WLED DMX Output

Configuring DMX is a bit more complicated than just using pixels. Essentially WLED treats a group of 3 DMX channels as a single pixel (having a Red, Green and Blue channel). Some DMX fixtures with a single light just have the 3 channels, while others may have multiple channels for multiple lights. Other DMX lights have extras channels used in addition to the RGB channels for setting various modes and often these lights won’t seem to work if you don’t configure these other channels correctly.

Often DMX fixtures can be configured for different channel modes giving various options in operations. And unfortunately the documentation (especially for cheap DMX fixtures) is often lacking (or non-existent) in details and this greatly adds to the frustration of setting them up.

To start you need to determine the channel mapping of your fixtures. For a simple RGB fixture this can be:

• Channel 1 = Red,
• Channel 2 = Green,
• Channel 3 = Blue.

Note that all the DMX fixtures connected to a single WLED controller must have the same DMX channel map. 

If your fixture needs any channels set to enable functionality then you need to account for this. For example some lights have a mode channel that must be set for a value before the light will work or a brightness channel that must be also controlled.

Next you need to configure the addressing of the fixtures. While the first fixture can start at any DMX address, the successive fixtures must be addressed sequentially (for the same simple fixture the first one is at DMX address 1, the second one is at DMX address 4, the next at DMX address 7, etc)

Next in the LED Preferences set the “LED Length” to the number of DMX fixtures you have connected (if each fixture has a single RGB channel) or the number of RGB channels you have connected in total.

Now go to the DMX Output page. Here you need to set the following:

• Channels Per Fixture = Set this for the number of channels your DMX fixture needs.
• Start Channel = Set this for the beginning address of the first fixture.
• Spacing = Set this for the number of channels (same as “channels per fixture” setting)

Under Channel Functions you will now see a group of channels (the number of which match what you set above in Channels Per Fixture). Set each channel to match what your fixture requires. The options include:

• Set To 0 – Always send 0 on this channel
• Set To 255 – Always send 0 on this channel
• Red – Sends the Red value on this channel
• Green – Sends the Green value on this channel
• Blue – Sends the Blue value on this channel
• White –  Sends the White value on this channel
• Shutter (Brightness) – Sends the Brightness value on this channel

You may wonder why there is an setting for Spacing between start channels which seem to duplicate Channels per fixture. It lets you pad the number of DMX channels assigned to the fixtures to move the start channel to an easier to figure out channel for fixture programming.  Lets say your fixtures use 7 channels, this would mean the start channels would be 1,8,15, 22, etc. You could change the Spacing between start  channels to 10 and then the start channels would be on more easy to figure out numbers (1, 11, 21,31, etc). Might make it easier for you, note that it does burn up DMX channels.

Something that is quite helpful is the Channel Map button. It shows you what values are assigned to what channel  and in handy to confirm things match what you need.

Note that as far as I can tell you can’t use the pixel output at the same time as you use the DMX output.