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Once most people see the facts they agree that a move from 0-10 V to DALI over time is enviable. But, there is one more factor. A major change is happening in our industry that we feel will be a catalyst and it will drive an almost immediate change to DALI. We will be demonstrating this “catalyst” at LightFair.
A comparison of DALI and 0-10 V Dimming
0-10 V is NOT a standard
There is no set standard between manufacturers on what 0-10 V means. The scale can vary greatly from one driver manufacturer to another. So, if you have two fixtures with the exact same characteristics with the only difference being that the drivers are from different manufacturers, there is almost a 100% chance that they will dim to different rates when given the same 0-10 V command.
With DALI the fixtures are sent the exact same, digital command. If a command is sent to the fixture to dim to 25%, all of the fixtures that receive the command will dim to exactly 25% of their lumen output, regardless of the manufacturer.
One Way Communication
A 0-10 V driver can only receive commands. Unless you are looking at the fixture being controlled there is no way to know if that command was received or if the command was executed. If the fixture has malfunctioned or has been damaged, the only way to tell is to visibly inspect the fixture.
DALI uses two way communication. After sending a command to a DALI driver, the driver will first acknowledge that that command was received and the confirm that the command was executed. A DALI driver can also be programmed to alert you if there is a failure.
Ease of installation
With 0-10v you use two wires and you daisy-chain those wires from fixture to fixture. All of the fixtures in a room or group have to be wired together. You typically use a purple and gray wire and you MUST land the same color wire on the same terminal on every fixture in the group! If the wires are crossed on even one fixture, the group will not work, and you will have to get back up on a ladder of lift and check each and every fixture to find the mistake.
DALI also allows you to daisy-chain just two wires from fixture to fixture, but unlike 0-10 V with DALI you can land either wire on either terminal, eliminating the potential for mistakes.
DALI drivers/systems are much more expensive - MYTH
MYTH Busted!
A DALI system almost always cost less than a 0-10 V system. Let’s look at the facts.
EVERY major (and most minor) driver manufacturers make both a 0-10 V and DALI version of all of their drivers. These drivers typically are made in the same factory and the component difference is so small there is almost know difference in the cost to manufacture.
If there is a cost difference, it is due to the transportation of the driver, not because DALI is more expensive to produce. One of the biggest myths is what the typical cost difference is. I commonly hear anything from $20 to $30 difference per driver! But after a recent survey of 3 driver manufacturers (Fulham, Meanwell & Harvard), the average difference was around $7.
So, you ask how is DALI cheaper if you just admitted that there can be a price difference on the drivers? With DALI it’s all about the installed cost. For example if you have 6 rooms to dim, with 0-10 V you’ll need 6 individual 0-10 V output devices and you have to pull the two wires from each device to the room to be controlled. With DALI you only need one output (for up to 64 fixtures to be controlled) and a single pair of wires that you daisy-chain in the easiest order between all of the fixtures. Because DALI is digital you can group the fixtures via programming not hard wire. So with DALI there is a significant savings when it comes to control devices and wiring not to mention labor. Now factor in places like the City of Chicago where all the wiring has to be in conduit!
Performance Issues
A 0-10 V signal is just a voltage change from 0 to 10 V. But like any voltage signal it is subject to voltage drop. So if you have a long row of fixture like in a corridor that are all connected to the same 0-10 V output the first fixture and the last fixture will dim to different levels. This is a very perceivable difference!
Multiple Networks
On a 0-10 V system the 2 wires are only used to send the dimming command. All other devices like relays, switches, sensors, etc. have to be wired separately. With DALI the two wires can be used to network all of the fixtures as well as the system components.
Additional advantages over 0-10 V
Simple wiring of control lines (no group formation, no polarity)
Control of individual units (individual addressing) or groups (group addressing) is possible
A simultaneous control of all units is possible at any time (built-in initial operation function) through broadcast addressing)
No interference of data communication is to be expected due to the simple data structure
Running power and signal in the same conduit is allowed
Control device status messages (lamp fault, ....), (report options: all / by group / by unit)
Automatic search of control devices
Logarithmic dimming behavior – matching the eye’s sensitivity
System with assigned intelligence (every unit contains among other things the following data:
individual address, group assignment, lighting scene values, fading time, ....)
Operational tolerances of lamps can be stored as default values (for example for the purpose of
energy savings maximum values can be set).
Fading: adjustment of dimming speed
Identification of unit type
Options for emergency lighting can be chosen (selection of specific ballasts, dimming level)
No need to switch on/off the external relay for the mains voltage (this is done by internal
electronic components)
For additional information on this subject:Article Digital and Open - DALI vs. 0-10 V
Power Point Presentation The move from analog dimming to digital dimming
We hope to see you there and let you experience it firsthand at booth #435
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