DMX Cable Length

[TalJ]

Hi,

I am planning to run a cable from my theater booth, to the actual fixtures which are about 35 meters away. I notice that most cables are sold around 10 meters at the maximum, however some come in cable wheels of up to 50 meters. Are there any signal weakening issues out there?

Thanks in advance,

TalJ

[kikabyte]

In theory you can run DMX lines upto 1000 meters with 120 ohm good quality cable, but to stay safe, keep it under 400 meters. And limit your fixtures to a maximum of 32 (i think)..

[remco_k]

And *DONT* forget to terminate the end with a 120 Ohm terminator. Otherwise you are asking for big troubles.

[TalJ]

Thanks for the responses!
If my last fixture does not have an output (a very large DMX dimmer...it's ancient), so i'm guessing I don't need a terminator?
Thanks,
TalJ

[Tom]

PLEASE use proper DMX cable instead of mic cable otherwise you will have issues.

I would also recommend using 5 pin.

Something else worth noting!!! VERY IMPORTANT!!! You can use CAT5 cable for running DMX down and this is usually recommended for installation use. Just to let you know.....

[remco_k]

I would also recommend using 5 pin.

For what? When all devices have a 3 pin connector, like they have here, there are about 0 reasons to use 5 pin xlr.
In fact there then is at least 1 reason NOT to use 5 pin XLR: more connectors give more potential problems.

Apart from that, a 5 pin XLR is cabled so that pins 4 and 5 are left unused. PIN 1,2 and 3 are used the same as in 3 Pin XLR connectors.
So there is no theoretical nor fysical reason to choose 5 pin xlr above 3 pin xlr.

But, if all fixtures have a 5 pin connector, its better to use 5 pin xlr ofcourse, just to minimize the number of connectors flying around.

[THW Mark]

PLEASE use proper DMX cable instead of mic cable otherwise you will have issues.
I would also recommend using 5 pin.

i doubt 5-pin is better then 3 pin. There are a lot of fixtures, that feature a 5-pin input, but have two of the wires not connected: data2 is not used then. (in best case scenario only linked to the 5-pin out.

i'd agree line cables are better (common mistake for long distances). The terminators are used to prevent 'echo' over the cable, but with a descent line cable, it shouldn't be necessary.

[Tom]

From mine experience and that of people I know who have been in this business a long time, 3 pin is only used on cheaper DMX gear. 5 pin is the proper DMX connector which should be used. 5 pin is the ONLY RIGHT CABLE according to DMX standards. 3 pin is non-compliant - http://www.blue-room.org.uk/index.php?s ... t&p=265275 - see here if you don't believe it!

This is also why all lighting desks have 5 pin XLR out and not 3 - it's the correct one to use for DMX!

[remco_k]

From mine experience and that of people I know who have been in this business a long time, 3 pin is only used on cheaper DMX gear. 5 pin is the proper DMX connector which should be used. 5 pin is the ONLY RIGHT CABLE according to DMX standards. 3 pin is non-compliant - http://www.blue-room.org.uk/index.php?s ... t&p=265275 - see here if you don't believe it!

This is also why all lighting desks have 5 pin XLR out and not 3 - it's the correct one to use for DMX!

We know that, the DMX512-A protocol tells that a 5 pin XLR should be used and nothing else.
In the original DMX512 standard this rule did'nt exist and many manufacturers (and so did Martin, for instance, wich is not quite a cheap manufacturer) created many fixtures with 3 pin XLR's on it.
BUT: thats not what we are talking about here.
We are talking about if a 5 PIN is better or not than a 3 PIN XLR.
There is no fysical difference other than that it has 2 pins extra, who are not connected to anything. They are there for nothing.

The DMX512-A also explains why they have chosen the 5 PIN:

a 3-pin XLR can easily be connected to a sound board. If an electronic piece of equipment was accidentally connected to a sound board with phantom power on, the 48 volts of phantom power sent along the cable would probably damage the circuitry inside the light, necessitating the expensive repair or replacement of the light.

