Gira DALI Gateway Product Documentation page 67

The characteristic dimming curve shown in figure 18 is logarithmic – as it is common in a DALI system.
Thus, the brightness behaviour of the DALI lights during the dimming will adjust to the sense of
brightness of the human eye. The DALI Gateway automatically converts the linear dimming progress in
the KNX/EIB into a logarithmic one (0 / 0 % ... 255 / 100 %). A value feedback to the KNX/EIB will also
be converted. This means that the internal calculation process may result in slight differences between
the brightness value that is specified and the brightness value that is returned (e.g. specification = 50%
-> returned = 49 %)!
Setting the dimming time for relative dimming
The dimming time for the relative dimming can be separately set for each group in the plug-in of the
DALI Gateway.
Set the "Time for relative dimming (0...100 %)" parameter in the "Groups - [x] group name - dimming"
parameter node to the desired dimming time.
Setting the dimming response for absolute dimming
The dimming response for the absolute dimming can be separately set for each group in the plug-in of
the DALI Gateway via the "Brightness value" object.
Set the "Dimming response to a brightness value" parameter in the "Groups - [x] group name -
dimming" to „Dim".
A new brightness value received will be set for the absolute dimming according to the computed
dimming increments.
Set the "Dimming response to a brightness value" parameter in the "Groups - [x] group name -
dimming" to „Jump to".
As soon as a new brightness value is received it will be instantly jumped to.
In addition, it is also possible to set brightness values via a disable or forced-control position
function. An absolute dimming can be activated by providing brightness values even in case of bus
voltage failure or bus/ mains voltage return or after programming with the ETS. In case of these
absolute dimming functions the brightness values will always be instantly jumped to. In case of a
scene recall the dimming response can be configured separately (cf. 4.2.4.5 "Scene function")
Setting the dimming time for absolute dimming
The dimming time for the absolute dimming can be separately set for each group in the plug-in of the
DALI Gateway via the "Brightness value" object.
The dimming response must be parameterized to "Dim".
Set the "Time for absolute dimming (0...100 %)" parameter in the "Groups - [x] group name -
dimming" parameter node to the desired dimming time.
Best. Nr. 1060 00
"DALI Gateway C00CX2 EN / C00CX4 EN" software
Functional description
Page 67 of 136