48VDC LDD-H Circuit unable to dim with Arduino?

[Aqualund]

So yeah I'm pretty sure I'm missing something, but I got my 12 led circuit run in series on an aluminum pcb, and it's hooked up to my test ldd-h, and that is hooked up to the power supply...but when I try to dim it on channels that are already set up for dimming (running Jarduino, and tested first the sump channel...and then every other channel after that) I get zero dimming effect.

well actually I get a very very small flicker...almost undetectable. all the other circuits...which are 24vdc are dimming just fine. I rang the wires out, and all have continuity...and they are all hooked up correctly.

I thought it might have been the ldd so I switched them out to a brand new one...nope...same thing. So what gives? why cant I dim the 48vdc circuit? I mean...1200 par might be fun to measure...but my corals wont last long uner that lol.

[mcgyvr]

schematic?
Do you have the grounds tied together?

[Aqualund]

Do the grounds need to be separated to different grounding locations?

[kaskiles]

He's just saying that the Ground running between the LED power supply and LDD input, needs to be connected to the Arduino Ground.

[Aqualund]

yup, that was it...the ground wasn't tightened properly. It's funny how after what was wrong becomes evident...its a new creative way to feel like an idiot lol =P

thanks for the help everyone!