ArtNet send single Channel

vvvv beta question
#1

Hi ArtNet users, Devs,

When I send DMX values over ArtNet with DMX (Network Artnet Sender) , I can only send full universes. Is there a way of sending only active channels on a universe, not the full frame? Ideally with a spreadable DoSend Input of the DMX ArtNet node. Does anybody know about a specification regarding this? Does ArtNet allow to send only some values?
Thanks!
Eno

#2

Hi,
ArtNet is DMX “multiplexed” and the DMX protocol is sending the all 512 channels in each packet. I think it’s not possible to send only a few channels.
Best
Mehdi

#3

Thanks for that confirmation!
After my post here I figured from the ArtNet standards definition that the ArtDMX function always sends DMX512 data, which is essentially one full DMX universe.

This poses questions how to use one universe with two ArtNet nodes without overwriting values …

Can I address fixtures from two machines on different channels in the same universe without creating overwrites?

Thanks!

Eno

#4

Can’t you change the universe on one artnet node?

#5

Yes, but with a temproal difference I want to control the same fixtures from different machines. Or rather: Sometimes I want to control some fixtures from a specific machine, while usually they are controlled by a regular light desk.

#6

Hi Eno,

If I understand well your goal, I think there are two cases:

  • only one machine > only one artnet node by dmx universe, you do normal slice operations to mix your values before the artnet node.

  • two or more machines > If you want to “merge” values, I think you need to chain your machines.
    machine1 >>> machine2 ( receives universe and modifies it ) >>> artnet receiver

Best

Mehdi

#7

you need a DMX merger for that, a quick googling comes up with lots of boxes, the top one was this one: http://www.strandlighting.com/index.php?src=directory&view=products&srctype=detail&back=products&refno=23

#8

or you could use a device like the Datagate from Enttec: http://www.enttec.com/?main_menu=Products&pn=70044

EDIT: this will give you an artnet to dmx box as well as a merger (it seems, I have not tried it)

#9

(at least some) artnet-nodes support merging with ltp (latest takes precedent)
that might be what you want.

// ah, almost the same answer as sune

#10

Thank a lot for this helpful information!
XE

#11

I’m pretty sure that PixelMad, an osx LED mapping app only sends channels that have changed, and as a result can handle 100’s of universes of channels, a spreaded send would be really useful!

#12

Hi,
After playing a bit with Artnet in vvvv, I find merging values in vvvv is great because you can use all animation nodes where “classic” mergers allow only HTP/LTP.