Arduino & Mean Well LDD Drivers

donnie · Sep 16, 2013

Need a little help here... not sure why I can't wrap my head around this.

I'm swapping out my Mean Well ELN-60-48P drivers for some LDD 1000HW drivers. I thought it would be pretty easy to hook these up but I started poking around for some wiring diagrams just to double check myself and I've found 4-5 of them and they're all different, so now I'm totally confused.

The VCC+/- and the LED+/- are simple enough and I understand that the power supply and the Arduino will need to share a common ground. What's confusing me is the PWM pin. I assumed (I know, I know...) that I could just hook the PWM pin straight from the Arduino to the LDD pin, but I'm reading where people are frying their boards (or just the pins) and if the Arduino gets disconnected, the LDD will output max voltage to the LEDs so you should put a pull-down resistor between the PWM pin and ground, then others are saying to protect the Arduino, you could put an NPN transistor in between, and then others are saying you should add diodes...

Can someone explain to me what is the most preferred way to hook these up, and why?

Would this work?

Edit: Here's the original (larger) diagram: https://donnie.co/aquarium/arduino-ldd.png

Reefing Madness · Sep 17, 2013

:bump2:

bct15 · Sep 17, 2013

Im building a DIY led controlled via arduino myself and am going to order these drivers to replace my mean well 48-p drivers to have a much cleaner install. At first glance your diagram looks right to me, I don't think you need a transistor. People who are using them typically are misunderstanding what pwm is and use them to get a 10v signal on the pwm, but it isn't about the voltage level on pwm but the frequency and the stock 5 volt level is just as good as a 10v signal connected with a transistor.

A diode never hurts that is for sure, a diode is like a flow valve (only let's current flow in one direction) and if you don't want current flowing back into something adding a diode on that circuit is the way to go...diodes are typically reccomended to protect circuit boards and brains. LEDs are actually diodes so if you don't have one you could just stick a cheap led on there.

I can't remember exactly but I think you want your led chain and your power supply on the same ground, not necessarily your arduino which is going to be running on something like 6-9 volts. Your ground for the led chain needs to support the full 48 volts. Having your arduino itself on a separate ground would serve to protect it because 48 volts are not on it's circuit.

On a side note, what are you using to do your sketch ups?

donnie · Sep 17, 2013

Thank you! I've been afraid to put this to the test in fear that I may fry something. I completely understand why/how they're using diodes now. My basic electronic skills are a little rusty and I know I've read a million times what diodes to but it just wasn't clicking until you explained it just now.

So, if I remove the wire between the Arduino ground and the PS, I should be okay? I'm guessing there's already a path from the led- to the PS vcc- through the driver?

I'm using Fritzing for the sketch-ups. Windows/Linux/Mac and open-source

http://fritzing.org

ignatz · Sep 17, 2013

I'll throw another option out there for you to consider: opto-isolator. The biggest benefit is that it will protect your Arduino and does voltage conversion if your Arduino and driver are different. The device is simple to use and fairly cheap. As a starting point, look up the PS2501-x (x is the number of PWM pins you want to protect) series.

donnie · Sep 17, 2013

Well, that didn't work. They just come on full power, no dimming... The only difference from the diagram above is that I didn't connect the ground of the PS to the Arduino ground. I tried them straight from the PWM pin of the Arduino (without the resistor) and it still didn't work.

I was under the impression that these were basically plug and play and didn't require a lot of extra circuitry, the main thing I was trying to get away from with the ELNs which I could never get working either... I'm about to light these LEDs up and toss them in the tank.