A KNX presence detector configured with a 15-minute timeout keeps the lighting on for that duration after the last detection, then automatically switches it off.

Off-delay values typically range from 5 to 30 minutes depending on usage: around 15 minutes for offices, 3 minutes for corridors, 5 minutes for restrooms. The detector sends DPT 1.001 = 1 on detection and DPT 1.001 = 0 once the off-delay elapses. It is commonly combined with a lux sensor so the light is not switched on when daylight is already sufficient.

Choose the off-delay based on typical absence patterns (toilet break, meeting room turnover) — too short causes nuisance switching, too long defeats the energy purpose.