The pull down resistors are used to prevent the LDD's from going "full throttle" in cases where they're being controlled, or dimmed down to prevent Coral bleaching. If the controller fails for any reason and stops sending a PWM signal to the LDD's. The LDD's will turn "Off".
Meanwell LDD driver: for those who want to dim to 0 using Arduino
- Thread starter pwreef
- Start date
The pull down resistors are used to prevent the LDD's from going "full throttle" in cases where they're being controlled, or dimmed down to prevent Coral bleaching. If the controller fails for any reason and stops sending a PWM signal to the LDD's. The LDD's will turn "Off".
rrasco
Active member
Essentially. Like O2 said, it's to prevent the LEDs from turning on 100%, which is what happens when the PWM pin is not used, which happens if your controller turns off. More than likely the LEDs wouldn't get baked, but your corals might.
That was exactly what I suspected.
I'm only driving mine at 700 mA so the original PCB should be fine for my uses with low potential for harm.
At least that's what I'm telling myself since I ordered them before I read that last update.
Count me in for at least 2. I'll take more if you wind up with too many.
Here's a digikey link.http://www.digikey.com/product-detail/en/1727010/277-1947-ND/348696
Use the part # or description to search FleaBay for a cheaper alternative. just search "screw header, 2 position, 3.5mm pin spacing".
letoan
New member
Thank you. Last question. Will all 1206 10k resistor works? Or have to be a specific one?
rrasco
Active member
10k is the value, all 10k resistors are the same (for the most part), except for packaging. In this case, 1206 is the package, so yes, all 1206 10k resistors are the same. AFAIK anyways.
gandalfdgrey
New member
Thanks.
letoan
New member
Thank you.
rrasco
Active member
That's brilliant. I knew there was a reason you did it. :rollface:
I need to start a build thread but in the mean time figured I would post a picture of my completed driver box. I am setting up two x 9' Makers LED rails for my 600g tank. Using 7 different colors split across 22 LDD-H's powered by two Meanwell HLG-240H-54A power supplies. I am also using two ebay voltage adjustable voltage regulators, one for each Makers LED to power the fans and two of Steve's Aquarium Interface drivers to go from two Neptune Apex VDMs. While it's more expensive then setting up a Arduino I wanted to keep everything on my Apex. I ended up going with Molex connectors for everything. A little time consuming but not to bad to do. Thanks
Chicken, can you give more detail about what parts went in to that box? I assume you have a 48 to 5 v converter for powering the Steves interface. How did you hook up the various grounds?
I am doing the same thing and am trying to figure out where to ground it all to get all of the reference voltages right.
Seems like I will have:
LDD 48V input ground
DC/DC coverter 48v input ground
DC/DC converter 5v output ground
Power supply 48v output ground
Steves interface 5v input ground
Did you tie them all together?
Also, what molex connectors did you go with?
Curtie44
Member
First off let me say this thread has been a great read. I've been in the planning phase of my build for a few weeks now and my component list has gone through several different iterations. First it was Inventronics drivers, then it was MakersDrivers then I kicked around the idea of using the Steve's drivers. After reading through this thread and running the numbers, it changed yet again. The LDD-1000H and LDD-700H are now on order (won't ship 'till 4/5 
). I've had an Arduino sitting on a shelf for 6 months or so waiting for this build so I have that covered already. This will be my second build and going over my main display tank. The first one used Inventronics drivers and went over my frag tank.
Thanks to all the contributors of this thread for posting up so much information and also to those taking the time to design boards for these builds. I'm definitely going to be using the LDD 4 driver boards with the pull down resistor in my build. If anybody has placed an order and will have extras, I'd be in for 3 of them. Shoot me a PM.
). I've had an Arduino sitting on a shelf for 6 months or so waiting for this build so I have that covered already. This will be my second build and going over my main display tank. The first one used Inventronics drivers and went over my frag tank. Thanks to all the contributors of this thread for posting up so much information and also to those taking the time to design boards for these builds. I'm definitely going to be using the LDD 4 driver boards with the pull down resistor in my build. If anybody has placed an order and will have extras, I'd be in for 3 of them. Shoot me a PM.
you can add them later with a little jurry rigging.....
not too difficult if you decide you need them.
He soldered all his wires in directly to the bottom of the board where the screw terminals would go and connected them to molex plugs on the box. rather professional looking!
See the open slot? You can kinda see the traces which connect the LDD pins to the terminal blocks which are on the other side of the board. Those have wires connecting them to power in, pwm in, and power out to LEDs.
First off let me say this thread has been a great read. I've been in the planning phase of my build for a few weeks now and my component list has gone through several different iterations. First it was Inventronics drivers, then it was MakersDrivers then I kicked around the idea of using the Steve's drivers. After reading through this thread and running the numbers, it changed yet again. The LDD-1000H and LDD-700H are now on order (won't ship 'till 4/5
Thanks to all the contributors of this thread for posting up so much information and also to those taking the time to design boards for these builds. I'm definitely going to be using the LDD 4 driver boards with the pull down resistor in my build. If anybody has placed an order and will have extras, I'd be in for 3 of them. Shoot me a PM.
sorry so, not on topic but, nice avatar! a refreshing change from the reef related norm
and I just so happen to be listening to them right now....:beer:
