Two DMX Controllers

[khargy]

I have both an Open DMX USB controller, and and an CHAUVET Obey 10 for controlling my DMX lights -- is there anyway to hook up both controllers to my DMX network so I can use them both at the same time?

[dmcole]

First, welcome to DIYC.

The only way you can use both controllers is to build two different "legs" to you DMX network, with different physical devices attached to each leg. I don't believe there is a way to "meld" the two signals into one (though I suspect that such a device could be built -- not easily, but it could be done).

Neither of those controllers would be particularly useful in a holiday lights show -- the Open DMX dongle is prone to dropping frames in the 50ms timings we tend to use, while the Chauvet is designed for stage shows.

HTH.

\dmc

[DynamoBen]

First, welcome to DIYC.

The only way you can use both controllers is to build two different "legs" to you DMX network, with different physical devices attached to each leg. I don't believe there is a way to "meld" the two signals into one (though I suspect that such a device could be built -- not easily, but it could be done).

The only way to use two DMX sources on the same wire is with a merger. This (http://www.dfd.com/221e.html)is an example of a commerical merger.


Neither of those controllers would be particularly useful in a holiday lights show -- the Open DMX dongle is prone to dropping frames in the 50ms timings we tend to use...

I've been using the OpenDMX dongle for 5 years and have never seen this problem. The refresh rate for the OpenDMX in Vixen is 33hz which means your timing needs to be 30ms or more.

Are you seeing this with your dongle, if so let me know it might not be functioning correctly?

[khargy]

Well it looks like I can't just splice two signels together -- I guess that would be too easy -- I just wanted to do that for fun so it's no big deal.

Christmas 2011 will be my first light display so for now I'm planning on keeping things simple with the idea of making things scalable in the future.

So I got the Open DMX USB controller just because it was the cheapest and I wanted to write my own asp.net app and it had an open API. I haven't had any problems w/ it but I haven't done anything taxing either.

The CHAUVET controller is great for setting things up and testing the lights and connections so I don't have to worry about computer problems/bugs. Also after my fiance saw some of the tests I've been doing she wants me to setup lights at our wedding in November. Altough you can't do any elaborate music timed sequences it is able to basic scenes and fades and whatnot. It'll be much easier to setup and for someone to control then say a computer.

[DynamoBen]

Over the next year I think you will see a push toward ethernet, which makes scalability a non-issue. In addition with an ethernet node you could combine both of those interfaces onto 1 cable which keeping cabling costs fairly low. The downfall to ethernet is distance, but for most this isn't an issue.

[Matt_Edwards]

Also after my fiance saw some of the tests I've been doing she wants me to setup lights at our wedding in November. Altough you can't do any elaborate music timed sequences it is able to basic scenes and fades and whatnot. It'll be much easier to setup and for someone to control then say a computer.
Getting married and playing lightie at the same time, that's a challenge!;)
Hope the day goes well.

BTW, I too used the Open DMX Widget for my first year. I blew the RS 485 chips, but that was more related to my set-up not the device.

[Entropy]

If you wanted to build your own "merger" device, you would probably need a microcontroller with 3 UARTs - two for DMX reception, one for DMX transmission. Unfortunately this drives a pretty beefy system.

Unless you wanted fancy merging logic (channel A is the maximum of channel B from universe 1 and channel C from universe 2, etc), it would be easy just to have two fully separate and independent DMX universes.

[DynamoBen]

The most common merger protocol is HTP (highest takes precedence) on a channel by channel basis. In code you would need to compare each channel in each stream and send the highest of the two.