Control/Dimming Learning DMX512

[flyboydc]

Hello everyone! With a good background in the basic principles of stage lighting and electrics, I has recently been places in command of my highshool's brand new television studio when it comes to technical works. Upon recieving some of our new equipment I have noticed that about 14 of our new LED PAR's are ran exclusively useing DMX and are powered by Edison style power adapters. This has led me to learn as much about DMX512 as possible. So all I'm asking is if someone can give me a basic introduction to DMX512 and what it really is all about. The only prior experience I have with it is rigging color scrollors. I have also purchased the "Recommended practices for DMX512". All help is greatly appreciated. I hope I am making a step in the right direction.

 

[JD]

In a nutshell- DMX512 is a one way (controller to fixtures) serial data line that broadcasts 512 "addresses." Each address represents an 8 bit number between 0 and 255. Some devices, like a dimmer channel, use only one address, and 0 is blackout while 255 is full on. Other devices may use several addresses, like your LED fixture. In those cases, you program a start address (on the fixture) and it listens for data on that address and a set of addresses above that. (Depending on how many channels the device needs.) DMX in it's simplest form is a daisy-chain layout. The last device on the chain should be a terminator.

 

[flyboydc]

Okay JD that actually sounds relativity simple on a small scale. now, Do you start your daisy chain directly from the board or do you always need a DMX splitter? And just to clarify, when you talk about DMX fixtures needing multiple channels, this means that the more channels that you have programmed into the light the more potential you can get from the light. For example, a S4 profile uses only 1 physical dimmer, therefore you can only do one thing, add or subtract electricity. My LED's can use up to 7 channels therefore i can add or subtract electricty, change colors, and mix colors.

 

[MNicolai]

An important thing to know about DMX is that never, no matter how desperate the situation, should you go to someone and say, "What is a DMX and where do we have one?"

A good place to start is with the DMX king-pin himself, Doug Fleenor, aka Dr. DMX. He has some good YouTube videos here and here about good cabling practices.

 

[flyboydc]

An important thing to know about DMX is that never, no matter how desperate the situation, should you go to someone and say, "What is a DMX and where do we have one?"

A good place to start is with the DMX king-pin himself, Doug Fleenor, aka Dr. DMX. He has some good YouTube videos here and here about good cabling practices.

Well that really helped me learn to only use DMX approved wire. Thankyou. What else do you recomend i learn for a basic daisy chain set up. Is programming DMX channels different to patching.

 

[JD]

The splitter allows you to use more fixtures. In general, you should only run a max of 32 fixtures off of the line. If you have a four output splitter, each output leg can have 32 fixtures on it. Most splitters are also opto-isolators so they can help you avoid ground loop issues between the board and between each output leg.

If your fixtures are each 7 channels and you wanted complete independent control, you would set the first fixture to have a start address of 1, the second at 8, the third 15, etc. In most cases, you probably want to have groups of fixtures that are running with the same commands. In that case, each fixture in group 1 would have a start address of 1, group 2 would start at 8, etc.

 

[Grog12]

An important thing to know about DMX is that never, no matter how desperate the situation, should you go to someone and say, "What is a DMX and where do we have one?"

Mike, this sounds like a story I'd like to hear...but don't hijack this thread with it >:>

 

[flyboydc]

The splitter allows you to use more fixtures. In general, you should only run a max of 32 fixtures off of the line. If you have a four output splitter, each output leg can have 32 fixtures on it. Most splitters are also opto-isolators so they can help you avoid ground loop issues between the board and between each output leg.

If your fixtures are each 7 channels and you wanted complete independent control, you would set the first fixture to have a start address of 1, the second at 8, the third 15, etc. In most cases, you probably want to have groups of fixtures that are running with the same commands. In that case, each fixture in group 1 would have a start address of 1, group 2 would start at 8, etc.

Okay so when i do my setup for this TV studio im going to want something like this?

(Daisy Chain)

Console---------DMX Splitter (Optional)---------LED1--------LED2--------LED3-----Etc.

With the addresses. LED1: 1, LED2: 8, LED3:15

 

[MarshallPope]

Yes, that sounds right. One thing to remember, the order of channel assignments do not necessarily have to correspond to the fixtures' physical order in the chain. It is fine, and sometimes easier, to assign the channels so that you have light 1---light two---light 3---etc. However, if it is more logical to have fixture 1 and fixture 8 next to each other on the console because of their physical placement, it is fine to assign channels in a different order, such as light 1---light 8---light 2---light 9---light 6---etc.

That was probably extremely confusing, but my point is this: the channels you assign to each fixture have nothing to do with the physical order of the fixtures.

 

[mstaylor]

Since you are using such a small amount of addresses you might want to skip some numbers to make them easier to use. Make your first light 1, the second 11, the third 21 and down the line. It can make using your lights easier when you are learning, especially if you have to change a light in the chain.