DMX Merger

[JohnK]

Hi all,

 

Has anyone out there got any experience in using a DMX merge with Moving Lights? I've got a gig coming up where I need two control positions controlling the same rig, and since I already have 1 desk, I only want to hire 1 more.

 

Thanks

John

[gareth]

To clarify, John .... are you talking about a situation where you have two desks talking to the same bunch of lights (e.g. a stalls/studio remote desk and a main control room desk), or two desks each controlling their own portion of a large rig, but feeding it down a single set of data lines?

 

What particular kind of desks are you planning on using? Strand 500 series desks do this kind of thing quite well, I understand (never had cause to do it myself, though) - partitioning a rig between two desks for programming, then merging the two sets of cue data onto one desk at a later date. I notice Rob Halliday has joined us recently - he'll be the guy to talk to if you want more information on this particular feature of Strand consoles.

[andystone]

It really depends on whether you want the two consoles to control the same lights or different ones.

 

If different ones then it is easy, you just only patch in the fixtures you want to control on each console.

 

If you want both consoles to control the same moving lights then things get tricky as most DMX mergers work on an HTP basis, so whichever desk has a parameter at the highest level will take control.

 

There isn't really a neat way around it, apart from using consoles that can be networked together, but you would still need to assign movers to each desk. What you really need is one main control desk and then the second 'desk' would be a remote control unit to the main one, thus whatever you select on the main console can also be addressed from the remote, if they both select the same mover they can both address the same parameters, but whichever moves them last will have control

 

Only other way to do it is to use a DMX merger with LTP merging, so again whichever console addresses a parameter last will take control, but of course you will end up with two sets of data.

[mac500]

I assume he means to control seperate parts of the rig but still keep it on the same DMX line I assume?

[colinmonk]

How many data lines do you invisage needing to control your rig? Could you get it on one?

 

and what desks are you planning to use?

[Neil Vann]

As everyone else says, it really depends on how you want to use the 2 consoles.

 

The hardest is to want to use both consoles at the same time talking to the same lights. In this case you really need to use something like the grandMA consoles, where the 2 consoles can network together and calculate what to tell each fixture to do BEFORE it is turned into DMX/ArtNet etc. If you try merging the DMX from 2 seperate consoles both trying to talk to the same fixtures, and use LTP, there can easily be a conflict where they are each telling one parameter of a fixture to do different things. This means that in reality it will try to go red, blue, red, blue, red blue as alternate DMX frames are recieved.

 

If you want to use 2 console to talk to different fixtures, use an HTP merge of the 2 consoles with only the fixtures patched that you want to talk to. Even though you may not have patched fixture 1 on console 1, this console is still sending 0 level data on the DMX channels of the unpatched fixtures, so in LTP land this still has the conflict between to 2 consoles.

 

The simplest one is to have 2 control positions of the same rig, but for use at different times. In this case, run DMX from console 1 to the stage, then from console 2 to console 1. When you want to use console 2, unplug console 1 and plug this DMX cable into the one from console 2.

 

 

Hope this helps, and isn't too confusing.

 

Neil

 

Neil Vann

Technical Sales and Support

AC Lighting

 

neil.vann@aclighting.com

[JohnK]

To Clarify what I'm trying to do:

 

I have a gig where the venue is divided into 2 sections. I need to have a desk in each section to control that area. However there are a couple of reveal sequences where both sections need to be controlled from one desk.

 

Ideally doing something with the DMX lines would be good, as I have a Pearl already, and don't want to hire 2 extra desks.

 

The rig will actually run on 2 DMX lines, one for the statics, and one for movers, The statics line I can deal with, as that is a standard HTP DMX merge, it's the line for the movers that is causing me a headache at the moment.

 

Thanks

John

[gareth]

To Clarify what I'm trying to do:

 

I have a gig where the venue is divided into 2 sections. I need to have a desk in each section to control that area. However there are a couple of reveal sequences where both sections need to be controlled from one desk.

 

Ideally doing something with the DMX lines would be good, as I have a Pearl already, and don't want to hire 2 extra desks.

 

The rig will actually run on 2 DMX lines, one for the statics, and one for movers, The statics line I can deal with, as that is a standard HTP DMX merge, it's the line for the movers that is causing me a headache at the moment.

So you aren't going to want to run both control positions simultaneously? Sounds like the solution could be a LTP merger of some sort. Or even a simple DMX A/B switcher - just click over from one desk's output to the other when you move between rooms. (Actually, hainvg read your reply again, it might not be quite that simple - are you saying that sometimes you'll need both areas controlled from a single console, and at other times you'll need separate consoles controlling their own areas simultaneously? If so, then I guess it's still possible with simle DMX switching, but it'll need to be more of a 'matrix' type of operation rather than a simple A/B switch.)

 

AC Lighting's ChromaQ range includes some useful little black boxes that do this kind of thing ... or there's Artistic Licence's range of DMX processing units.

[colinmonk]

I would suggest not using a DMX switch to change your control options, basically because your going to have to make sure all the values are the same on both consoles before you switch, or end up with an interesting effect while the kit changes position to match the new output.

 

DMX Merge would do I would think, only patch what you need on the second desk and patch everything on the first, if it was all LTP merging then the 1st desk will overide outputs of the second for your reveals and then operation can resort back to the independent desks for the continuation.

[peter]

Couldn't you just MIDI the two desks together, but have them controlling different parts of the rig?

[Jivemaster]

XTBA did once offer to custom programme a merge for me to do similar, but you cannot hire them custommed.

[johnhuson]

If your planning on using two Pearls then I reckon your best bet is to connect them together using MIDI. All you need to do is set Desk A to Master and Desk B to Slave in the Midi options in the system menu (think thats right from memory). Then when for example Playback 1 is raised on Page A the same playback is controlled on the slave desk.

 

In your situation you could have all the playbacks you want just Desk A to control on say roller page 1, all the playbacks you want Desk B to control on roller page 2, and then when you want desk A to control B, program playbacks on roller page 3 of both desks and Desk A will control both. By doing it this way you avoid Desk A controlling Desk B when you have the room split, but when you flick to Page 3 it will control both desks. Although this will limit the number of playbacks you will still have 150 playbacks that only desk A controls, 150 playbacks that desk B controls and 150 playbacks where desk A operates both consoles.

 

This should work, but can't remember if the playbacks will work on desk B once it is set to slave, so you may have to quickly switch desk B into slave just before the reveal.

 

Hope all this makes sense, if not feel free to ask any questions, either on here or by PM/E-mail.