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Author Topic: DMX basicis for a dense soul - thread  (Read 19587 times)

Neil Speers

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DMX basicis for a dense soul - thread
« on: January 10, 2017, 06:46:31 PM »

I'm hoping I can get a bit of help learning the basics of DMX.

I'm a fairly tech savvy kinda guy - I've run PA systems for bands for decades, I figured out how to run pro-tools back in the day without instructions (probably missed a bunch but I could record) and I use Logic Pro now. I've even built a few small electronics pieces. I'm a photographer 'by day' and also teach Photoshop, Illustrator, inDesign, XPress etc. Like I said - fairly tech savvy.

DMX has got me buffaloed. I've been cruising forums, YouTube videos and so on but the basics seem to be right over my head because no-one explains a few things that I've run into.

I would like to run this as a thread - I don't want a huge answer to all the things about DMX, I need to build up my knowledge a bit at a time so I can keep it straight. I hate being in this position, but that's what I seem to need at this stage.

Your patience and help are greatly appreciated.

FIRST QUESTION:

I have four flat eBay LED RGB lights and I bought an ADJ 3C RGB IR - and it turns out they are totally incompatible.  The lights - I have discovered - only work on Channel 7. The Controller only works on Channel 1.

On the back of the lights are four buttons with LCD display - and I get that you can get all kinds of cool effects by going through that if not using a controller.

My understanding is that to get a controller to work with it - you set it to "d001"

What is d002, d003, etc used for? How do you use those with a 'compatible' controller?
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Neil Speers

Neil Speers

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Neil Speers

Len Zenith Jr

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Re: DMX basicis for a dense soul - thread
« Reply #2 on: January 10, 2017, 08:33:15 PM »

A DMX universe has 512 channels. Each channel can be assigned a number from a controller from 1 - 255. Imagine a mixing board with 512 channel faders. If the fader is at the bottom, that channel output is zero, if the fader is at the top, that channel output is 255, when the fader is in between then that output number is in between. That is all DMX is.

Your specific fixtures need 7 consecutive channels to operate its functions, any 7 consecutive channels out of the 512 available will do. It isn't channel 7, it is 7 individual channels or as my example above, you need 7 consecutive faders on your 512 fader mixing board to make this band (fixture) play.

Unfortunately the controller you bought only has 3 channels. Channels 1, 2 and 3. That makes it an odd ball controller as most controllers can operate the entire 512 channel DMX universe. Yours only broadcasts on 3 out of 512 channels which makes it only useful for very specific RGB fixtures probably only made by the same manufacturer as the controller. Unless you only plan on using those very specific lights, get rid of that controller. Other than some basic display case lighting using those proprietary fixtures, it is useless.

Now I said your lights need 7 consecutive channels, which 7 doesn't matter. That is where the d001, d002, etc comes into play, you have to let the fixture know where to start reading. Normally you would tell your controller that fixture 1 starts at dmx channel 1, then you would set your fixture to d001. Now your fixture will read channels 1,2,3,4,5,6,7 and ignore the rest. Now if you want all the lights to do the same thing, then set them all to d001. However if you want individual control over each light then you have to set a new unique address for the rest of the lights. For the next light, if your controller allows you to set fixture 2 to the next available channel then set it to channel 8 (channels 1-7 are being used) and set your light to d008. That will tell your fixture to ignore all other channels except channels (8,9,10,11,12,13,14). Some cheapo controllers will make you go up 16 channels per fixture no matter what so in that case you would set the second fixtures address to d017. Keep on going until you have it done.
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Jeff Lelko

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Re: DMX basicis for a dense soul - thread
« Reply #3 on: January 10, 2017, 08:57:28 PM »

Hi Neil, I'll do my best to help you out!

First of all, congratulations on deciding to invest the time to learn lighting and DMX.  There's definitely a bit of a learning curve to it, but once you understand what's really going on it's not difficult at all.  I'll also try to respect your wishes and not write a dissertation about DMX!

