Measurement of illuminance of interior lighting system automatically dimmed to the constant level depending on daylight

The article describes verifying of behaviour of dimming in a regulated lighting system in Smart Home (SH) which was controlled to the constant level of illuminance. The proposed method of measuring was realized as an upgrade for evaluation of curves of interior illuminance caused by daylight. A reference room in SH with a measuring device evaluating illuminance in the places of visual tasks and at the same time scanning illuminance caused by daylight on an outdoor unshadowed horizontal plane was used for measuring. The used measuring device was supplied with a dimmable lighting system of artificial lighting using luminance controller situated on the ceiling of the room in combination with controlling system KNX to reach the constant level of illuminance regarding the influence of both elements of artificial light and daylight. The article shows that there might be difference between the set value of illuminance, which is regulated by a KNX system, and real illuminance in the place of a visual task. Due to this difference, the lighting system may not meet the normative requirements, which is absolutely inacceptable.