0-10V Dimming Problems

[jimdavis]

We're just finishing up a huge job- a public venue with a high-end theatrical lighting system. I have a few circuits that exhibit flickering while dimming up or down. The fixtures are LED and controlled via 0-10V from dimmer racks. I have other circuits in the building which are using the same fixtures and dimming configuration and they work just fine. The power and 0-10V conductors are run in separate raceways. The building has well over a thousand lighting circuits and I've worked through a lot of issues but this one is getting the better of me. Any thoughts or ideas?

 

[JFletcher]

Wow, big building.

wag, but with that many devices and circuits, I have to wonder if you've gotten a few bad ones (devices or bulbs) from the mfgs. Wouldnt be out of the realm of possibility.

 

[chris kennedy]

Try putting the circuits in question on a different phase.

 

[Electric-Light]

is the troubled one and well working one using the same controller?

Lighting dimming is done with a potentiometer to pull the voltage down. So the first step in trouble shooting is to disconnect the dimming system from 0-10v and sweep from maximum to minimum with the most basic 0-10v dimmer attached across 0-10v wiring. You only need to connect the dimming control wires.

Theatrical dimming is often done with a variable voltage power supply feeding 0-10v into light fixture. Use a ghetto cheap analog DC volt meter(it provides low enough impedance to act as a load) and place it across 0-10v terminals on the dimming system with nothing connected. If you see it providing 0-10v with no light fixture, then you have a sourcing theatrical dimming system. Some dimmers are capable of feeding into theatrical load as well as sinking lighting loads, otherwise, they'll fight each other.

A mismatch requires an interface box. In this case, call Lutron. They'll explain what you'll need.