Tag: merging

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Gateway: sACN and Art-Net implementation

The sACN (streaming ACN) protocol is supported in Artistic Licence ethernet products. The differences between Art-Net and sACN lead to some minor clashes which this document seeks to clarify.

Universe numbering

In Art-Net, universes are called Port-Address and number from 0 to 32,767. There are 32,768 unique numbers.

In sACN, universes number from 1 to 63,999. There are 64,000 unique numbers. The standard reserves the values of 0 and 64,000 to 65,535 for future expansion.

Clearly there is the potential for confusion over the number ‘0’. If a universe is set to ‘0’ and the sACN protocol is selected, Artistic Licence products will use a universe value of ‘1’ instead.

Merging and arbitration

The sACN protocol uses a concept called Component Identifier (CID) as a method to optionally distinguish unique streams of data, and a concept called Priority as a method to define the priority of a stream.

 

The following table defines how sACN packets A & B are arbitrated or merged when directed to same universe.

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Developer: Art-Net – Multiple controllers

Art-Net allows and supports multiple controllers on a network. When there are multiple controllers, Nodes will receive ArtPolls from different controllers which may contain conflicting diagnostics requirements. This is resolved as follows:

  • If any controller requests diagnostics, the node will send diagnostics. (ArtPoll->Flags->2).
  • If there are multiple controllers requesting diagnostics, diagnostics shall be broadcast. (Ignore ArtPoll->Flags->3).
  • The lowest minimum value of Priority shall be used. (Ignore ArtPoll->Priority).