So before I address why your controller and lights aren't fully compatible, it's important to understand what DMX actually is.  To give a highly simplified definition, DMX is a digital protocol that is universal across intelligent lighting and is used to send information from a controller to your light fixtures, telling them what to do.  These "instructions" are broken down to 512 unique channels per universe as it's called, and each channel can be set to a value ranging from 0 to 255.  You string the lights together with DMX cable (often XLR cable is incorrectly used), starting with the controller and ending with the last fixture, or to be proper, a terminator.  This is called a Daisy Chain.   

Now, it's also important to understand that your controller does not know what light(s) are plugged into it, nor do the lights know which controller is sending them instructions.  Every DMX board on the market, from the ADJ DMX Operator to a GrandMA sends the exact same data packets to any light that might be listening.  So what does all this mean and how does it end up controlling a light fixture?  Well, each DMX light fixture will use a set number of those DMX channels I mentioned.  In your case, the fixtures you bought will use 7 channels of DMX.  That means you can control 7 unique parameters on these fixtures via DMX.  Many fixtures have different "modes", where you can utilize 3-channel control, 5-channel control, etc, as an example, depending on the fidelity of the control you want over your fixtures.  In your case, let's just stick with 7 channels for right now.

So it'll take 7 channels of DMX to control your fixture...but there are 512 channels of DMX!  What about the other 505?  Well, your 7 channels of control doesn't have to start with channel 1.  This is where setting the DMX address comes into play.  If you set the address of your fixture to d001 (Channel 1), the corresponding channels 1-7 on your light board will control the light.  If you set the address of your fixture to d101, then channels 101 - 107 on your light board will control the light.  Remember, lights and controllers can't detect each other, so you can repeat the address on other fixtures if you want identical behavior between them, you can overlap address in some cases (though you generally try to avoid that), or you can stagger your addressing to say 001, 008, 015, and 022 if you want individual control of each of your four lights, corresponding to channels 1 - 28 on your light board.  All the other channels of DMX that don't correspond to your fixture's address channel or subsequent 6 channels will pass harmlessly through the fixture and be ignored.  The lights also don't have to be in numerical order by address.  Make sense so far?

So why isn't your board fully compatible with the lights you just bought?  Well, not all light boards are created equally, and this is part of what sets a $50 light board apart from a $5000 light board.  Simply put, not all boards can control all 512 channels of a DMX universe.  As an example, my ETC Congo Kid light board controls 2 universes of DMX - that's two runs of 512 channels, each, totaling 1024 channels of DMX that I can control from that single desk.  In your case, the ADJ board you have can control only 3...so channels 1, 2, and 3 will have data streaming out from your board on them, the other 509 will be silent (0-value).  So...unless your lights have a 1-channel or 3-channel DMX mode on them, you won't be able to control all 7 channels of their DMX parameters from a board that can only utilize three channels and thus things won't work as you'd expect.   

Does that help straighten things out at all?  I don't want to overload you with info and am afraid I already wrote too much, but I'm trying to give you a full enough story so that you don't get even more confused!
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Neil Speers

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Re: DMX basicis for a dense soul - thread
« Reply #4 on: January 10, 2017, 11:45:21 PM »

Len and Jeff - thank you for taking the time to explain this to me.

If the light doesn't have a '3 channel mode' it won't be able to be controlled by the ADJ board I bought. Alternatively it could run 3 single channel dimmer packs set to channels 1, 2 and 3?

What I found was that I could get the red and green lights to kind of work, but the blue wouldn't light up at all.  So that would be because the first channel on the light is the ' R G B H master light-dimmer' (according to the sheet with the light) - and channel 4 which controls Blue isn't there at all.

According to the sheet - channel 5 is empty, channel 6 controls functions like strobe, gradients change, pulse change, etc. Channel 7 controls the speed of the settings in channel 6. So if I had a four channel board, I could at least get the all three channels to light up and give me various colours without the fancy functions like gradients/strobe/etc?

If I have this right, a board with 7 channels will control this light, if it has 14 channels it could control two lights independently with the second light set to start at channel 8, if 21 channels then 3 lights, etc.

