Theben DU 1 Manual page 81

8.5.2 The parameters: Switching on/off with a 4-bit telegram
In general, the setting yes is required.
The setting no is available for use with special customer requests, e.g. in conference rooms.
The situation is described as follows:
A whole group of dimmer channels is operated from a button (4-bit).
A certain lighting situation has been set by a scene or other means – e.g. channel 1 OFF,
channel 2 40%, channel 3 50%. The requirement is to now dim up and increase the brightness
of the entire scene, but the channels which are switched OFF should remain off.
The parameters Switching on/off with a 4-bit telegram block the usual
switch on/off function of the 4-bit telegram.
Parameter Switch-on
with 4-bit telegram
yes
no
Parameter Switching
off with a 4-bit
telegram
yes
no
Flush-mounted dimming actuator DU 1
4-bit Dimmer output
Telegram status
brighter/darker Switched on
(1%...100%)
brighter Off
brighter Off
brighter/darker Switched on
(1%...100%)
4-bit Dimmer
Telegram output status
brighter/darker Switched on
(1%...100%)
darker On
darker On
brighter / darker Switched on
(1%...100%)
Response
Channel is normally dimmed.
Channel is switched on and
dimmed brighter
Dimmer stays switched off
Channel is normally dimmed.
Response
Channel is normally dimmed.
The channel is switched off if the
button is kept depressed for
longer than approx. 2 s when the
minimum brightness is reached.
Channel can be dimmed down to
the minimum brightness, but is
not switched off.
Channel is dimmed in range from
min. to 100% and remains
switched on.