So, it has only be done for 'stupid' people thinking that they can control their DMX fixtures with the 48V fantom power button on their mixing desk.
On the other hand the 5 PIN XLR has quite the same problems:

some companies used the extra pins (4 and 5) to carry (usually 24 VDC) power anyway, which would again destroy any equipment which used those pins to carry data. For these reasons, DMX512-A forbids using the extra pins to send power or any other use that does not comply with EIA-485 signal levels.

Source: http://en.wikipedia.org/wiki/DMX512-A
Reading the above can only go down to one solution: a 5 PIN XLR is the standard, but not typical better than 3 PIN's. It just makes no differences other than that the connectors doesn't fit in eachother.

[Tom]

I also know of some Robe fixtures which use 3 pin - but again these and the scanners are at the low end of the price scale as far as movers are concerned - the expensive ones use cat 5 and 5 pin.

Also, you would be better IMO using 5 pin as much as possible and then having an adapter on the end. This is the way I do things even if the fixtures have 3 pin. I read somewhere that it is possible in the near future 4 and 5 are going to be used for something - can't remember what for or where I read it off the top of my head though.

So as these are new leads being made up now, why not use 5 pin to conform to the new standards?

Using 5 pin will also stop the cables getting borrowed or stolen by soundies.

Personally I would use 5 pin - just don't use 4 pin whatever you do! 4 pin XLR cables are used for carrying power to devices...

[LJ_krede.dk]

I read somewhere that it is possible in the near future 4 and 5 are going to be used for something - can't remember what for or where I read it off the top of my head though.

I have from a book, that the two extra connections are used (or should have been used) for the lights sending data back to the dmx-desk, like status message for every light about the lamp and so on, and for automatic adressing. Dont think it ever have been used,

So as these are new leads being made up now, why not use 5 pin to conform to the new standards?

for a few month ago i talk to an engineer from Martin who told me that at some time they will switch to rj-45 which is like network cables.

[Tom]

I have from a book, that the two extra connections are used (or should have been used) for the lights sending data back to the dmx-desk, like status message for every light about the lamp and so on, and for automatic adressing. Dont think it ever have been used,

That would be RDM - Remote Device Management - for some reason I thought that was on RJ45!

for a few month ago i talk to an engineer from Martin who told me that at some time they will switch to rj-45 which is like network cables.

Many fixtures already have these as do many lighting desks. For example, the ETC Express has an RJ45 for 'ETC Net'. 'Artnet' is also over RJ45.

Fixtures which already have these RJ45 connections on are, for example, the Robe 700E's.

[THW Mark]

From mine experience and that of people I know who have been in this business a long time, 3 pin is only used on cheaper DMX gear. 5 pin is the proper DMX connector which should be used. 5 pin is the ONLY RIGHT CABLE according to DMX standards. 3 pin is non-compliant - http://www.blue-room.org.uk/index.php?s ... t&p=265275 - see here if you don't believe it!

This is also why all lighting desks have 5 pin XLR out and not 3 - it's the correct one to use for DMX!

actually the main reason why 5-pin should be used, is that it is much easier to separate lighting cables from microphone cables. You can't accidently mix them up and blow up a lighttable with your phantom powered mic cable or something. The 2 extra wires in the 5-pin are most of the time not used.. (see also the wikipedia article on this: http://en.wikipedia.org/wiki/DMX512A)

[remco_k]

Thats exactly what I told a few posts earlier...

[THW Mark]

Thats exactly what I told a few posts earlier...

sorry, didn't see the second page

[djSupport]

Tom arent you like 16 so these guys are a little more educated?? I'd go for 3 pin too it looks nicer! Buy the way which ever way you swing pick up my 3 pin or 5 pin XLR T-shirts designed by me!!! http://djsupportgifts.spreadshirt.net/e ... ifts-45577

[Tom]

Maybe they are - depends how long they've been doing it. I'm going on personal experience which I have a lot of (I work in theatre too and have been doing it a long time) and from what others have told me who have been in the industry many many years, and some of which own their own lighting companies.

