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The Very Simple Guide to DMX

Hello and welcome to The DMX Wiki,

As you may have of seen or heard many times or perhaps even not DMX is sometimes referred to as DMX 512 Or you'll here the word 512 bounded around alot!

This '512' refers to the maximum amount of channels that DMX can have in One 'Universe' so they say, what do I mean by Channels? Well imagine in front of you 512 milk bottles in a row… Each one can contain some milk but only so much and that limit is '255' so the milk bottles in front of you represent the 512 Channels in DMX but what does that '255' refer to? Well that's the maximum 'Value' of the amount of milk your bottle can hold.

and this is how DMX Works imagine your light needs 1 Channel (a milk bottle) and when that milk bottles empty (the values at 0) you get no light output but slowly as you fill the milk bottle with milk (increasing the value) your light gets brighter and brighter until your bottle has got 255 litres of milk (the max), need it dimmer? Then pour some of that milk out! every litre is activating a switch that does something on your light and some lights don't mind having a value within a range for example in the manual it will say 230 - 255 turns the light green so when you fill that bottle up once it reaches 230 and up until 255 your light will stay green!

So to Summarise :

  • Imagine the 512 Channels of DMX as 512 Milk Bottles.
  • Each one can contain up to 255 units of milk (The Value).
  • For every unit of milk added to the bottle it can make your light do different things or if you fill it up between xxx units and xxx units your light may activate one function like a colour change.

From now on we'll talk about these imaginary milk bottles as Channels and the contents of the bottles as Values.

So how does your light know what channels are assigned to it? Well this is what we call Addressing in DMX every channel is fixed so imagine 512 milk bottles lined up in a row every single one has a number on it in order 1 to 512, rather like a street with houses that all have an address.

Your light needs an address so when your DMX Control Software or Hardware sets the values of a channel your light will respond (fills up a bottle and your light responds to that amount depending on how its programmed).

Your light will say in the manual it needs a certain amount of channels to operate for example let's say 6 but how does your light know which 6 channels out of the 512 it needs? It needs to know where its main address is within the 512 that's what you set on the light either with the display or using Dip Switches. Imagine your light being a property developer it's address is the first house it buys but it needs 6 to work so it buys 5 more next door to it's first, YOU decide the main house it buys by setting it's address then if its a 6 channel fixture it will automatically own the next 5 houses!

So again to Summarise :

  • Your light needs a place to live along the street of 512 channels
  • Your manual will tell you how many channels it needs to operate
  • When you set the address your light will automatically know the next amount of channels are for it so that's in our example 1 (The adddress) and 5 more channels making 6 Channels altogether!

So if it's that simple then what's all this creating fixtures and profiles for say FreeStyler DMX all about?

Basically adjusting the values manually on older DMX hardware involved a simple slider you tell that slider what channel it is then as you raise the slider up its raising the value of that channel up to 255 (or filling that milk bottle!) it's that simple but you needed to know what value did what to make it faster to program, DMX Software can do this by presenting you with Graphical buttons, sliders, positioning controls and colour pickers etc etc this makes your work flow so much easier but guess what? Every DMX Unit is different, How does your DMX Software know that to raise the 2nd channel (i.e. the second house it owns) to 255 makes your light go green or how does it even know if your light can even go green? That's where building profiles comes in…

Your Software is simply raising values up and down on different channels simple!

But to make things much faster it has ways to do things to make your life easier take for example your light has 20 different colours your software doesn't know how many colours it can do or what channels and values it needs to set and this is how fixture profiles work, Fixture profiles simply tell the software if you want your light to go green when you press green then set this channel to this value! Simple! Then because you've told your software what it needs to do to do that then every time you build a show it takes one click rather than 5 each time! and that's how you can create big shows much faster with DMX Software because the DMX software is giving you other ways to adjust these values (Filling these bottles) but you just need to tell it what to to do that!

So to recap :

  • DMX Software and advanced 'Hardware Consoles' can speed up the time it takes to create shows.
  • But they don't know what lights are connected and how it that light operates
  • Fixture profiles are your way of telling the software/hardware what to do to make the light do the action you have asked!
  • Without them the software/hardware can't operate your light!
the_very_simple_guide_to_dmx.txt · Last modified: 2013/08/25 20:00 by djsupport