PWM dimming (LDD) with multiple power sources

[sfsuphysics]

So I found out the "hard way" today that I can't use a single Typhon controller to control LEDs that are driven with LDD drivers off of multiple power sources. Nothing "bad" happened, just the common ground the Typhon PWM wires attach to isn't a ground for the power source that is making one set of LEDs fire up.

Now just to test if my wiring is kosher, I put the Typhon common to the new driver, and yeah the LEDs dimmed just fine. I was thinking this might be an issue but was hoping it was not.

So the 64 dollar question is what solutions do I have?
Is there a workaround so I can use a single Typhon to control multiple drivers from different power sources?
Am I stuck with needing to buy another Typhon controller?
Perhaps I should just get something like a Storm X with 16 channels, and then I'll "future proof" additional LEDs I toss over the tank.

 

[mcgyvr]

But you can.. You should tie ALL the grounds for all power sources together and the typhoon ground so they are all at the same potential.

 

[sfsuphysics]

Well tied the grounds of the power supplies together, still didn't do it. The typhon is not connected to a ground, it's connected to V- which is the DC side of things. So perhaps I think it's sending a weird signal because the V- it's plugged into is a different V- for the LEDs.

 

[mcgyvr]

Well tied the grounds of the power supplies together, still didn't do it. The typhon is not connected to a ground, it's connected to V- which is the DC side of things. So perhaps I think it's sending a weird signal because the V- it's plugged into is a different V- for the LEDs.

I didn't mean "earth/chassis ground".. It just meant the negative side of all the DC supplies.. thats ground (or return) to me and earth/chassis ground is the "other" ground.. most of the time you can also connect one of the negatives of the DC supplies to chassis ground too without any issues but its usually not necessary and many power supplies capacitively couple to the chassis anyways.

if all negatives are tied together you shouldn't have any problems..
They are just "floating" now so you might be having problems with that.

 

[sfsuphysics]

Hmmm, didn't even think about tying the V- together. Just know there is a potential difference of 48V between V+ and V- of course doesn't mean that V- is 0V.

I'll give it a go.

Edit: I just thought they're different power supplies too, one is the Meanwell SP320 the other is the SE350, the SP is PFC version. Putting a voltmeter across the V- of each there's a tad under 1V of difference, ditto with the V+. Just wondering if one is going to actually push a little more voltage as a result or will the V+ compensate for the difference V- value?

 

[Gorgok]

You won't have the V+ lines together, so a difference between them is meaningless... Tie the V- lines and adjust the V+ to whatever you need out of each individually, if you care to. Not sure how LDDs deal with excess voltage on how important it is to have it close to the Vf, but i assume yours is okay in that regard.

You could have a lots of different PSUs all with V- tied together, then the V+ goes to each different device that needs those voltage levels. I actually have 3 of those in my setup now; 5V, 12V, and 24V (adjusted to 22V).

 

[sfsuphysics]

Awesome, thanks. That seems to have done the trick.

 

[mcgyvr]

no prob