Control/Dimming Analog control of 0-10v LEDs

Les

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Feb 24, 2004
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DFW, Tx.
It seems that 0-10v dimming is making a comeback (or actually never left) in the architectural market, and it has me thinking about a project.

We are currently redoing our lobby areas and part of the longterm plan is adding lighting in areas where it wasn't originally. We have gotten around this in the past by using tracklights aimed all around, but that looks awful - and since we have moved to LED in the lobby, the dimming is marginal at best.

I happen to also have a pair of Off/Take Control wallplates by EDI which are basically new old-stock. I have been told by a former EDI tech that they are 0-10v. I see a lot of LED drivers out there that can dim using a 0-10v signal, and that LEDs in general can achieve better dimming this way. I was also told by this EDI tech that the op-amp in the wall plates won't pass much current, so I'd probably need to add buffers after the controls in the signal chain.

This is entirely a pet project, but also an experiment on my part while also hoping I can give these like-new wallplate controls a new life. Does anyone around here have any experience with 0-10v control of LEDs? I know we have a bunch of analog gurus around here and I would love to get some insight.

The wallplates appear to receive +15vdc for their own power, but I can confirm that with Alan Child. I just don't want to bug him too much since my LED idea is a bit esoteric and likely not in his wheelhouse.

Of course, all permanent 120v electrical work will be supervised and inspected by a commercial electrician.
 

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tyler.martin

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Feb 10, 2009
Location
Canada
Most modern LED fixtures/drivers that use 0-10v are sourcing the current, and your controller is required to sink the current. There are standards and requirements for drivers to be Class 2, ie: isolating the low voltage control side from the high voltage side. There are also standards for the amount of current that the driver generates, off the top of my head its .5ma. In my travels i've seen drivers output as much as 7ma per driver, and some newer fixtures that contain multiple LED elements might have multiple drivers chained together in the unit. You should have seen my face after troubleshooting tons of 0-10v dimming issues with an electrician, and speaking to the fixture manufacturer who claimed their drivers only output .5ma, but then when I actually opened the can there was 6! drivers in each fixture...

Anywho. We routinely use 10k slide pots to test the dimming line, usually with a diode or two to protect the pot however, I usually find that you never quite get a 0% dim level on a slide or rotary pot.

So the important take aways, are:
- Figure out how much current your fixtures are generating with a DC amp multimeter
- Figure out how much current the controller can handle. If its more than the fixture amount. You're in business.
- Wire it up so its +10v common (usually the purple wire from the fixture) and then your grey wires (returns) are your channel controls.

If you want to buy something new, look at an Echo Room Controller, and some Echo stations.
 

Les

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Feb 24, 2004
Location
DFW, Tx.
Thanks, @tyler.martin for your response. I'll admit that I guess I had my (figurative) wires crossed, because your post raised more questions, but better for me to know this now. Here's what I have been told about my controls from an EDI Tech.

- The output amps are LM358 and the sliders are 10k ohms, so whether the board has the power to drive an LED driver is dependent on the capability of the op-amp vs the current requirements of the LED, and there is only one LM358 per slider board. This is where the discussion of a buffer between the control signal and the LED came in to play. I believe we were running on the assumption that it would work the other way, in that the 0-10v from the board would drive the driver. I saw a 5ma rating on one and assumed that's what it needed as an input current on the control side.

- The buffer Alan (EDI Tech) described is a 6" x 1 1/2" board with a 14-pin terminal strip and 6 op-amps (one per channel) with associated resistors in a line between them.

- (showed Alan an example 0-10v dimmable LED driver) "Doesn't state control voltage current requirements. I would put a buffer on each controller output channel. C1, C2, etc. Then you can be sure. Each one going to fixtures."

- "All common control channels will be joined prior to the buffer, then go to their respective dimmers."

At the moment I'm kind of in the weeds in feeling like our thought process was backwards. These panels were designed to control 0-10v dimmers, so probably wouldn't be designed for any current coming in from the control line. To further confound things, I saw a video last night that also described 1-10v drivers, which seem to work in a slightly different manner. Luckily dimming all the way to zero isn't needed so much, since this is only a small lobby area - but it would be nice to be able to turn the lights off at the end of the night. Switched power is available in that area, so if push came to shove, that switch could kill power to the drivers.

