DMX Multicore

[TomLyall]

Thanks guys, any comments appreciated...:)

[paulears]

what's it for? 16 DMX universes seems a little extreme? If it's less universes - maybe just 2-4, I'd go with some sort of central hub type distro, with just those four cables coing back to the desk. This way you'll keep the actual individual runs as short as possible. I guess in a conventional theatre style show, then on stage, near to the power distro is probably best?

[TomLyall]

Appologies, my poll options were a little confusing, I am only planning on having 4 DMX lines, combined with power to the control end. The '16a' refered to a 16amp Ceeform.

 

Thanks,

 

Tom

[Adrianfreston]

I have used both options. But prefer to have the "drum" (or in most cases now the road case) at the "stage" end. No point in having extra clutter at the desk is there really.

 

Also why carry the snake all the way to the desk when the truck is normally at the stage end of the building!

 

Always pull out the the destination was a rule I live by means that putting the stuff away is more logical. Also if you have pull throughs (pipes and the like) the pulls are usually run in that way so you pull the snake up on the rope and then, at the out, pull the rope back into the pipe with the snake.

 

There you go.

 

Adrian

[timmath]

neither!

 

Get a decent flight case with winding posts and "figure of 8" it into that. I have always found drums a pain in the arse - especially when dragging it though a muddy field!

 

You may want to consider for future expansion and strap an decent quality (TMB Procable for example) ethernet line down it too.

 

Regards

 

Tim

[SceneMaster]

I may be being dumb but are you running the power and the DMX in one multicore? Just isn’t there going to be interference between the DMX and the power… and secondly the multi would have to be mains rated and it can’t be good for DMX signal to be sent down mains cable (well can’t be very reliable over long distances). Or are you just creating a bundle to go on the drum with the power and then a data multi taped together? But even then won’t the power interfere with the DMX interfere with each other, unless the data multi is well screened…?

 

Sorry if this is a really dumb post I am just a little confused… :)

[Adrianfreston]

No I don't put them down the same multi.

 

I put data on a multi and keep the mains seperate, for screening and safety, however I am told in an other post that looks very much like this one, that there are no regs about it. But hey, I am not sure I care if there are regs for or against it, this is the way that all of the lighting companies I have ever worked for do it.

[Freddie]

I think the second option (DMX down DMX cables, power down power cables, then the whole lot down some sort of sleeving)

[Adrianfreston]

Sleeving just adds cost and nusance factor. I suspect the only option you would end up with would be that nylon black net stuff. That stuff just snags on every thing and any thing it can. Forget it just loom it, its a hell of a lot cheaper and you can make any loom you want.

 

I personally keep Data to Data and Power to power, no screwing up then!

[paulears]

not really dumb - the theory is that cables do 'leak'. especially those carrying signals with content approaching squarewaves (like DMX). All audio text books tell you to cross mains and signal cables at 90 degrees. In practice, they tend to all go the same way and lay alongside. I've not had any snags with running mains down a cable taped to an audio multi. I've even stuffed DMX down an unused pair, even though it isn't the right way to do it due to impedance concerns - damn touchy thing, DMX.

 

On the mains/signal multis, each internal type is separated by appropriately rated sheathing. There is available screened mains cable for the purests, but I've never actually handled any.

 

If you have a look at cables on www.cabford.co.uk, they give you nice pictures of what the inner of their multicores look like

[TomLyall]

SceneMaster, the type of thing I'm talking about is specifically made for the purpose, like this... http://www.klotz-ais.com/lshop,showdetail,...DMX,HD04,,,.htm

 

Anyway, this ones out the window in my opinion anyway, for the moment, the price for the cable alone is silly! I'm just going to run the cables seperately for the time being.

 

Thanks for your advice guys. :)

[SceneMaster]

Yep, I wasn’t suggesting that DMX should go down power (it would sort of work for short maybe a metre or so but over large distances very unreliable) or power down DMX (now that would be crazy :o I don’t even need to explain why that is :o )… I was just clearing that up in my original post on this thread… :)

[Guest lightnix]

Having the drum at the desk end of the business was one of my earliest mistakes. Honestly: it will only get in the way and you'll get rapidly sick of it. Keep it at the stage end, out of sight and out of mind.

[Mark Powell]

Multicore case at stage end, case with upright inserts to 'figure of eight' the cable into, cut outs on sides of case so cable can be run and lid closed.

Our multicores (as standard, some have more) have two 16A ceeform power cables, eight DMX lines, two comms lines, two ethernet lines. All taped together at regular intervals, not sheathed or covered in the black nylon webbing.

 

 

Please feel free to email me if you have any other questions.

 

 

Mark

[Barney]

Depending on the type of work you do, it would depend on which end was likely to get 'moved' the most. If the control position is likely to change, or if you need to run the desk into the auditorium, put the drum at the desk end.

 

If the control point is likely to be fixed (more often than not), put the drum on the stage end. This also allows you to re-run the data cable round the stage if it is likely to trip people up / get unplugged by someone else / get run over by a heavy truck with sharp wheels.