Hello again,

Is there any risk in running 3 meanwell driver 1-10v dimming circuits in parallel?

My understanding is that there is a risk in running the actual LED's in parallel if preventative measures are not taken i.e. current mirror, however it has been raised in reply on the above posted profilux topic that this could also be a risk.

Re the limitation of the L-ports on the profilux the reply I got was:


and then I had another helpful person provide this information:

So I appear to be ok on the Profilux front.

I may be overcomlicating this, but I am going to try an Noninverting Ampliflier Op Amp solution for doubling my Arduino PWM from 5 to 10V to use the ELN-60 P. My only concern is if this will be jittery. With a low pass filter combined, should work on a "D" as well. A low pass filter will eliminate any jitters.

Anyway I am going to give it a try.

I think this can be accomplished with a LM741 op amp or what I am going to use is the TL082CP Op Amp.

So I am going to try these parts:
1 - TL082CP (these can be either single or double to run two off the same chip)

3X10K .1% tolerance resistors (these are pretty precise so the .1% tolerance is a good price/performance - any lower and you are looking at $7-8 resistors which is pricey) so with .1% tolerance, worse case, you could hit 10V on the high end and 9.5 on the low end as you will never go higher than the Op Amp Voltage source.

Here is the Op Amp calculator link that also shows the schematic. Use 5V on the Rs input and 10K all around on the resistors. ( you could do 22/22/10K to get the same result, but your voltage for the Op Amp would have to 12V and not 10V )

There really should be a couple lines on the Op Amp showing the pos & neg power source for the Op Amp, but seldom are put in the drawing.

Op Amp Circuit link

Like to get feedback on this. Any thoughts?? Am I way off base...

That's one approach. You could also use a boost inverter too for a little more powerful and cleaner output.

So are there any updates on getting this to work with the ALC module?

Not yet. Don't have an ALC module to test against yet.

I was finishing up a 10 led pico light when i had some issues with my meanwell 60Ds. I have two Meanwells each running 5 Cree 3w leds one for white and the other for blue. I tested my led strings as I soldered them up and everything was working great until I mounted everything on the heat sink. Once they were on the heat sink and fired them up they flashed real quick and they were all toast. So I narrowed it down to two possible variables which could have caused the failure. 1) My soldering job could have had shorts in it which became an issue when i mounted it to the heat sink. OR 2) When I was plugging it all in, I plugged in the meanwells in before plugging in the transformer for the dimming circuit.

So i guess my question is whether or not energizing the meanwell with no dimming voltage could burn up a string of leds?

Thanks in advance for the help!

1. Most likely

2. Not likely.

Thanks Evilc66, yeah after thinking about it seemed highly unlikely for the dimming circuit being at 0v at startup causing any issue.

This is off topic for the thread thread, but what is usually the problem with or solution for LEDs that are shorted when metered but show no visible connection to the back plate of the star?

Poor wiring, or shorts to the mounting screws

Have you tested each led? I just used 2AA batteries and soldered wires on the ends and tested each led after it was wired. Pos wire to the + pad on the led and the Neg to the heatsink. If it lights up you have a short. If it didnt turn on when you touched the heatsink place the Neg wire one the - pad and see if it lights up. If it doesnt, they are toast.

I really don't want to hijack this great thread on Meanwells with my inability to successfully solder some LEDs together. Yeah moovinfast I did check them and it appears I fried the whole array. I have built a good number of electronics projects more sophisticated than this so its frustrating to have botched this one up. I guess I underestimated the issues of building LED fixture.

Okay so my first try on the op amp method did not work well. It works fine when there is a constant 5V pwm feed from the arduino. I get a steady 10V output (double). But when I fed a pwm signal from the arduino that was fading in and out, results were sporadic and all over the place. I think my issue is that the op amps I tried (lm741, tl082 and the lm324) are not Rail-to-Rail and significantly less accurate. So when the voltage goes up or down, only a RTR op amp can linearly handle the fluctuations correctly. Non RTR can only hit within 1.5 volts at best. I am going to try the LMV358, which is a quad op amp which is RTR version of the LM324.

I am also going to make a simple transistor boost to see how that compares to the op amp. I will use a PNP transistor but with a voltage regulator (LM8910) which will give a fixed 10V source. I will see which works the best.

