Control/Dimming - Dimmer Wiring

[marcusianl]

During the renovation at our school's theatre this past year we received a new Sensor+ Dimmer rack. However, when wiring our FOH catwalk, they didn't run new Dimmer lines, they just ran new cable through the existing ones, so we only have 6 Dimmers on our catwalk (although we have 18 instruments and 24 outlets). Is there any way to increase the number of controllable dimmers without running more cable? I saw something on ETC's website about a Dimmer Splitter. Would that do the job?

-Marcus

[pdk]

It depends on what kind of fixtures you have and what your budget is. Dimmer doubling basically splits the power coming out of the dimmer into two independent 77V circuits. As far as I remember, dimmer doubling works only with ETC fixtures and you have to switch the fixtures to be doubled to a special 550W/77V HPL lamp and a special kind of twistlock connector in addition to buying the dimmer doubler itself. So basically yes, it can work in some cases and is cheaper than running new cable, but depends a lot on your exact setup. It only works on US supplies (115V 60hz) as I recall, so that might limit it as well. But generally, if running more cable is not an option because of cost or the space, then dimmer doubling can work.

[Footer]

Its called dimmer doubling. Essentially, you put 77v lamps in the lights (must be S4). You then attach a multiplex two-fer to the lights, and plug it in. The dimmer has to be told that it is multiplexed. You can two-fer off a multiplex as well.

Now... that being said... I hate dimmer doubling. I can not tell you how many channel checks I did in college after a 300-400 instrument hang and here "pop, pop" with 77v blowing in lights hooked up to 120v. If its not organized well, it can become a real headache real fast. It is however much cheaper then running new dimmer lines.

[derekleffew]

...and is cheaper than running new cable, ...

...It is however much cheaper then running new dimmer lines.

Disagree with the above as it depends on the circumstances. If the dimmers already exist or a less than fully-populated rack, and space available in the conduit, dimmer doublers would cost more, when one figures the cost of the lamps, connectors, DimmerDoubler, and the forever hassle of patching, non-standard lamp, etc.

#12 (or #10) THHN is inexpensive and I'd rather pay the labor once to pull it than for the rest of the dimming system's life (10-30 years?) deal with dimmer doubling.

[JD]

Have to agree with Derek. There are limits to the number of runs you can pull through a given conduit size, but even having additional conduit installed may be cheaper. Pipe is cheap, and unless they have to go through a block wall, they can simply duplicate the current bends and path taken. Depending on the school and the turnover, newbies would have to have DD explained to them, otherwise the consumption of lamps may go through the roof.

[marcusianl]

We are running on S4's and it's a pretty simple setup (only about 50 instruments hanging currently) but I'd like to be able to avoid the hassle and paperwork of requesting new lamps, different connectors, and the doublers, so maybe I'll ask about wiring new dimmers. Would it be a horrible idea to run the cable along a wall without being in an actual wire tube? The way our space is set up we could potentially run cable through a hallway into our FOH catwalk. It would probably be about a 200 foot run, maybe a bit more.

[jmabray]

You would be in violation of your electrical code not running it in EMT (Empty Metal tube) AKA Conduit. Theatres get away with running extension cables from one outlet to power a fixture because it is a temporary set up. When you get into running circuits like you are talking about, you are moving from temporary to permanent and it must be done according to code.

[marcusianl]

Figured as much. I highly doubt we'd be able to get the school to contract someone out to run the wiring seeing as the work order for the renovation that just happened was placed in 1992. Gotta love bureaucracy :/ For now I guess we'll just have to deal with it. Thanks for the help everyone

[derekleffew]

Weren't you the one asking what to buy given a windfall of a few thousand dollars? While not as glamorous as moving lights, investing in infrastructure is always good. I'm guessing adding six more dimming circuits could be right around $1500-$2500.

I realize there may be politics and procedures involved. In some cases it may be possible to buy equipment, but not improvements to the building, or the reverse.

[marcusianl]

Yes, I am the same person, and that's exactly my dilemma Derek. My administrators don't know that being able to control my lights in sets of 2 or even 1 as opposed to 4+ is far more important than new toys to play with, and seeing as I'm only a student I can't exactly tell them they're wrong. They respect that I'm one of the few people in the school who know how to run things, but I still have to bow to their authority. They honestly believe that the renovation we got this year transformed the space into some magical world where anything is possible, all you need are the fixtures. While the renovation did a whole lot of good (we had about 3 working dimmers and one working mic) it wasn't the best we could've hoped for considering how long the wait was. Anyways, I'll talk to my Director/Department head and see if the Admins would let more infrastructure work fly, but I doubt it. They want to see pretty things, not efficient things.

