Protocols Explainer

In Pathscape Create, fixtures can be patched to DMX or eDMX (Art-Net, sACN or KiNET).

DMX - A DMX universe which contains 512 channels; most fixtures will use multiple channels depending on their functionality. For example, a standard RGB LED will use three channels, one for red, one for green and one for blue, whereas a pure white LED will only use a single channel; one for intensity. Each channel can go from a value of 0-255, which then determines the intensity of that parameter.

Each fixture in your project will have two bits of information that are essential for Pathscape Create to be able to drive the fixtures; a start address, and a footprint. The start address will simply be the first channel that the fixture takes, and the footprint is how many channels the fixture needs; for example, an RGB LED will have a start address of 1 and a footprint of 3, so will listen to channels 1, 2 and 3. The next fixture will have a start address of 4 and a footprint of 3, and will listen to channels 4, 5 and 6, and so on. For a single RGB LED, if the Controller were to output 255, 0, 0, the fixture would turn red. If we adjusted the output to be 255, 0, 255, the fixture would be purple. With DMX, all channels in the universe are then sent out on every refresh, allowing for smooth transitions from one color to the next and enabling dynamic lighting effects.

eDMX (Art-Net, sACN, KiNET) - eDMX is, in principle, the same as DMX. It works with the same concepts of universes and channels, each controlling a different parameter for a fixture. However, the protocol is instead output through the Ethernet port of the Controller, which will then be converted back into DMX data by an eDMX node on the network.

There are some key differences between each available eDMX protocol:

  • Art-Net - Art-Net, developed by Artistic Licence, will broadcast up to the first 30 universes. If more universes are output, then the protocol will switch to unicast, therefore sending the data directly to the IP address of a node that will output the Art-Net data. To do this, the Controller will send out a ArtPoll message. Each node would then respond with information on which universe(s) it is looking for, and the Controller would then send just that universe to that node. Art-Net also supports RDM in the same way as DMX.

  • sACN - sACN, developed by ESTA, uses multicast to communicate with the nodes. This means that each node will only have to listen to the specific IP address for the universe it takes its data from, which reduces network strain compared to broadcast for Art-Net. sACN can also support HTP merging depending on the node.

  • ssACN - Pathway Secure Streaming ACN, an authenticated version of ANSI E1.31 sACN that ensures the authenticity of the sender, verifies the entire data packet is integral from source to receiver and includes a method to prevent replay attacks.

  • KiNET - KiNET, developed by Philips Color Kinetics, is a system developed to combine power supplies and eDMX nodes in one. Instead of X number of universes added, power supplies are added from the network which provide a certain number of ports which can then be patched to.