Spark Fun Op Amp

I also found these at Spark Fun: It is a RTR LMV358 op amp circuit that has possibilities for the "D" version with (or without) an Arduino. From the schematics, it looks like it runs through two op amps with all 10K resistors and should double the voltage (is adjustable on the circuit with a trim pot), runs through a low pass filter to smooth out the signal to a true analog signal and then the second amp will boost the voltage. Has good potential for people with the “D” meanwell, but since the capacitors filter into a much higher frequency analog signal, not so great for the” P” version. The only thing I am not 100% sure of is the frequency of the analog output (which is set at 15.9kHz ). It should work, but I could not find anything in the ELN .pdf besides the pwm 0-10v has to be below 3kHz. Nothing for the “D” 0-10V. But at a higher frequency, the signal should be very clean for analog. (could also poss. also switch the caps to lower the frequency if needed.) SparkFun might even switch those out to meet specs…

As long as the output stage of the opamp is filtered correctly, the "D" will never see the frequency. Neat little unit.

EXTREMELY IMPORTANT INFORMATION:

The Meanwell ELN-60-48 has a limitation that I had not noticed before, that seems to be causing some people some headaches. It will require a minimum of 6 LEDs connected to regulate properly. I know I have said that one LED should be fine for testing, but it seems that this is a recipe for disaster. I know this message is a little late for some, but for those looking to use these, please pay attention to this.

Sorry for any inconvenience that this has caused people.

Thanks for the info! I wish I had read this an hour after you posted it because I spent another Saturday cooking LEDs. This time I used Teflon insulated wire to minimized the issues of melting the insulation and causing shorts to the star. Then I spent 30 min poking and prodding the whole built with my DMM to check for any shorts, and also tested each LED separately for function. After all that fun I hooked my two meanwells up to the 5 LED strings. One of my meanwells did just fine the other was blinking the blue string intermittently every ~ 6 sec for ~1/2 sec. First I thought there was an issue with my blue string wiring so I flipped the power supplies and it flashed the same was with the whites. So I started poking around and checking everything and no red flags came up. I then went to check the current out of the supply on more time and hooked it to the LED string instead of a dummy load and at that time the meanwell decided to cook the string for good. I putting these on the shelf for a bigger build in the future and I am going to order some buckpucks. Nanotuners made good money off me every week of this project as I beat my head into the wall with these meanwells. FML

Sorry about the issues you are having with your build. Considering that I have not had issues with lighting up one and two LEDs on a driver, it was something that I overlooked. Sorry it had to come to you damaging some LEDs for me to actually look at it.

As a side note, I sent an email to Meanwell about the dimmer's tolerance for excess voltage. He called me back today.

He stated pretty clearly that 10.6v is the maximum tolerance. Anything over that can be damaging.

10.6 is the max.

Hey Evil, no sweat. I appreciate you hunting that info down and now I don't have to troubleshoot an issue that I probably would have just given up on. The weird thing is that one of the power supplies seemed fine with 5 LEDs the other did not and cooked the string. Weird...

Hrm... if 10.6v is the max over voltage and the most you can turn them down via the SVR1 pot is ~41v then you would need a voltage drop of about 30v which would be more than 6 LEDs. With the Cree 3w having a forward voltage of 3.3v you would need 9 to be safe. Does that sound right?

You're talking about two different things. The 10.6V is referring to the dimmer circuit (0-10V), not the driving voltage for the LED's.

Oops my bad...

If I had to guess, the difference wasn't in the drivers, it was in the LED's. All you'd need is a single LED in one of the 5 that couldn't handle what the driver was putting out, and when it fried, you were down to 4-- . I don't know then if the voltage stacks up on them when you have too few like things happen when wired in parallel and one dies, though.

It does if the LED fails as a short. The minimum voltage will be divided up by the remaining LEDs.

In my experience LEDs really like to fail short. Are there any factors that contribute to whether or not they fail open or closed?

Not as far as I can tell. You are right though, they fail short more often than not.

Do you know many amps can the the 'D' and 'P' models take for the dimming?


Also, for the 'P' model, the signal has to be 3kHz or less or it will not recognize it.

That I don't know for sure. I think I read in the thread somewhere that the D model drew 3mA, which isn't much. I'm pretty sure any of the power supplies we have available to us will work fine, but don't take that as gospel.

Thanks. I will call Meanwell and ask. There are bunches of controllers boards that can take a PWM 0-5V input and out put a predefined 0-10V PWM output at a dip set frequency like 300 Hz or 3kHz which would work with the P models. However, they produce 5-15 amps. These are $15 boards that could be a plug and play option.

I am continuing with my op amp design to see how it works. Waiting on my rail to rail & high speed op amps to arrive.... In retrospect, I wish I would have ordered the D models as it is pretty simple to take a pwm input and output a linear 0-10V analog signal. I have had issues with getting good linear results taking the pwm input and getting a good linear output that is still pwm without having to regenerate the pwm signal. (I unfortuntately do not have an oscilator)

Depending on the test with the rail to rail op amps go, I may end up having to run through a comparator to regenerate the pwm (for those of us using the "P" models.)

