How to dim a Meanwell ELN-60-48D...

[JaredWaites]

My concern with running a 12v supply with just resistors (2K drop resistor and a 10K pot) is that not all 12v wall warts have the same output. Some of the really cheap ones can output voltages as high as 16v with little to no load. Stating that a resistor and a pot can work for any situation is a risky one. Anyone that has worked with electronics long enough will know that those power supplies are all over the place.

While an LM317 isn't the best choice, it's a readily available one for anyone that walks down to the local Radioshack. With a 12v power supply (that usually outputs higher than that anyway), getting 1.25v to 10v output is no problem. Even if you use a regulated 12v supply, with the 2.5v drop off, you can still adjust the driver up to the desired current with SVR2 with the lower 9.5v input. It's still safer than running up to 12v.

I have talked with Meanwell tech reps on this issue and they cannot and will not warranty damages to the driver from input voltages higher than about 10.5v. Because this isn't an inverted input driver like the Buckpucks, if you kill the dimming circuit, you have a useless driver. Spend the extra few dollars to regulate the voltage.

So as long as you know what your wall wart is putting out then you can pair a resistor to make sure suited for that voltage...correct?

 

[evilc66]

That's possible, but the output voltage can change with heat too. It would probably be good to err on the side of caution and drop a little more voltage. A voltage regulator takes away all of these concerns and issues though. It's not like they cost all that much. This way it's the same circuit with the same part values for every power supply instead of trying to figure out custom values for every power supply.

 

[stugray]

evilc66,

"While an LM317 isn't the best choice, it's a readily available one for anyone that walks down to the local Radioshack."

Agreed, and I have a LED light running on my QT with two CREE XR-E using just a LM317 as a driver.

However - you need to install at least two Caps and a variable resistor in the circuit.
This is a little beyond most DIYers ability to solder discrete parts together without a PWB. ( although DWZM could easily do a VERY nice LM317 driver PCB for us ).

Anyway, if the variability of wall warts bothers you, lets say:

Get TWO 5k Pots.
Hook high side of POT 1 to Wallwart ( unknown voltage < 24V )
Hook Wiper of POT 1 to High side of POT 2 ( insulate low side of Pot 1 )

Hook Low side of POT 2 to wall wart ground

Turn on wall wart & measure voltage across POT 2
Adjust POT 1 until max Voltage across POT 2 = 10.0 VDC

Hook wiper of POT 2 to Meanwell Dim+
Hook wall wart Ground(RTN) to Dim-

NOW you can get 0-10V by adjusting POT 2 regardless of voltage of wall wart. ( DO NOT adjust POT 1 ever again )

Sorry if that sounds complicated but it's not.

Stu

 

[evilc66]

Honestly, I think it's more complicated than a simple LM317 regulator circuit, but lets just agree to disagree here.

I do think that anyone who is building a DIY LED array has the capability to assemble a simple circuit. It's not like we are asking them to build an Atmel controller from scratch. It's a few simple discrete components soldered to a perforated breadboard. If you can solder to the pots, you can solder this up.

 

[stugray]

Ok,

"but lets just agree to disagree here."

But 2 POTs vs:

2 Caps
1 POT
1 LM317
1 Perfboard
1 Heatsink for LM317 if supply voltage is much above 10V

Thats two components versus six.


BUT agreed - if you can grasp the variable resistor network concept, then the LM317 is not much more difficult & more reliable in the end.

Stu

 

[evilc66]

Not to bad when you paint by numbers. All of these parts can be bought at Radioshack. This will accept 12-32v and still work perfectly.

 

[JaredWaites]

evilc66,

"While an LM317 isn't the best choice, it's a readily available one for anyone that walks down to the local Radioshack."

Agreed, and I have a LED light running on my QT with two CREE XR-E using just a LM317 as a driver.

However - you need to install at least two Caps and a variable resistor in the circuit.
This is a little beyond most DIYers ability to solder discrete parts together without a PWB. ( although DWZM could easily do a VERY nice LM317 driver PCB for us ).

Anyway, if the variability of wall warts bothers you, lets say:

Get TWO 5k Pots.
Hook high side of POT 1 to Wallwart ( unknown voltage < 24V )
Hook Wiper of POT 1 to High side of POT 2 ( insulate low side of Pot 1 )

Hook Low side of POT 2 to wall wart ground

Turn on wall wart & measure voltage across POT 2
Adjust POT 1 until max Voltage across POT 2 = 10.0 VDC

Hook wiper of POT 2 to Meanwell Dim+
Hook wall wart Ground(RTN) to Dim-

NOW you can get 0-10V by adjusting POT 2 regardless of voltage of wall wart. ( DO NOT adjust POT 1 ever again )

Sorry if that sounds complicated but it's not.

Stu

Heck I don't know why...but I totally understand this compared to the circuit. I just don't understand how to wire a circuit board and have everything done correctly as far as where they connect to the grounds..etc. No one that I know of can build any circuits either or lend a hand for that matter.

So I end up using another pot per driver it seems...no biggie. Another 5 bucks total for the build. I'll just hide the other pot under the hood and leave the 0-10v one accesable thru the hood.

 

[niffer]

this might be a dumb question, but will you have to control this manually, or can it be automated?

 

[evilc66]

Hook the driver directly to a Reefkeeper with an ALC, Apex, or Profilux, and you don't need any of this stuff, and it will automate everything.

 

[Gomer]

Keep in mind that the Meanwell ELN-60-48D doesn't do well when you exceed 10.6v

 

[der_wille_zur_macht]

this might be a dumb question, but will you have to control this manually, or can it be automated?