[STEVETERRY]

Disagree with the above as it depends on the circumstances. If the dimmers already exist or a less than fully-populated rack, and space available in the conduit, dimmer doublers would cost more, when one figures the cost of the lamps, connectors, DimmerDoubler, and the forever hassle of patching, non-standard lamp, etc.

#12 (or #10) THHN is inexpensive and I'd rather pay the labor once to pull it than for the rest of the dimming system's life (10-30 years?) deal with dimmer doubling.

I am somewhat confused by this thread. Dimmer doubling gives you 2X the number of controllable circuits with no impact on the infrastructure--just the cost of the dimmer doubling twofers. The cost of those twofers is trivial compared to more dimmers and more circuits in conduit.

The stated problem can be solved most efficiently by the addition of dimmer doubling twofers and moving to 77 volt HPL fixtures.

As to the "pop, pop, pop" post in this thread, if the wrong connectors are used on 77V fixtures it is both a Code violation and a design flaw in the system. This falls into the "really dumb" category. In a properly designed system (like nearly every Broadway show, for instance) it will not be possible to apply 120V to a 77V fixture.

Dimmer doubling gives you twice the number of controlled circuits for a given number of dimmers and branch circuits. This sounds like the ticket in this application.

ST

[Footer]

As to the "pop, pop, pop" post in this thread, if the wrong connectors are used on 77V fixtures it is both a Code violation and a design flaw in the system. This falls into the "really dumb" category. In a properly designed system (like nearly every Broadway show, for instance) it will not be possible to apply 120V to a 77V fixture.

Yep, they had the famous stagepin to twist adapters on all the the dimmer doublers. I never liked in that way, it drove me up the wall.

[SteveB]

During the renovation at our school's theatre this past year we received a new Sensor+ Dimmer rack. However, when wiring our FOH catwalk, they didn't run new Dimmer lines, they just ran new cable through the existing ones, so we only have 6 Dimmers on our catwalk (although we have 18 instruments and 24 outlets). Is there any way to increase the number of controllable dimmers without running more cable? I saw something on ETC's website about a Dimmer Splitter. Would that do the job?

-Marcus

A non-traditional approach. Since the school is willing to purchase gear, as opposed to paying for an electrician, (with a note that while I like the Dimmer Double option, I hate the complexity in an in-house system, where stuff moves around. I also think that getting an electrician to add additional circuits, assuming the rack has spares, is the best option), possibly do the following:

1) Convert the FOH Catwalk 6 dimmers/3 Sensor modules to Sensor direct circuit breaker modules. Now all 6 circuits on the catwalk are constant power @ 20 amps, single phase.

2) Purchase 3 - Lex Products Anaconda 6x800w dimmer packs. Power the packs via the constant power outlets. Ea. dimmer handles 800 watts, which is sufficient to handle a 575w Source 4 (but not a 750w, if continuous load factors are met). Each pack requires 2 - 20 amp feeds, single phase. This would give you 18 x 800 watt dimmers at the position, for the 18 existing units.

3) Run your own DMX to the packs.

Dimming & Control: Anaconda 6 Channel 800 W Stage Pin Dimmer | Lex Products

Steve B.

[derekleffew]

...so we only have 6 Dimmers on our catwalk (although we have 18 instruments and 24 outlets). ...

...Dimmer doubling gives you twice the number of controlled circuits for a given number of dimmers and branch circuits. This sounds like the ticket in this application.

It sounds as though there are four outlets per dimmer. What happens if a 115V lamp is plugged into an outlet that has been designated as DD? What happens if two DDs are plugged into the same dimmer via two outlets? There seems to be confusion as to whether twofers can be used with DDs, and if two 550W 77V lamps per side is acceptable. Do the dimmer numbers become nA and nB or n and n+256? L5-15 twofers and cable as well as stage pin twofers and cable. Two types of lamps. No possibility of going to a 750W lamp.

I like SteveB's solution, and was going to propose something similar, but feel it also is too complex for a high school situation.