I was reading the data sheet on the ELN60-48 and wondering about the SRV1. Could this be turned up so to allow an additional LED, making this driver capable of 14 XRE's?

Supposedly if you max the SRV1 out, the max output voltage would be 52.8. 14 XRE's should require around 51.8.

Is this plausible?

In constant current mode, the voltage changes based on the LED requirements. SVR1 won't do a thing for you. 14 LEDs is possible based on the datasheet, but 13 is what I would consider the safe limit.

I just got to test my op amp circuit and the result are perfect. I am a happy man.

I tested two op amps to see how I could linearly increase and decrease the 0-5V arduino pwm signal doubling the voltage 0-10V. So I wrote a real simple program that goes from 0-5V then steps back down in a loop for testing with the Arduino.

Results
TLC084: A near rail to rail high speed (10MHz) op amp steps up and down between .2V up to 8.9V
TLV274: True rail to rail op amp (3MHz) steps from 0-10.05V perfectly up and down doubling the voltage.

Been running the program with the multimeter hooked up for about 1 hour with consistant results. So FINALLY success.

So here is the plan:

I ordered some of these boards that are generic pre-fab pcb boards for $10 each.

http://www.muzique.com/tech/op-amp.htm
The nicething about these boards is there is plenty of space for a lot of resistors and capacitors, but if you don't need them, you just do not put anything on the board and it work great. So no jacking around with prototype board an trying to make runs with solder. Just pop in the resistors and capacitors where needed and a quick solder job and done. The entire circuit will cost about $16.

I just need to order the dual version of the TLV274. The first stage will be a low pass filter that will only allow frequencies up to 3KHz (the max the 0-10V meanwell pwm can see) then run it into the second op amp on the IC op amp and give it the voltage doubling. ( I am pretty sure I can do both in one pass with one op amp, but this is a little easier and since I know each works individually, I do not want to do another 2 week stint figuring out the single op amp circuit that does both.)

I will post the schematics for the circuit for everyone, but I have to go because it is my youngest daughters birthday party today.

Basically these are the parts:

Low pass filter:
2- 10k ohm resistors 1%
1- 4.7 nF capacitor 2%
1 - 6.8 nF capacitor 2%

With the tolerances, the cut off frequency will be between 2732.7 Hz and 2901.7 Hz for maximums which falls within the spec range for the meanwell pwm (0-3KHz).

Voltage Doubler:
2 - 10k ohm resistors 1%
1 - 4.02K resistor 1%
1 - .1 uf capacitor 3%

1 - TLV272 RTR dual op amp

more to come...

Is there an easy way to change this to run with 10V?

Sure. Take the LM317 and the two supporting resistors out and connect 10v to pin 8 on the 555.

Where have you been lately? Haven't seen you hovering around here for a long time.

so just remove the LM317, the 1.5k Ohm and right 10K ohm.
thanks

I'll see how that works for me (or wait till you get a chance for the 0-10V-->PWM circuit figured out. Have "P" drivers as that was what was available at the time and have 0-10V on the APEX)

'I've been a little busy and haven't been posting here much (been reading though). I'll have an array going soon using 18white and 18 RBlue driven by the ELN-60-48-P at 1amp (-25%). I'll post up when I get it rolling

Good deal man. I enjoyed our discussions in the early days of LEDs here on NR. It's changed a bit hasn't it?

yup back then, only 3-4 of us dared touch the subject. Now it is embraced with open arms! Very cool stuff.

I wouldn't put a low pass filter on a square wave like that, all it will do is round off the corners depending on the pwm frequency and slope+frequency of the filter.

I'm sure the Meanwell datasheet means a 0-3khz square wave, and if you run a 3khz square wave through a 3khz low pass filter you don't have a square wave anymore.

That is true. It may work just fine without the low pass filter. I think the pwm from the Arduino is about 400Hz. Leaving out the filter will keep it a square wave, I am just not sure how consistant the freqency would be on the output. I don't have an osciliscope to use for testing.

The only way I know of doing that with an op amp is to use it as a comparator to produce the pwm, which is not difficult to do. I am open to any ideas or suggestions...

It may be a three pass op amp circuit that would work the best. Low pass filter to voltage doubler to the comparator to produce a pwm wave...

The LM555 uses two internal op amp comparators and two internal transistors. It can also be used with the pcb I have.

