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Thema: Problems dimming lower than 7%

  1. #31
    Registriert seit
    02.01.2012
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    Warsaw
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    123

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    it's not impossible.

    Inside my drivers I don't have any additional V+.
    Look on driver schema ( it's only 1 channel, I've made a 4 channels drivers where all PWM pin are connected together ):

    MBI6651-drv.png

  2. #32
    Registriert seit
    06.02.2012
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    2.020

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    it's not impossible.


    Inside my drivers I don't have any additional V+.
    There is a +24V

  3. #33
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    14.12.2012
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    54

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    Zitat Zitat von bjomat Beitrag anzeigen
    If I want to change drivers to run my leds. Any suggestions to use with ghl LEDcontrol4passive. I use two channels running 28x3w leds on each channel.
    Anhang 3555
    My day off working with the aquarium leds/profilux/LEDcontrol4passive ended with a destroyed driver. I ordered a new one which I expect will arrive this week. I am then going to try again. I really want my leds to be able to dim down to 0% so that I can use my Simu L with sunrise/sunset/thunderstorms.

    Gunther - You put in a nice pic in post 25 about using a resistor between pwm+ and 5V+. Do you really think that could do it? When I tried to connect the LEDcontrol4passive without the resistor I got 0% light only (I couldn´t get the lights to work at all...)

    Regards Björn

  4. #34
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    06.02.2012
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    Gunther - You put in a nice pic in post 25 about using a resistor between pwm+ and 5V+. Do you really think that could do it?
    It should, but find out the right resistor value may be not so easy.

    When I tried to connect the LEDcontrol4passive without the resistor I got 0% light only (I couldn´t get the lights to work at all...)
    That was a very bad idea ......

    If you try it without resistor and no connection between 2+4 nothing will happen for sure and the LEDs will stay dark (that´s what I take from Steve´s manual).

    If you connect 2+4 without resistor and witout LEDControl4Passive the LEDs should have 100% - if not, the driver is propably broken - anyway, disconnect it fast in that case!
    Now you can set LEDControl4Passive to 100% and connect it to 2/4 wire, the LEDs now should also have 100% - if not, the LEDControl4Active is propably broken - anyway, disconnect it fast in that case!

    The resistor only is used to protect the driver´s power supply and the LEDControl4Passive against the +5VDC power source. If you connect 2+4 without resistor to the LEDControl, the driver and/or the LEDControl4Passive may be destroyed due it drops the +5V to ground for dimming. The resulting current without resistor may be much to hight for both devices.
    Geändert von Gunther (12.02.2013 um 11:49 Uhr)

  5. #35
    Registriert seit
    14.12.2012
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    54

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    ImageUploadedByTapatalk1360673181.175052.jpg
    This is the connection I used when the lights didn't work at all (before the driver died)
    Could it be something with the ground (mixing ground 24v- and ground from profilux?)

    Regards Björn

  6. #36
    Registriert seit
    06.02.2012
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    This is the connection I used when the lights didn't work at all
    This cant work (never ever). Connection 4 of the drivers is open, so there is no power for the PWM

    Could it be something with the ground (mixing ground 24v- and ground from profilux?)
    No. The LCD4P has no connected ground on the PWM side. The LCD4P is like an array of switches as shown in the pic below. It has no connection to the 1-10V channel inputs.

    The pic is simplified, but it shows that if you have not connected any power to the circuit, so the input on pin 2 of the driver gets no signal and the LEDs stay off.

    LCD4P.jpg

    What I have done with the resistor in the pic from post #25 is as follows:

    • If the switch of the LCD4P is open, pin 4 and 2 are connected via the resistor and Pin #2 has +5V. In this case the driver will output 100%
    • When the switch of the LCD4P closes, it connects the +5V to ground and the voltage will drop down. The resistor limits the current to protect the 5V power supply and the switch in the LCD4P. If the voltage is 0V, the the driver will output 0% aka it is off.
    • Doing that on/off thing a hundred times a second with various on/off times is called PWM and will dim the LEDs (in fact, it´s on/off switching and not dimming in real, but LEDs are fast enough to have it look like it´s dimmed).

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