ABB i-bus KNX Product Manual page 150

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ABB i-bus KNX
Planning and Application
A KNX value [%]
B KNX value
C DALI value
D Luminous flux [%]
KNX status brightness
E
value
The table assumes ideal DALI equipment (DALI dimming range 0.1...100 %) and in the DGN/S a KNX
dimming range of 0.4...100 %.
Row A and B are the brightness value of the DGN/S received via the KNX as a digital figure value
(0...255) or in % (0...100). This value is implemented by the DGN/S on the DALI (row C). It results in the
luminous flux, which is emitted by the lighting equipment via the DALI characteristic (row D). The DGN/S
then sends the status of the brightness value (row E) back on the KNX.
The dimmable range printed on the ballast relates to the luminous flux. Typical specifications are 3 % or
0.2 %, which due to the logarithmic nature of the DALI curve, are the KNX values of 49 % (126) or 10 %
(26).
The maximum possible dimming range can only be set with DALI equipment, which has a dimming range
up to 0.1 % (KNX value 1 or 100/255 % = 0.4 %). Other DALI equipment has a limited dimming range. This
value is a physical property of the ballast and cannot be changed. This dimming limit has nothing to do
with the minimum dimming value parameterised in the application.
As an example, in the following, DALI equipment with a minimum physical luminous flux of 3 % can be ob-
served. In the KNX, a dimming range of 126...254 is thus available. This means, the lowest brightness va-
lue that can be set and fed back on the KNX is 126 or 50 %. KNX values, which are less than 126 or 50 %,
are set by the DALI equipment to the threshold value and fed back by the DGN/S on the KNX.
A KNX value [%]
B KNX value
C DALI value
D Luminous flux [%]
KNX status brightness
E
value
The characteristic curve described in the following section is represented as the usable range of the ballast
with the control value range for the brightness value on the KNX. In this way, a higher resolution of the
brightness values on the KNX is possible. However, nothing changes in the physical threshold values of
the ballast and the light yield.
148 2CDC 507 114 D0201 | DGN/S 1.16.1
0 0.4 24 33 49 57 67
0 1 60 85 126 144 170 195 210 220 229 235 241 246 250 255
0 1 60 85 126 144 170 195 210 220 229 235 241 246 250 254
0 0.1 0.5 1 3 5 10
0 1 60 85 126 144 170 195 210 220 229 235 241 246 250 255
0 0.4 3 10 24 33
0 1 8 26 60 85
0 1 8 26 60 85
0 3 3 3 3
12 12
0 126 126 126
6 6
77 82 86 90 92 95
20 30 40 50 60 70
49 57 90 92 95
126 144 229 235 241
126 144 229 235 241
3 3 5 50 60 70
126 144 229 235 241
97 98 100
80 90 100
97 98 100
246 250 255
246 250 254
80 90 100
246 250 255