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Dimmable LED Drivers
Dimmable
LED Drivers
LED light regulation systems
Analog systems 1÷10V and 0÷10V
The regulation takes place via a low voltage analog signal according to the EN 60929 E standard.
With a variable voltage from 0 to 10V the power supply regulates the output load with a PWM signal from 10% to 100%. The curve is linear.
Each device on the line supplies a current to the regulation terminals to allow passive control by means of a potentiometer.
The potentiometer can be linear or logarithmic to change the adjustment curve. In the case of multiple devices connected together on
the same line, an external regulator powers all the devices passively, up to approximately 5 power supplies, or actively, for more complex
systems.
The difference between the two systems is in the behavior when the regulation is at minimum, the 0÷10V system turns off the appliance if
the line drops below 1V, while in the 1÷10V system the appliance remains on at minimum.
In the 0÷10V case, the command itself is used to turn off the appliance, while in the 1÷10V case, a command on the power circuit is used
to turn off the appliance.
All devices on the line behave the same way and it is not possible to adjust them individually.
TRIAC, IGBT, Mosfet
The regulation is carried out with a specific power supply that controls the load.
The power supply is partialized by the dimmer connected on the primary side; depending on the dimmer control system, the supply
voltage is partialized with different systems but always interrupting the voltage for variable periods on the primary.
This type of regulation is quite imprecise due to the multiplicity of devices available on the market and the minimum light level never drops
to very low levels so as not to create instability in the system.
It is always recommended to use regulators with adjustable minimum level and compatible with the LED load.
The system is very simple to create and does not require particular technical knowledge other than the control of the components which
must all be compatible with this type of regulation. LED bulbs or LED load, the power supply and the dimmer or regulator must indicate
the LED load or TRIAC IGBT regulation.
DALI Digital Addressable Lighting Interface
DALI is a digital protocol that allows the regulation of devices equipped with this system.
The protocol is regulated and standardized according to EN 62386 with different requirements 101,102,207,209 depending on the use.
The information on the DALI line allows multiple devices to be controlled independently and complex controls can be created. Each device
is addressed with a unique code. In addition to receiving commands, each device can in turn transmit information to the control system
(Master) about faults, confirmations on commands received, working hours, alarms, etc. etc.
The DALI system has been perfected over the years, moving from DALI1 to DALI2 and developing different codes to control DT6 white light
or DT8 colored light devices.
A DALI system includes a MASTER that sends commands to the devices (Max 64) and a power supply for the low voltage DALI line. In more
complex systems there may be multiple Master control devices
The DALI line is not polarized and the cables can be very long.
The devices are addressed and created groups through software during the creation of the system.
The DT6 system requires that each device is assigned an address, which is used for the white light, adjustable in 256 levels.
The DT8 system allows you to use devices with two or more channels using a single address so the signal will be simplified and faster in
the execution of commands. DT8 is a specific system for controlling two-channel "Tunable White" systems or RGB or RGBW systems ( three
and four channels ). In particular, to regulate colored light, the DT8 system provides different systems based on chromatic coordinates or
RGBWAF color, the latter chosen by QLT for its devices.
Push button adjustment
The simplest system for regulating a light fixture is with a push-button; now, in common knowledge, everyone knows that pressing the
push-button turns on the light and holding down regulates the light.
It is a simple and effective system for private homes and very economical; multiple push-buttons on the same line can create relatively
complex and easy to manage systems.
The push-button line must be mains voltage, in fact the control cables run together with the power cables and therefore must be immune
to interference for long distances.
In the case of low voltage push-button controls, they are suitable for installations in humid places such as bathrooms, showers, etc.. if they
are used in common with high voltage cables, double insulation connections and reduced lengths must be used due to of possible signal
interference.
Normally the push-button line is in common with the DALI line because by its nature the DALI line is isolated from the rest of the system
and can work at high voltage without problems, therefore the two systems coexist on the same control line but only as an alternative to
each other, not in common. Even complex devices such as WIFI or BLE systems have an input for a push-button, to always be able to control
the light in the event of a power failure or as an auxiliary control.
DMX 512
Low voltage digital dimming system used primarily for color dimming, created in 1986 and later updated by USITT (United States Institute
for Theater Technology). The Master sends a signal to devices addressed according to an open system, without receiving a response. The
addresses are set in hexadecimal code through DIP SWITCHES during installation. The command sent reaches the device, which executes
it without carrying out any checks. The low voltage DMX control line is made up of a Master, devices and a terminator which keeps the
line at a set impedance, 120 Ohm, to avoid interference. The line is polarized. The system used for transmission is the common industrial
monodirectional RS485.
This system is very fast and suitable for lighting effects such as use in theatres, discos etc. The system is not commonly used in white light
control.