[marcusianl]

Just clarifying:

1. There are no code violations in running open DMX cable, correct?
2. Our S4's are 750w (at least they read 750 on the barrel. I've never worked with 575w's but I always presumed that the 750 indicated 750w)
3. Where would one obtain circuit breaker modules for the Sensor? Would our supplier have them?

[MNicolai]

Just clarifying:

1. There are no code violations in running open DMX cable, correct?
2. Our S4's are 750w (at least they read 750 on the barrel. I've never worked with 575w's but I always presumed that the 750 indicated 750w)
3. Where would one obtain circuit breaker modules for the Sensor? Would our supplier have them?

Though AHJ (see glossary) will take precedence, DMX can probably be run open because it's low voltage. However, there are sometimes specific ways you have to run the cabling. If you look above the plenum ceilings in places, in many cases you'd find ethernet and all sorts of low voltage data/control cables that would just be sitting above the ceiling. However, firefighters started noticed when they would enter these buildings that as soon as the ceiling burnt up, the cables would drop and become an obstacle to them. As such, now in many places it's required that these low voltage cables not in conduits be secured in some manner, be it in a basket or harness of some form. This may or many not be applicable to you, but understand that just because it doesn't have to be in a conduit, doesn't then mean you can run it however you'd like. Also, you will not be able to run it in existing line voltage conduits; if put in a conduit it would need to be run in an individual conduit containing only low voltage wiring.

Any Source Four rated for 750w, may also use 575w and 375w lamps. Also, they can use 77v 550w lamps with dimmer doubling. The only difference is in the lamp, not the fixture. If you want your fixtures to be less bright, or you can't afford to use as much power, then you would lamp down to lower wattages. Also, 575w lamps burn through deep, saturated gels far slower than 750w lamps, and they do not burn gobos as quickly as well. Likewise, if all of your Source Fours are using 575w lamps and you some of them to be brighter, you would put a 750w lamp in. Most modern Source Fours are rated to 750w, but PAR MCM's (metal cold mirrors) and Source Four Juniors are only rated to 575w, and some older Source Four products may contain lamp bases that are only rated to 575w, as that is how they were originally designed. The upgrade for those fixtures is simply a new lamp assembly.

Obtaining parts or products for your Sensor racks shouldn't be too difficult. Your dealers can probably hook you up. ETC is a well-known manufacturer, and though dealers may not keep extra modules sitting on a shelf on site, many will have easy access to them that you could order the parts you need through them. However, I do not understand what you mean by "circuit breaker" modules. ETC makes many different products for their dimmer racks that use circuit breakers. If you're referring to a Constant-Circuit module (ex. CC20 = constant-on circuit @ 20amps), then that is a module that will simply always remain active at line voltage.

Another reason to consider dimmer doubling though is if the fixtures on your catwalk typically remain there. I know a couple theatres that have their entire catwalks on dimmer doublers because they never have to worry about mixing their 77v and 120v lamps and fixtures up as the fixtures on their catwalk almost always remain there. Dimmer doubling is actually a very simple and relatively inexpensive option if the fixtures on your catwalk are often static and wouldn't move to 120v positions regularly. As such though, I wouldn't recommend only a partial-upgrade. If you are going to purchase dimmer doublers, get them for each and every circuit on your catwalk. If you have a mix of 120v and 77v fixtures up there, then there will be mistakes made in using the appropriate lamps at their respective voltages.

[JD]

Just a quick note about Dimmer Doubling:
This works because the positive half of the AC waveform acts as one channel, and the negative half acts as another. The "splitters" at the lights contain diodes, so depending on the polarity of the diode, your light either sees the positive side (channel "A") or the negative side (channel "B".) As the lamps (77v) are "effectively" seeing 1/2 the RMS (thus 77 volts) their current draw for a given wattage is double. As long as the load is balanced (equal A fixtures and B fixtures) your dimmer capacity remains the same. You should not run 2k of "A" fixtures on a 2k dimmer as your current draw would be 2x rated load on that half of the wave, and 0x rated load on the other half. Even the SSRs internally contain two SCRs and this would stress the one allocated to that half of the waveform. (Probably enough of a safety factor, but still not a good idea.)