I looked at the Chauvet FOOT-C 36 Channel Lighting Foot Controller - which the description classifies as serving six sets of 6 channel fixtures - if I used my 7 channel lights it wouldn't work great because I only see 6 'channel' knobs (labeled R,G,B,Am,Wh,UV) and so the 7th Channel wouldn't be addressed until the second 'set' and so wouldn't work well with my fixtures.

Whereas I looked at a 16-Channel DMX-512 Controller on ebay - which has 8 channel sliders which should actually work for two lights with the 8th channel being surplus to the light and the second light set to start at channel 9? If that's the case could I add on a 1 channel dimmer pack to control a spot light set to channel 8?
« Last Edit: January 11, 2017, 12:21:45 AM by Neil Speers »
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Neil Speers

Scott Holtzman

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Re: DMX basicis for a dense soul - thread
« Reply #5 on: January 11, 2017, 12:11:11 AM »

Len and Jeff - thank you for taking the time to explain this to me.

So Jeff, you said that if the light doesn't have a '3 channel mode' it won't be able to be controlled by the ADJ board I bought. What I found was that I could get the red and green lights to kind of work, but the blue wouldn't light up at all.

So that would be because of the lack of data on the other four channels that the light would 'expect' to be there?

So for my clarification - and I know there probably aren't boards that do this but... if a board has 7 channels it'll control this light, if it has 14 channels it could control two lights independently with the second light was set to d008, if 21 channels then 3 lights, etc.

I looked at the Chauvet FOOT-C 36 Channel Lighting Foot Controller - which the description classifies as serving six sets of 6 channel fixtures - if I used my 7 channel lights it wouldn't work because I only see 6 'channel' knobs (labeled R,G,B,Am,Wh,UV) and so the 7th Channel wouldn't be addressed and so wouldn't work with that light.

Whereas I looked at a 16-Channel DMX-512 Controller on ebay - which has 8 channel sliders which should actually work for two lights with the 8th channel being surplus to the light and the second light set to start at channel 9. If that's the case could I add on a 1 channel dimmer pack to control a spot light set to channel 8?




Yes the foot-c is the wrong choice for you too.  It's clunky too.  I have one and tried real hard to like it but it just isn't as easy to use for a band member that is used to a 4Bar or such.


That eBay listing doesn't show the DMX assignments.  Can you scan the table from the instructions (or take a pic) and post it?


The other item that I think is unclear to you is the value after the d001 for example is the starting DMX address of the first channel of the fixture.  It's an offset value that is added to whatever function is controlled by channel 1.


So if channel 1 is red, 2 is green and 3 is blue and 4 is dimmer 5 is flash and you set the fixture to d006 then that fixture will respond to red on channel 6, green on 7, blue on 8 dimmer on nine and flasher on 10.  Does that make sense?


Two fixtures can have the same offset and the fixtures will then respond together.  You can't have dissimilar fixtures on the same channels because they perform different functions.







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Len Zenith Jr

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Re: DMX basicis for a dense soul - thread
« Reply #6 on: January 11, 2017, 12:18:24 AM »

What I found was that I could get the red and green lights to kind of work, but the blue wouldn't light up at all.


So that would be because of the lack of data on the other four channels that the light would 'expect' to be there?

Each channel would control 1 attribute of the fixture.
For example:

channel 1 - master dimmer
channel 2 - red
channel 3 - green
channel 4 - blue
channel 5 - strobe
channel 6 - preset colors
channel 7 - built in shows (color fade, etc)

If you were missing channels 4 -7, you wouldn't be able to access those attributes. The manual of your lights should tell you what each channel does. If it doesn't then trial and error would be the only way to figure it out.

So for my clarification - and I know there probably aren't boards that do this but... if a board has 7 channels it'll control this light, if it has 14 channels it could control two lights independently with the second light was set to d008, if 21 channels then 3 lights, etc.