Has anyone figured out the circuitry change to convert an ELN-60-48P into ELN-60-48D? I am sitting on three P's and really wish I got the D's (ignorance isn't bliss )

Gomer - we have the Ds coming back in late this month (Dec 29). Lmk if you want me to hold a few for you.

I wouldn't mind the D's but I unfortunately am sitting on 3 brand new Ps right now

Let me see if I can sell them off or something lol.

Just verified from the guys on allaboutcircuits forum that the op amp will not change the frequency at all. But the op amp generally will produce more of a triangle wave rather than a square wave, but should still work. The op amp has to be run open loop. Still a digital signal.

However, thanks to Sgt. Wookie on the forum, I have a circuit drawing similiar to what Evil had suggested a while back. He thinks the easiest solution for still using the PIC would be to use a logic level MOSFET or a transistor on your PWM I/O pin. It apparently will would invert the logic, so that 99% ON would be 99% OFF, but that can easily be changed that programming on the Arduino.

1 transistor, two 1/4W 1k resistors, and a 10v Zener diode.

Click to view attachment

I am unfortunately at my in-laws this weekend and cannot build them, but will when I get home and test both to see which works the best. I think both wil probably work fine. This was info I needed to get moving on this. I hope finally put the entire led hood together over Christmas weekend and get it over the tank.

I would think yes, but I wanted to check.
With the ELN drivers, can you have a common ground on the driver side (black wire)?

I have a 4 conductor cable that I want to use for 3 drivers.

Has anyone succesfully built the pwm circuit for dimming? I have now built 2 different versions 4 different times and cannot get the pot to change the brightness??

In doing investigations on how to upgrade the lighting on my BC29, this thread and others have been invaluable. Thanks a ton to all of the guys who contributed thought and analysis to developing various solutions. Plenty of wall imprints on a lot of foreheads I'm sure, but that's the cost of trailblazing! Just wanted to express my appreciation.

I'm still totally up in the air about what direction I'll go, but am leaning towards an Arduino controlling either version of the Meanwell. I'm going to try an Arduino program that will vary the dimming signal over the course of an hour or two, either brightening or dimming in the morning and evening respectively. Hopefully I can put this all in one enclosure with an extension on the USB cable so that I can just plug into the USB/Serial of the Arduino from the outside and have the inside clean for air flow (maybe a small fan driven by the same AC adapter that will power the Arduino... just thoughts right now. Anyone else have the same sort of thing in mind?

Clearly the P and D solutions differ, but people seem to have success either way- which has proven easier or more cost effective seeing as I am parting this out from the ground up? I've read some amount of "whoops I should have got the 'D' version"...



On a somewhat unrelated note, my dad is a machinist so I'm going to try and design a custom heatsink and maximize my surface area within the stock hood, then have him fabricate it. Should be able to add a mirror polish on the bottom (to reflect any possible wasted light) and have everything professionally cut/tapped. I might have to buy him a six pack or something, but that's good savings.

I'll be back as I revise plans! Not sure when I'll pull the trigger on this budget-wise. I am curious about the other solutions that are out there, from open-top to all-inclusive hood specific DIY kits, but the hands-on in me wants to figure this out from scratch, do all the math, and see it come together.

If you have an radio controlled car or plane you can use the radio as a test. The control signal for the servos are PWM. I haven't looked up the spec's of the signal but I think it will work. I also build robots with high school students and we use PWM type signals to control speed contollers on the robot. There are many micro processors that have pwm outputs also. BASIC Stamp from Parallax is one of them that they are extremely cheap, easy to hookup and the program is free.

Parallax Processors

I don't know if this is over your head but this one is $30 plus some assesories need at the bottom of the page.

Basic Stamp 1

You might want to call them....You are used alot in colleges now for teaching and there is alot of free programming examples. I have been working with some of my old robotics students that are now in college with these.

The issues with these for a meanwell "P" is that the frequency on PWM for servos is normally pretty high. The meanwell will only take a PWM 100-3Khz. It will not see the signal if above the 3Khz. Servos require a much higher freqency.

Just a little FYI.

The -25% setting for 1 amp by turning SVR2 all the way counter clockwise does not set to 1 amp. It set to ~250mA.

I thought -25% of 1.3A is equal to 975mA assume you are referring to ELN-60-48 !

BTW, How do you measure and what formula do you used to come out the conclusion of ~250mA instead of 1mA ?

yes, -25% of 1.3 is 0.975 amps. I thought 1amp was a good approximation

No formula. I measured the current out of the ELN-60-48 through 12 XR-Es with a multimeter.