As for plugging in a conventional 110 volt fixture without an adapter, the result would be that channel A would operate the lamp from 0 to 50%. Channel B would also operate the lamp from 0 to 50%. Operating both channels together would operate the lamp 0 to 100%. Although odd, no damage would be done.

[KeeperoftheKeys]

Just to quickly add to that:
Since Dimmer Doubling works the way it does it is no problem to plug in two doulers in paralel, as long as the total load does not exceed the max load of the dimmer.
Plugging a doubler into a doubler would be utterly pointless and lead to nothing.
Also the doubling is supposed to happen near the fixtures, so a outlet should not be doubled (ie the doubling is not supposed to happen at the rack), I don't remember why this is but it is not recommended to have long cable runs 'behind' the doubler...

[derekleffew]

... As long as the load is balanced (equal A fixtures and B fixtures) your dimmer capacity remains the same. You should not run 2k of "A" fixtures on a 2k dimmer as your current draw would be 2x rated load on that half of the wave, and 0x rated load on the other half. Even the SSRs internally contain two SCRs and this would stress the one allocated to that half of the waveform. (Probably enough of a safety factor, but still not a good idea.) ...

So I must have an equal number of fixtures on each side? Must I also run them at the same level (which would seem to negate the DD)? What if a lamp burns out, I now have an unbalanced situation--must I stop the show while I relamp it?

[KeeperoftheKeys]

The dimmer 'understands' that the signal is going to be duplexed and as such it will be varying the degree of chopping for each 'side' of the sine wave on it's own, so you can run each side at an individual level and I don't think that the load needs to be balanced either, you just have to make sure you don't exceed the max load of the dimmer.

[marcusianl]

Our catwalk lights are relatively stationary, but we have a total of 24 outlets up there, corresponding to only 6 dimmers. I'm not positive on the dimmer capacity but we run 4-5 750w lamps on them at a time and they don't trip. Would this mean that I need 24 DD's?

[KeeperoftheKeys]

Our catwalk lights are relatively stationary, but we have a total of 24 outlets up there, corresponding to only 6 dimmers. I'm not positive on the dimmer capacity but we run 4-5 750w lamps on them at a time and they don't trip. Would this mean that I need 24 DD's?

ETC say that you can only run 2 (550W 77V HPL) fixtures, one on each side, on a DD, however the rest of their documentation suggests that as long as you don't exceed the maximum drawable current you of the dimmer you could put more fixtures on there.... (though 550W@77V = 7,14A which would mean that a third fixture would @FULL already trip your fuse...)

Whatever the case is even if you get 24 DD you will still only have 12 control channels there as you are splitting the incoming channels.
But having multiple splitters will (as long as you are careful about which side you plug what into) make it easier as far as cabling is concerned....

Have a look at the documentation on the ETC website maybe that will help you....

http://www.etcconnect.com/docs/docs_...Doubler_vF.pdf

[marcusianl]

According to this the DD's can be ordered in StagePin format, correct? I'd hate to order 24 of them and be stuck with TwistLocks

Nevermind, just read the requirements. All of our fixtures are StagePin, so DD's would be useless.

[JD]

So I must have an equal number of fixtures on each side? Must I also run them at the same level (which would seem to negate the DD)? What if a lamp burns out, I now have an unbalanced situation--must I stop the show while I relamp it?

Loads do not have to be equal and can be operated independent of each other. In the DD mode, each half of the SSR is fired appropriately to the channel assigned as compared to the standard mode where both halves of the SSR are fired at the same phase angle after ZVC. The result is that the lamps are actually running DC* as compared to AC. The positive switches are operating as one channel and the negative switches are operating as the second channel. In 60cps AC, there are 120 ZVCs followed by 120 ramps. With DD, 60 are directed to one fixture, and 60 to the other. That is why the lamps are 77 volt as well. The peak voltage (absolute with reference to neutral) remains the same, but with 1/2 of the waveform missing, the RMS becomes lower.

If we pictured this circuit using back to back SCRs, one SCR would be handling one channel, and the other would be handling the other. That is why I say that fully loading a 2k dimmer with the full 2k on channel "A" would be bad. Usually, both SCRs would have the work divided, but in this mode, one SCR is doing all the work while the other is doing nothing. Again, remembering that at its heart, a SSR contains 2 SCRs and an opto-coupler. Again, the dimmer is built so conservative, that probably no harm would come of it.

* = Pulsed DC to be exact, so the arcing associated with DC does not occur.

