ABB i-bus EIB Series Operating Instructions Manual page 26

Product Description
GB
The unit is intended for mounting on solid walls or ceilings.
With its coverage range of 220° the unit also can be used
for the monitoring of adjacent set back facade areas.
The maximum detection reach is approx. 16 m when
approaching the unit diagonally (with a mounting height of
approx.2.5 m). For more information see Section «Coverage
Zone».
The watchdogs are glare-proof, ie if exposed to direct light
(eg from an electric torch/flashlight) the monitoring function
remains active for approx. 1½ minutes.