Technical information
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Dimming
DALI
As standard, Fagerhult have chosen to supply all luminaires
with Helvar’s DALI-ballasts with an integral power supply. This is to
enable a system with a central DALI power supply to incorporate
luminaires with dierent brands of DALI-ballasts.
However, luminaires without an integral power supply are avail-
able on request.
DALI (Digital Addressable Light-
ing Interface) is a standardised
digital protocol for dimming.
DALI is supported by the major
manufacturers of HF-ballasts in
Europe (Helvar, Osram, Philips
and Tridonic). Other companies
within the lighting industry
have also joined the group of
DALI-manufacturers.
DALI uses a single multi-core cable through which a duplex digital
signal is transferred between all units in the system. Connected
HF-ballasts, control panels, sensors and the programming units
communicate with each other. The “intelligence” is distributed,
(read stored) in the system’s dierent component parts. This creates
greater safety and reliability as the system is not dependent on any
central unit.
The DALI-system is also very flexible and future-proof as any
change to the design of the premises or usage, results only in the
need to reprogram the settings. Generally the cabling does not need
to be changed.
In the DALI-system information is transferred between com-
ponents via an addressed digital signal. As the signal is digital all
included luminaires are controlled in exactly the same way, irrespec-
tive of the distance between the control unit and luminaire. The
HF-ballasts used in DALI are adapted to the sensitivity of the eye for
light level adjustments, a.k.a. logarithmic compensation.
Apart from the phase, neutral and earth conductors, two other
wires for the digital signal are connected to the luminaire. These
cables are polarity free which simplifies installation.
The digital control signal is also insensitive to external distur-
bances. The lighting is switched on and o by means of a digital
command via the DALI-conductors. It is therefore beneficial to con-
nect the mains voltage directly from the fuse panel to the luminaire.
Combining DALI with other control systems
DALI can easily be combined with other control systems such as
analogue 1–10 V. When there is no need to control or monitor an
individual luminaire, or when existing rows of luminaires are to be
incorporated into the new control system, it may be possible to use,
for example, a DALI to 1–10 V interface (converter). The existing
luminaires, equipped with HF-ballasts for analogue 1–10 V dim-
ming, are connected to a DALI to 1–10 V interface. Using this solu-
tion the luminaires can be controlled centrally via DALI-panels for
example. The solution is more economical and it also significantly
increases the number of luminaires that can be controlled in a
DALI-installation. This is because a single DALI address now controls
several luminaires. The same solution can be used with luminaires
equipped with HF-ballasts for DSI dimming, with the help of a DALI
to DSI interface.
Helvar have chosen a solution where, via the HF-ballast, you have
the possibility to supply power to the DALI-system. The use of this
function however, requires the total current in the control cables
to be calculated, with regard to all the components included in the
system.
Advantages of the DALI-technology
Addressability. Possibility to individually control dierent luminaires/HF-ballasts in •
the same system. Max 64 addresses/system.
Light scenes and groupings. Possible to pre-program dierent light scenes. Up to •
16 groups of luminaires and 16 dierent light scenes can be created in each system.
Ignition and extinguishing of luminaires takes place via digital commands. •
Control conductors for the digital signals have no polarity (positive/negative), which •
reduces the risk of incorrect connection.
The digital control signal is not sensitive to disturbances transferred from other •
conductors. The control conductor can be routed together with the main voltage
conductors without the risk of disturbances (note however that the control conduc-
tors should also be of a heavy current type).
Duplex communications via the control conductors is possible. Status and any error •
indications from components in the system can be gathered by any connected
software.
The control signal is transferred in the same way to all luminaires independent of •
the control conductors’ length.
Digital technology also allows the system to be controlled via computers. •
DALI can also be integrated with a BMS system (for example, LonWorks). •
Multiple DALI systems can be controlled over routers connected to an Ethernet •
network.
Note
Programming is carried out using wall panels, remote control units or with the •
help of computers and software. The use of software is recommended for all large
installations.
DALI requires the control circuit to be fed with a current. This current may be •
max 250 mA, which is obtained by means of an external DALI power source. A
high current in the circuit results in a communications breakdown or damaged
components. Consequently, it is important that a DALI-system is planned and
dimensioned correctly.
Maximum cable length for the control circuit is 300 m.•
The characteristics of the units from dierent manufacturers deviate slightly.•
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