[JD]

Whatever the case is even if you get 24 DD you will still only have 12 control channels there as you are splitting the incoming channels.

Actually, you will get 24 channels of control on the 12 dimmers. There is a software change that is made on the dimmer so that it understands this.

[KeeperoftheKeys]

I thought he had 6 incoming dimmer channels so that would give him 12 channels....

[MNicolai]

Yes, numbers are being confused. You have only 6 circuits on your FOH catwalk, and therefore will only be able to double to get a total of 12. Beyond that your easiest solution would lie in running DMX data cable up there and operating satellite packs.

[marcusianl]

DMX sounds like it might be the best option, seeing as I'm already in a position to run DMX line to our catwalk for the color scanner we're hopefully getting (see New Equipment Thread). If I were already running DMX lines, how many lines would I need to double my controlled channels in the catwalk from 6 to 12 and what type of satellite packs do you recommend for StagePin connectors? Also, how difficult would it be to control satellite packs using an ETC Express? Do they patch in like normal dimmers?

[shiben]

You will need to run 1 DMX line to the dimmers and then 1 for your Scroller device, seeing as they have different ends (the dimmers will have female connectors, i believe, and the scroller is a male connector), either with 3 or 5 conductors, depending on what they use. Assuming your new dimmer pack would operate like ours does, there will be a male and female DMX plug on the pack itself, and you can daisy chain them. I would imagine that they would patch like normal units, although I dont have experience with your particular control system.

Do you have any Constant circuits on the catwalk? If you do, you can avoid having to buy Non-Dim or Constant dimming modules for your rack... Our FOH and both over stage bridges have Constant circuits, each one a 20A circuit, every 10' or so, and if you have a similar situation you can have even more channels available. If thats the case, you can get one of these:

Lighting solutions for Theatre, Film & Television Studios and Architectural spaces : ETC

In fact, you could probably use some of the 2x10A ones with the other posted solution, to keep your rig all ETC. However, I would expect that these cost a lot more than the other options.

[marcusianl]

We do not have any constant circuits, all our plugs are dimmered. I don't have a problem with running two DMX lines to the catwalk. The way our space is I don't think it would be too difficult. If I can chain them together, will they still be able to be patched as individual units off the single DMX line?

[KeeperoftheKeys]

Unless you have multiple DMX universes or a fear that the single cable you are running to the catwalk will be damaged in some way and therefor need a backup you only need to run one DMX cable.

It would be good practise to then put an opto-isolated splitter on the catwalk and have seperate DMX runs for the local dimmers and the "intelligent" lights. Note though that if you intend to buy fixtures that support RDM and want to use that functionality the splitter also needs to support it.

Other than that if you are permanently installing this DMX line you could ask the IT dept to permanently install a CAT5e/6/7 cable...

[JChenault]

You will need to run 1 DMX line to the dimmers and then 1 for your Scroller device, seeing as they have different ends (the dimmers will have female connectors, i believe, and the scroller is a male connector),

I don't believe this is correct. In my experience the genders are compatible. IE the 'emitter' of the signal is always a female. The 'receiver' is always a male. (I did see an ETC architectural unit which violated this - but it is not the usual case).

This means that you can run the cables however they make sense to you. There are two DMX outputs on the back of the express. You could run one of these to your FOH catwalk, and then daisy chain all of your new dimmers, scrollers, etc on that cable ( up to 32 devices per cable) - OR - you could run a cable from the last dimmer rack up to the FOH catwalk (Again assuming you do not put more than 32 devices per cable). ( This assumes you do not need more than one universe of addresses which, based on your post, I don't think you need).

Be sure to terminate the end of the DMX cable. As it gets long, you increase the possibility of reflection issues.

You could also get a splitter to turn one DMX cable into several. This is probably overkill in your space at this time. They are moderately spendy and require power to operate.


As for addressing - you will have to decide what DMX addresses you want to map your existing dimmers, your new dimmers, and your scrollers to. When you patch your show, you will assign these dimmer numbers to whatever channel you wish on your console.

[JChenault]

Unless you have multiple DMX universes or a fear that the single cable you are running to the catwalk will be damaged in some way and therefor need a backup you only need to run one DMX cable.

