ABB i-bus KNX Product Manual page 18

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ABB i-bus KNX
Device technology
Note
When positioning the Light Sensor LF/U in the room, it is important to ensure that the individual control
circuits cannot interfere with one another. The LF/U should be mounted above the area, in which the
actual lighting intensity is measured.
The luminaires or sunlight may not shine directly into the brightness sensor. Pay attention to
unfavorable reflections, for example, from mirrored or glass surfaces.
The white fibre-optic rod can limit the detection range and reduce the lateral lighting sensitivity to
external lighting sources.
Note
If the LF/U is not connected to the DLR/S, a DC voltage of a few mV can be measured directly with a
multi-function measurement device. The measured value is between 0 mV (absolute darkness) and a
few 100 mV, depending on the brightness. If 0 mV is also measured at normal brightness, this is due to
an open circuit, short circuit or inverse polarity fault or a defective sensor.
16 2CDC 507 100 D0202 | DLR/S 8.16.1M