Another "luckily" is that I don't have any fixtures, so the drivers could be somewhat be planned around the needs of everything else in the system.
 

Mac Hosehead

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Sep 10, 2014
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Shark Tank
You can think of the control line on a 0-10v LED or fluorescent fixture as having a pull-up resister to 10 volts. So if the line is floating the fixture should be at full. The wall panel has to pull down the voltage on the control line to dim it to off. The EDI panels are not designed this way and, typically, will have a diode after the slider that will prevent this. If you can add an op-amp buffer to the output of each channel then this should be able to drive the control line of the 0-10v fixtures.
 
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Les

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Feb 24, 2004
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DFW, Tx.
Thanks, Mac. That must have been Alan's line of thinking as well. Sounds like the best thing I can do is get a few drivers, a DC Amp multimeter (or make sure the one in my kit can suffice) and start designing a buffer circuit. I found a few ready-made op-amp boards online, mostly designed for guitar pedals and the like. I still have a lot to learn and understand --- hopefully I can do that without blowing up my control stations.

You're right; this is in no way what EDI had in mind when they designed these stations. I've just had them kicking around for years and think they're a neat looking and well-built piece of gear. Hoping to put them to use in some kind of project because I think they have a few decades of life in them.
 

Malabaristo

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Jul 11, 2008
Location
Wisconsin
I want to amplify an important part of what Tyler said that's easy to skip over: 0-10V architectural dimming uses the control signal to vary between the driver's minimum level and full. For most products that's 10-100%, for a few products that's 1-100%, and for a very select few products thats 0.1-100%. In order to get the light to actually turn off, you will also need a way to control power to the fixtures. There are a few exceptions to this rule, and they're mostly in that 0.1-100% category. Even the ones that do dim to zero light output with just the 0-10V signal will still benefit from being switched off when not in use for extended periods.

Also, on a related topic: remember that the min level listed in spec sheets for this kind of light describes the brightness as measured by a light meter. A min level of 1% may sound pretty good, but it's way brighter than you would expect if you're picturing a theatrical dimmer set to 1%. That's probably less critical in a lobby setting, but it is a common source of confusion and disappointment--especially with a 10% min level.
 

Les

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Joined
Feb 24, 2004
Location
DFW, Tx.
I really appreciate everyone's input on this. This is as much of an academic exercise as it is a practical one. That being said, maybe I should just stick a Doug Fleenor DMX8DIM and a Northlight converter in there. It would cost some money, but we have a handful of old Altec 9444A amps to sell which could possibly fund it.
 
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Malabaristo

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Wisconsin
If you're in it for the learning experience, you could go in a different direction. Use the panels you have as analog inputs to an Arduino (or Raspberry Pi, or any other similar product), convert to DMX, and use that DMX signal to control whatever mix of ETC Foundry power controls correspond to the fixtures you will be using. That would satisfy your desire to at least partially reuse some classic hardware and give some motivation to learn additional electronics/programming skills. Alternately, I would look at the ETC Echo family for both user interface and power controls.
 
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Les

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Feb 24, 2004
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DFW, Tx.
Use the panels you have as analog inputs to an Arduino (or Raspberry Pi, or any other similar product), convert to DMX, and use that DMX signal to control whatever mix of ETC Foundry power controls correspond to the fixtures you will be using. That would satisfy your desire to at least partially reuse some classic hardware and give some motivation to learn additional electronics/programming skills. Alternately, I would look at the ETC Echo family for both user interface and power controls.
I love this idea. Our main sound engineer, who is also a network engineer, loves using Arduino/Raspberry Pi for stuff. He will take this project and help me run with it I'm sure.
 

teqniqal

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Apr 26, 2009
Location
Dallas / Fort Worth, Texas
One consideration to keep in mind when dimming multiple devices that use 0-10v control is that they don't always track well together, particularly at the bottom end of the dimming range, so you can end up with twenty lights with twenty different output levels. 0-10v is an IMPLICIT control, whereas DMX and DALI are EXPLICIT control schemes. IES TM-23-11 is a useful guide for understanding different dimming control protocols.
 

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