It would be good practise to then put an opto-isolated splitter on the catwalk and have seperate DMX runs for the local dimmers and the "intelligent" lights. Note though that if you intend to buy fixtures that support RDM and want to use that functionality the splitter also needs to support it.

I'm curious. Why are you recommending a splitter in this configuration? Is it just to protect from damaged cable, or is there some other reason I am missing.

(And should I consider a splitter in my venue )

[MNicolai]

CC20's shouldn't be too expensive. It's a glorified circuit breaker dressed up in an air flow module. Just get three CC20's and replace the dimmer modules you have with those. Then you will have six 20A circuits on your catwalk which you can put probably one or two satellite packs on each depending on their current ratings. You'll probably only be able to find them in 5-15's and pin connectors, so you may need to replace the connectors on your fixtures to accommodate.

With this info goes the usual disclaimer that unless you have a devout understanding of electricity, you should not undertake rewiring everything on your own. It's in your best interest to consult a qualified individual. Even if you do feel competent, it's a liability for the school to allow you as a student to rewire devices without proper training and/or supervision.

[KeeperoftheKeys]

I'm curious. Why are you recommending a splitter in this configuration? Is it just to protect from damaged cable, or is there some other reason I am missing.

(And should I consider a splitter in my venue )

It has always been my understanding that it is "best practice" to keep different types of devices on separated DMX lines, or at least to separate movers/intelligent stuff from dimmers.
This is to prevent that a faulty device polluting the DMX signal will affect everything (and to prevent shorts from immediately blowing everything if you have an opto-isolated splitter etc.).

(I believe Adam Bennette's Recommended Practice for DMX512 also mentions this but I don't have it near to me to verify that at the moment)

[MNicolai]

It has always been my understanding that it is "best practice" to keep different types of devices on separated DMX lines, or at least to separate movers/intelligent stuff from dimmers.
This is to prevent that a faulty device polluting the DMX signal will affect everything (and to prevent shorts from immediately blowing everything if you have an opto-isolated splitter etc.).

(I believe Adam Bennette's Recommended Practice for DMX512 also mentions this but I don't have it near to me to verify that at the moment)

It's also a good practice to make sure if something spikes the voltage in the DMX lines that the console doesn't become damaged in any regards.

[SteveB]

CC20's shouldn't be too expensive. It's a glorified circuit breaker dressed up in an air flow module. Just get three CC20's and replace the dimmer modules you have with those. Then you will have six 20A circuits on your catwalk which you can put probably one or two satellite packs on each depending on their current ratings. You'll probably only be able to find them in 5-15's and pin connectors, so you may need to replace the connectors on your fixtures to accommodate.

My post from yesterday lists the website for the Lex Products Anaconda 6x800w dimmer packs, that do indeed have 2P&G receptacles and that would be my choice for this application.

Steve B.

[JD]

During the renovation at our school's theatre this past year we received a new Sensor+ Dimmer rack. However, when wiring our FOH catwalk, they didn't run new Dimmer lines, they just ran new cable through the existing ones, so we only have 6 Dimmers on our catwalk (although we have 18 instruments and 24 outlets). Is there any way to increase the number of controllable dimmers without running more cable? I saw something on ETC's website about a Dimmer Splitter. Would that do the job?

-Marcus

Ummm.. Something we may have all overlooked: If there were 24 outlets up there before the renovation, is it possible that they are already home run to the dimmers? It could be that when the system was upgraded someone was a bit short sighted and tied separate lines together at the rack and only allocated 6 dimmers to the catwalk. If this was the case, reassignment would be easy.

[MNicolai]

Very unlikely as it sounds like the previous usage didn't warrant 24 home runs, though possible.


Sent from my iPhone using Tapatalk

[marcusianl]

Well the work order supposedly requested all our circuits to be put on individual dimmers (according to my teacher) and the electricians apparantely got lazy or something, and it was already too late to complain when we figured this out. There were 24 circuits up in the catwalk before the renovation, but I didn't have an opportunity to work with the system before the renovation so I don't know if they were each individually controllable. How would I find out if each of the circuits is home run or not?

And as for the CC20's, if I already have stagepin connectors on my instruments and the packs that SteveB recommended have stagepin outlets, wouldn't I just have to swap out the dimmer units on the rack (which I was shown how to do when ETC did their "training session") and attach the dimmer packs to the connectors up in the catwalk? Or do I still need to run DMX cable for control?