Hook the driver directly to a Reefkeeper with an ALC, Apex, or Profilux, and you don't need any of this stuff, and it will automate everything.

Or, if you're looking for "cheap" and don't mind a bit of effort (though that's subjective), spend $30 on an Arduino and $5 on some external components to build your own controller.

 

[evilc66]

That's a great option too if you want to learn how to program. I need to get off my butt and finish mine. Too many other things going on.

 

[der_wille_zur_macht]

If crudely dimming LEDs is the only thing you want to do, it's very easy with an Arduino, especially if you go for a PWM-dimmable driver (buckpucks, P-type ELNs). Two wires, and three of four lines of code modified in the "fade" example sketch included with the Arduino software. More fashionable dimming is easy too, because several people have already written and shared code.

To date, I've used an external RTC with my arduino LED dimmers, but you could use the clock to count time, especially with the new time library.

The only real problem with using an Arduino like this is that it's easy to get carried away. You start out thinking "oh I'll just use it to dim LEDs" and before you know it, you're trying to download weather data from the great barrier reef in realtime so you can match your VFD-controlled closed loop to current wave strengths in nature. :lol:

 

[Skeptic_07]

DWZM.. how much more difficult is it do use an adruino to dim the D type meanwells?

I only ask because my plans was to get my fixture up and dimming with reefkeeper and ALC and then start tinkering with DIY controllers so I needed to go with the D type, not knowing it would be more difficult down the road.

 

[der_wille_zur_macht]

Not much more difficult. You basically need to convert the Arduino's 5v ~500Hz PWM signal to a 0-10v analog signal. This can be a pretty simple circuit, do some googling.

Or, you can make use of the I2C, One Wire, Serial, or SPI busses on the Arduino and use an external IC to generate the signal in response to commands from the Arduino. This is the route I would go, especially on a larger build, since it gives you more flexibility and doesn't tie up the precious PWM pins on the Arduino itself..

 

[vnguyen]

If crudely dimming LEDs is the only thing you want to do, it's very easy with an Arduino, especially if you go for a PWM-dimmable driver (buckpucks, P-type ELNs). Two wires, and three of four lines of code modified in the "fade" example sketch included with the Arduino software. More fashionable dimming is easy too, because several people have already written and shared code.

To date, I've used an external RTC with my arduino LED dimmers, but you could use the clock to count time, especially with the new time library.

The only real problem with using an Arduino like this is that it's easy to get carried away. You start out thinking "oh I'll just use it to dim LEDs" and before you know it, you're trying to download weather data from the great barrier reef in realtime so you can match your VFD-controlled closed loop to current wave strengths in nature. :lol:

Could you post or show me the link to the complete part(s) and software need to do the dimming option for LED using PWM meanwell?
Thanks!

 

[der_wille_zur_macht]

Hardware:

1) An Arduino or compatible microcontroller. There's a list of official hardware here:

http://arduino.cc/en/Main/Hardware

There are also a TON of "unofficial" compatibles. Price ranges from $12 - $60. For these purposes, any of them will work just fine. It's probably best practice to get a Duemilanove (the current reference design) or 100% compatible, since that will give you the most compatibility with other hardware if you want to do other things.

2) Some wire, solder, a project box, etc.

3) Optional - a real time clock. This will improve timekeeping accuracy, and add a failsafe since most RTCs are backed up via battery, so the controller will know what time it is if a power outage occurs. Sparkfun sells one based on the DS1307 but it's rather overpriced.

Software:

1) The Arduino environment. This is downloadable here:

http://arduino.cc/en/Main/Software

That will allow you to write and upload programs (sketches) to the Arduino's processor. You don't strictly need this software, but it makes things vastly easier if you're just getting started.

2) A sketch - Arduino calls programs "sketches." You need to write or find a sketch to dim the lights for you. I mentioned the "fade" example above. This is a simple program that just ramps an output pin up and down. From there, it can get as complicated as your heart desires. Several folks have posted examples of what they've done in different threads, maybe they can repost here. Typically, a sketch will iterate through a loop indefinitely. At the beginning of the loop, it will check what time it is, and perhaps other conditions. Then, it will set the output pins connected to the LED drivers to the appropriate value, and then it just repeats.

 

[vnguyen]

DWZM,
Thanks alot for the info! I'm start looking @ this now as I'm waiting for LED. I've not decide on which driver that I'm going to use yet (either manual or PWM). Is there a thread/link that show step-by-step on how to connect the Duemilanove to the meanwell driver? I saw on the Duemilanove board that has pin label PWM on pin 3,5,6,9,10,11. Do we connect the cable from the meanwell to these pins? Let say I'll have 4 driver to power 48 LEDs. Could you show me how to connect these driver to the board?
Thanks!

 

[der_wille_zur_macht]

Yes, you have the basic ideas - the PWM pins have the ability to provide a PWM signal, so you connect those pin(s) to the driver's dimming circuit, then connect the GND from the dimming circuit to the Arduino's GND.

I don't really want to attempt any more specific discussion than that with meanwell drivers because I've never used them (I build my own drivers. ) - I know others have done this, so maybe they can provide photos or more specific information - but in the end, it's pretty simple.

 

[evilc66]

It would have to be experimented with, but you could probably just pwm the ELN "D"s. It will all be down to the rise and fall response of the analog input, but with a low frequency pwm, it could work. PWM to 0-10v is a little harder.