
DALI MCU
Digital potentiometer 
Fitting instructions
Description
A
Purpose and application
The DALI MCU digital potentiometer controls up to 25 DALI 
electronic control gears and enables the manual operation of 
luminaires with a DALI interface.
The potentiometer is mounted in ush device boxes.
Function
The potentiometer converts rotations of and pressure on the 
rotary knob into DALI commands.
By switching multiple DALI MCU in parallel, the number of control locations or the number of controllable luminaires can be increased. If multiple potentiometers are switched in parallel, the 
commands of the potentiometer actuated last apply. Automatic 
synchronization makes it possible to change the control location 
without disturbing effects (e.g. brightness uctuations).
The DALI MCU can be supplied directly from the DALI control 
line (= passive operation) or can deliver the required control 
current itself when connected to the mains voltage (= active 
operation).
Design
The potentiometer is made up of the following components:
• Rotary potentiometer (A)
• Connections (B)
 – Control line (da+, da–)
 – Neutral conductor (N)
 – Phase (L)
• Housing with rotary knob (C)
C
Installation
B
Safety instructions
The potentiometer must only be installed and put into operation 
by a qualied electrician. The applicable safety regulations and 
accident prevention regulations must be observed.
WARNING!
Exposed, live cables.
Danger of electric shock!
• Only work on the potentiometer when it is de-
energised.
CAUTION!
Destruction of the potentiometer and other devices 
through incorrect mounting!
• The potentiometer is designed for mounting in 
ush device boxes. If mounted elsewhere, provideadequate cable strain relief and insulation.
• Do not wire the control line with an external voltage, especially not a mains voltage of 230 V.
• Do not exceed the maximum number of ECGs 
and total line length.
IV 2009
DALI_MCU_ma0904en_we1.01.indd
OSRAM GmbH 
Kunden Service Center 
Customer-Service-Center (CSC) 
Steinerne Furt 62 
86167 Augsburg 
Germany
Tel : +49 (0) 1803 677 - 200  
(kostenpichtig / charges apply) 
Fax.: +49 (0) 1803 677 - 202
www.osram.com
www.osram.de
40083211897216
4008321189721
Continued on the back page!

Installation (cont.)
Connecting the potentiometer
To control DALI ECGs, a maximum of 4 active potentiometers 
can be connected in parallel.
C
D
• 1 active potentiometer: max. 25 ECGs
• 2 active potentiometers: max. 50 ECGs
• 3 active potentiometers: max. 75 ECGs
• 4 active potentiometers: max. 100 ECGs
C  Active potentiometer (with mains connection)
D  Passive potentiometer (without mains connection)
Appendix
Technical data
Operating voltage 230 V AC, 50-60 Hz
Maximum total length of 
signal line
DALI connection Max. 25 DALI ECG with one 
Maximum power consumption
Permissible line cross 
section
Permissible ambient temperature
300 m
active DALI MCU
3 W
1 – 4 mm²
0 °C to 50 °C
Protection type IP 20
Protection class II
Dimensions Flush-mounted part (Ø x H):  
51 x 32 mm 
Mounting plate (L x W):  
71 x 71 mm
Dimensions
The requirements as per EN 60928 und EN 61547 are fullled.
Conformity with the relevant EU directives is 
conrmed by the CE symbol.