brightness
must be at least 10 seconds below the preset brightness level
before detected movements trigger a switching action.
The same applies to the transition from dark to bright. Only if the
preset brightness has been exceeded for at least 10 seconds,
will detected movements no longer trigger a switching action.
Exception: The 10 s delay is not available if the motion detector
attachment 'Komfort' has just switched off.
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