Embarassing DMX Questions

[DarSax]

Yeah, all right, I have a confession to make: I still don't really know how that whole "DMX" thing works, even after two years of being a Lighting Director.

Hokay. First off, conventional lights. Light power -> dimmer -> console? DMX Interface? The last step is the one I don't know. I know at school we have a separate box the DMX connects to, which connects to the board, but then again my board is so antiquated that I'm not sure if this is the same with all boards. Could someone tell me basically the connections to control conventional lights?

Second off, intelligent lights. In order to run them on a board, do you basically have to connect them all in series (in the end) in order to connect them to the one or two outputs in your console?

Third off, DMX/XLR. I know that DMX is what you really should use for intel lights, but I know that we've often used XLR cable instead, and that it's the same. I'm right on this one, correct? Or am I being forgetful, and DMX has 5 pins to XLR's 3? Heh.

Yeah, I've been wondering these things, but a bit too embarassed to ask, because I'm sure the answer is simple. By the way--I don't need the whole explanation of DMX, channels, etc; I just want to know how one would hook up a setup if one was starting from scratch.

Thanks, and stuff. !

[BillESC]

I'll start at the bottom of your post and work my way up.

Mic cable is rated at 80 Ohms and DMX cable at 120 Ohms. In limited situations, i.e. small number of fixtures or less than 100' of total cable runs mic cable will work. "Real" DMX is designed to operate on 5 pin XLRs, however, at this time only 3 of the conductors are used and many manufacturers have adopted the use of 3 pin XLRs to save money. If the future all five conductors will be utilized as the next generation of intelligent fixtures will be sending status information back to the controllers.

Yes, intelligent fixtures are daisy chained one to the next to the next with one line back to the controller. You can also use opto-isolators to split the DMX data into two or more trunks.

There are two ways to integrate conventional (or analog) fixtures for operation via a DMX console. First if you already own analog dimmers, you'll need a Black Box. A Black Box will translate the DMX signal into an analog signal the dimmers will recognize. If you don't have analog dimmers you'll need to obtain DMX dimmer/relay packs which respond to DMX to control conventional fixtures.

[jonhirsh]

You can daisy chain your movers but affter about 26 devices you need to put them on another liine this inclueds dimmers one dimmer rack = 1 device.

DMX cable vs. Mic cable. Does an $5,000 show seem worth the price of getting the right cable.


Power Setup

Disconnet ->Dimmer -> Cable To Fixtures
Distro -> Cable To Movers

Data

Console ->DMX -> If dimmers are analog (DMX to AMX convertor) -> Dimmers.

Console -> DMX -> Mover 1 -> Mover 2 -> etc. -> Terminatior on the last mover.


JH

[DarSax]

I'd add little "thank you's" to each of your post, but that'd get visually distracting. Thank you very much. (I finally know what isolators are for! Excellent!)

And it'd make sense that we'd need a 'black box,' we have a hard-patch system and the original board was, of course, an analog board. That makes sense, excellent.

Since you had mentioned it, JH, I have another question, about power. What do you guys mean by distros? I've heard that dimmers (unless they're back-packs) are usually powered by the rack and need special power. Then again, from what you were saying, the distro is related to moving head fixtures. I'm ah, a-very confus-ed.

Thanks again though, you've cleared up a ton of my confusion.

[jonhirsh]

Distros are used to take 3 phase power and break it down to usable power for a moving light.

For example I have a 400 amp disconnect i have 20 moving lights the movers are a mixture or 20 and 15 amp, So i have differnt modules that decide which amount of power they are and they have plugs on the back they could be twist lock or soca or edison. based on what amp of power is necessary


Dimmers usualy have power put directly to them as in a sense they are there own distro they just dim the out put of power. based on a console.

check out this site for some pictures of distros
http://www.christielites.com/rental2...=0&totlines=-1

[zac850]

In slightly planer englsih, a distro DISTRObutes power.
The power comes into the panel, and the distro box distrubtes the power around the theater to the movers.

[DarSax]

Heh, now I gotcha, thanks. What type of cable goes from the distro to the lights? Just regular AC cable? (I ask, because I don't know where/if we have a distro, we've just used our standard sockets, wall and ND's.

[cutlunch]

DarSax The cable used would be AC cable. But whether it is single run cable, ie one cable per plug outlet or a multicore cable that carries many electrical circuits in the one cable depends entirely on how they wired your theatre. It could be a combination of both. Eg mutli-cable to a lighting bar. Single cable to single side of stage points.

[DarSax]

Gotcha, gotcha.

In the next few (probably this one) days, I'm going to try and write out the steps to hook up an intelligent light setup, if one/some of you all would be so kind, I'd appreciate it if you could tell me where/if I'm missing steps or if I'm confused about something.

Thanks so much for all of your help, again!

[DarSax]

All right, I included a diagram of how to hook up intelligent fixtures, to the best of my knowledge. Is this correct/could someone answer the questions that are in the image? Thanks