Presence detection

When using presence detection for lighting control, there are two basic initial statuses that need to be distinguished: Presence status and absence status.

  • Typical motion detectors (see footnote) installed on buildings are tasked with registering approaching persons reliably and switching on the light. Where they are installed on front doors, they are usually intended to keep the light switched on for as long as the person lingers in the entrance area. The aim is to provide protection against break-ins and accident risks by avoiding darkness.

  • In contrast, an indoor light management system’s presence detection facility has the (main) task of reliably turning off the light once no more persons are present in the room – and only then. Inasmuch, one could also call this feature "absence detection". Energy is only saved in cases of absence, which is the installation’s intended purpose (see also chapter 1.3.5.5 "Light and the environment").

In the following, the indoor purpose – meaning "absence detection" – and its many implementation constellations are addressed.

The widespread distinction between motion detection and presence detection will not be considered here, since both terms refer to individually installable functional units with different ranges of function (whereby the distinction is not clear). This text is intended to solely address the presence detection function – regardless of the installation device’s range of function.