Exactly, however some boards (like the obey series) will allocate 16 channels for a fixture and if your fixture only uses 7 channels then the remaining 9 go to waste. There is a bit of a work around for this but it isn't ideal.

So if I looked at the Chauvet FOOT-C 36 Channel Lighting Foot Controller - which the description classifies as serving six sets of 6 channel fixtures - if I used my 7 channel lights I could use the first 35 channels for 5 lights? Or would I need a board designed for 7 channel fixtures?

You need a board designed for 7 (or more) channels because the remaining channels of the light would be on a different fixture page. It would be too confusing to keep track of and program, especially for on the fly changes like dimmer changes.

Assuming I could use the 7 channel lights, can I use mixed lights - ie if had a spot that was 1 channel (ie a white spot) that could be on the 36th channel?

Yes, DMX is mix and match. You could have a 13 channel fixture followed by a 5 channel one, followed by a 17 channel one. As long as you address each one to your board then all is good. You have 512 channels to use as you wish. They don't even have to be all lights, hazers, fans, relay packs can all be in there too.

Maybe tell us what you are trying to do and someone could recommend a board for you that fits your budget.
« Last Edit: January 11, 2017, 12:30:09 AM by Len Zenith Jr »
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Neil Speers

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Re: DMX basicis for a dense soul - thread
« Reply #7 on: January 11, 2017, 12:35:31 AM »


Yes the foot-c is the wrong choice for you too.  It's clunky too.  I have one and tried real hard to like it but it just isn't as easy to use for a band member that is used to a 4Bar or such.


That eBay listing doesn't show the DMX assignments.  Can you scan the table from the instructions (or take a pic) and post it?


The other item that I think is unclear to you is the value after the d001 for example is the starting DMX address of the first channel of the fixture.  It's an offset value that is added to whatever function is controlled by channel 1.


So if channel 1 is red, 2 is green and 3 is blue and 4 is dimmer 5 is flash and you set the fixture to d006 then that fixture will respond to red on channel 6, green on 7, blue on 8 dimmer on nine and flasher on 10.  Does that make sense?


Two fixtures can have the same offset and the fixtures will then respond together.  You can't have dissimilar fixtures on the same channels because they perform different functions.

Sorry  - I was busy revising my previous post as ideas occurred to me.

Here's the sheet that came with the fixtures. Sorry for the awful iPhone scans.
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Neil Speers

Neil Speers

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Re: DMX basicis for a dense soul - thread
« Reply #8 on: January 11, 2017, 12:49:12 AM »

Here's what I have - four 36 watt 7 channel LED fixtures and three 25 watt 7 channel LED fixtures. As well I have two non-dmx 3 watt white spot lights. I also have a 8 or so DMX cables.

I have two light stands with the ability to put a 10' truss between them. I also have a background stand (from photography) that I put up a sheet with our logo on - and I clamped the 25 watt lights to.

Mostly this is for use with my band - however I may use for other events (I occasionally rent out the PA for business / presenter functions or other bands.)

Until now, I've just set each light to cycle slowly through colours on its own.

Ideally I'd have separate control on each light, but I also don't mind ganging some together in order to save channels - my thought was the three 25 watt lights set to be the same behind the band and two of the 36 watt lights on each side from the front of the band each with its own control.

Ideally my budget would be $100 but I could go $200 - but I've already spent a lot in the last year on the PA so money is starting to get tight. I know that's really low and I wish I had enough for a really cool controller, but this is what it is.
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Neil Speers

Len Zenith Jr

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Re: DMX basicis for a dense soul - thread
« Reply #9 on: January 11, 2017, 12:54:26 AM »

Well, it looks like you are in luck; bottom of page 2:

press D(save key) for 5 seconds to enter 3 channel mode, then press D again to save.

That gives you 3 channel RGB mode. You should be able to use your current lighting controller although you won't have individual control of your lights, they will all move together. You probably still have to address all of them to d001.
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ProSoundWeb Community

Re: DMX basicis for a dense soul - thread
ยซ Reply #9 on: January 11, 2017, 12:54:26 AM ยป


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