The CD-IR28B is an active infra-red motion detector. It senses changes in heat via its Fresnel lens to detect human movement. The sensor detects even the slightest movement in the detection zone. The unit is designed to be fitted onto ceilings and walls. 360° sensing is assured via its three heat sensors. A 30 Amp relay enables the switching of many fittings from one sensor. A long (30 minutes) maximum time setting will reduce the possibility of the lights being extinguished when somebody is present. A built-in light sensor facilitates daylight harvesting.