RapidLED programming issue

Ok, so I got my setup and am ready to start programming my automation system for my aquarium. To test everything, I just used the fade program from the example list and followed the range from 0 to 255. The lights dimmed, but they cut off completely at 32 and are no where near dim at all. Any insight on this? I'm using the following wiring:

Thanks in advance!

And your code is? (Please use code tags).

How to use this forum

I do rather suspect that "dimmable driver" of yours - itself a switchmode device - expects a chopped sine wave which reduces in voltage at lower dimming levels, rather than very short pulse widths.

I just looked up the instruction manual for you!

You are using - according to your diagram - an ELN-60-48D which is a voltage control, not the ELN-60-48P which is a PWM control.

You would need to add an integrator to convert your PWM to voltage - try a 1K resistor in series and a 22µF capacitor across the control input. You may need to know the input impedance of the control input by feeding it with 10V through a milliammeter; if it is greater than 22k? (0.45 mA), you may want a resistor of that value across the capacitor.

Sorry, I should clarify a few things as some of you have pointed out. I'm not using the 48D, I'm actually using the ELN-60-27P

The code I'm using is

/*
 Fade

 This example shows how to fade an LED on pin 9
 using the analogWrite() function.

 This example code is in the public domain.
 */

int led = 9;           // the pin that the LED is attached to
int brightness = 0;    // how bright the LED is
int fadeAmount = 5;    // how many points to fade the LED by

// the setup routine runs once when you press reset:
void setup()  { 
  // declare pin 9 to be an output:
  pinMode(led, OUTPUT);
} 

// the loop routine runs over and over again forever:
void loop()  { 
  // set the brightness of pin 9:
  analogWrite(led, brightness);    

  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;

  // reverse the direction of the fading at the ends of the fade: 
  if (brightness == 0 || brightness == 255) {
    fadeAmount = -fadeAmount ; 
  }     
  // wait for 30 milliseconds to see the dimming effect    
  delay(30);                            
}

I've tried adding a resistor between the red and black cable from the driver to the LEDs, and they get down to pretty low levels, but they won't dim at that point. I don't believe there's a cut off, they're suppose to range 0-2.3A according to their description on the website.

http://www.rapidled.com/mean-well-eln-60-27p-dimmable-driver/

I found the driver specs from their website:

http://www.meanwell.com/search/eln-60/default.htm

So apparently it says the cutoff is at 15% I'm not much of an electrician, obviously still learning, but the range for PWM is 0-255, and 15% of that is ~38 so it cutting off when I hit 32 seems correct, but it's still blindingly bright. When I stick a resistor between driver and the LEDs, they get so much dimmer, (can get them to where I want) but then they won't dim.

Endevor: I'm not much of an electrician, obviously still learning, but the range for PWM is 0-255, and 15% of that is ~38 so it cutting off when I hit 32 seems correct, but it's still blindingly bright. When I stick a resistor between driver and the LEDs, they get so much dimmer, (can get them to where I want) but then they won't dim.

An unfortunate and well-known limitation of the Meanwell driver. Consider a Luxdrive BuckPuck instead?

[/quote]An unfortunate and well-known limitation of the Meanwell driver. Consider a Luxdrive BuckPuck instead? [/quote]

Any idea which model I should get?

How many LEDs in each series-string? And what's the max power level you want to drive the LEDs at?

Each string holds 6 leds. I'm not fully sure how much power I want to shove through.

Max current for the LEDs I have are 1000mah

Ok, then one 1 amp 3021/3023 BuckPuck per string should work. Figure 14 on the datasheet shows PWM dimming from something like an Arduino.

The thing about BuckPucks is they don’t just plug in to wall power. You’ll need a 24V or higher power supply of some kind, with enough amperage to drive all the BuckPucks you have (or multiple power supplies). Let me know if you want a PM on where to get such inexpensively.

Looks like BuckPucks accept PWM up to 10kHz, but the Arduino defaults to only 1kHz. You may get better results in the near-zero zone by using pin 5/6 with the PWM divisor set to 8 to get 7.8kHz (http://playground.arduino.cc/Main/TimerPWMCheatsheet).

Sadly the Meanwell tops out at 3kHz so playing with the frequency probably isn’t going to help there.

Endevor: When I stick a resistor between driver and the LEDs, they get so much dimmer, (can get them to where I want) but then they won't dim.

Of course not!

You cannot have it both ways.

The driver you are using is a constant-current driver; it controls the current according to the dimming input and the "limit" potentiometer. It will do its absolute best to overcome any resistance you add in circuit; either it will deliver the current it is set to, or as the resistance is higher, it will go to maximum voltage and the resistor will limit the current to a constant (dim) value.

Thanks, I'll try the buckpuck. Does it have a cutoff? Or does it fade to off?

I run a BuckPuck on my reef, but I'm using an analog pot rather than PWM so I don't have firsthand experience. However if you do some web searches you'll find references to BuckPucks dimming to 0 like:

http://www.ultimatereef.net/forums/archive/index.php/t-388233.html

Awesome! I just ordered 3 of these and I'll see how they work (1A).

http://www.superbrightleds.com/moreinfo/component-leds/led-driver-buckpuck-dc-external-dimming-constant-current/1050/

Thanks for the link. I've never heard of buckpuck before, but I wish I had before I dropped 30$ for those meanwells. Now that I've heard of them, I'm finding several people doing projects with them and even have some wiring schematics, so hopefully they'll work.

I got it to work with one buckpuck and a string of 3 leds. Each LED I have uses 3V, therefore I needed a 9V power supply attached to the buckpuck. My heatsink can hold up to 24 LEDs, each at 3V making the need for power at 72V. I don't know if they even make power supplies that big, but if they did, and I wanted to split that voltage among 8 different buckpucks, how would I go about doing that?

White and blue LEDs are typically 3.6V, so you'd probably want a 12V supply for three-in-a-string or 24V for six-in-a-string. (Red LEDs are around 1.8V.)

You can do any combination of series and parallel that suits. The LEDs go in series and the BuckPucks go in parallel.

If you have four 2A 12V supplies, use 8 BuckPucks with two paralleled on each supply, LEDs 3-in-a-string.

If you have two 4A 12V supplies, use 8 BuckPucks with four paralleled on each supply, LEDs 3-in-a-string.

If you get one 4A 24V supply you could run 4 BuckPucks all paralleled with LEDs 6-in-a-string.

If you get two 2A 24V supplies you could run 4 BuckPucks with two paralleled on each supply and LEDs 6-in-a-string.

I can send you a link to inexpensive 24A supplies if you like?

tylernt: If you have four 2A 12V supplies, use 8 BuckPucks with two paralleled on each supply, LEDs 3-in-a-string.

If you have two 4A 12V supplies, use 8 BuckPucks with four paralleled on each supply, LEDs 3-in-a-string.

I think one of those would be the best route. A link would be awesome for some cheap power supplies. The less I have to run to radioshack, the better. I'm still new to electronics, but I have heard of running in parallel. I've never done it before however, at least not with anything more complicated than just simple resisters. How would I do that with buckpucks? (I have the 3023-D-E-1000 models) And also, I currently only have 3. Would I be able to set it up so I can simply plug in more as I expand my project? I plan to only do it in strings of 3.

Thanks

For BuckPucks in parallel, just put all of the Vin + together and all of the Vout - together. You can parallel as many as you like as long as you don't exceed the amperage of your supply (three Buckpucks on a 3A supply for example).