Anyway - CAT5 cable is the way to go in an installation.

And I'm still saying use 5 pin instead of 3 pin! Even if the fixtures do have 3 pin, it will save the cables getting mixed up with soundy ones, also if you purchase any fixtures in the future which use 5 pin then it's already there.

[remco_k]

So I say (again);
All fixtures that I buy here in Europe (Netherlands) have 3 pin XLR's.
So if I take on your advise (which I don't) I should use a 5 to 3 and 3 to 5 pin converter at every fixture.
Now thats asking for troubles!
You are telling me that's better? Come on, you gotta be kidding!
I think (<- see that, I'm not sure) that world wide the most fixtures are 3 pin XLR, and even think that they stay that way until a compleet other form (think RJ45) is coming up.

I have just 1 device with a 5 pin XLR, thats my USB to DMX interface. So I use only one converter there to 3 pin XLR and from there its simple. I'm not gonna change that, and I guess that nobody would do that. Using so many converters in the DMX universe, is not a good idea.
Edit: Seems I'm not the only one in the world: http://thedmxwiki.com/definitions/dmx_cables

And stays that a 5 pin XLR has no technical benefit above 3 pin XLR.
I see more benefit by staying at the 3 pin XLR.

About the CAT5 cable (I'd use CAT6), I agree with you.
Especially because I think RJ45 sockets and some kind of ethernet protocol will be the next after DMX.

[Mattotone]

The only thing i can add to this topic is
I agree with the 3 pin, the cost of adapters will add up quickly.
However Any patch panel, or cable coming from the rig should be five pin. It stops people plugging anything else into it.
Microphones (it has been done, Makes the microphone click to the dmx refresh rate.) Or Mixers.
It also allows visiting / replacement lighting desks to be plugged in as most is 5 pin.

My Lighting is 3pin, i changed one channel on my snake to five pin and use just one adapter.
It stops mics, DI's etc being mistakenly patched into the dmx channel on the snake.

My DMX cables are also labeled as DMX, so to avoid "Some" confusion with the Mic Cables.

[remco_k]

Yeah, when using snakes I can imagine that the chance on mistakes is way bigger. I would have done the same when I was in your situation. It just rules out really big problems to. (like plugging into a mixer mic channel wich has 48V phantom power enabled).

I only work with mobile DMX installations. Every time a completely different setup, taking hours to build, then hours to program.
There is just one point I go from 5 to 3 pin xlr, thats about 10 cm away from my USB to DMX interface. From there everything is 3 pin XLR.Then most of the time a few meters DMX cable, then a DMX splitter, one output goes to the rig hanging at the ceiling, one other goes to the fixtures standing on the DJ booth and/or hanging behind it.

Mixing up with the audio boys is most of the time no issue, as I most of the time build and cable the DJ equipment on the booth, connect the amps and speakers, while they are hanging up and cabling my lights.
You now might wonder why I don't do that myself; I have a bad back. I can't lift anything a little heavy without getting killing pain from it. Especailly lifting above my head is a big problem.

[Tom]

So I say (again);
All fixtures that I buy here in Europe (Netherlands) have 3 pin XLR's.
So if I take on your advise (which I don't) I should use a 5 to 3 and 3 to 5 pin converter at every fixture.
Now thats asking for troubles!
You are telling me that's better? Come on, you gotta be kidding!

This is not what I said/meant. Run 5 pin from the interface down to the first fixture and then stick an adapter on the end. Then chain all the fixture with 3 pin.

I think (<- see that, I'm not sure) that world wide the most fixtures are 3 pin XLR, and even think that they stay that way until a compleet other form (think RJ45) is coming up.

I would say most fixtures in the world are 5 pin.

It will be a long time before RJ45 completely takes over, if ever.

[Tom]

Out of interest Onge, which fixtures are you exposed to on a regular basis?

Doing lots of theatre work I get exposed to lots of Martin and Robe gear, such as Mac 600's, 500's, Robe 700's all sorts and all these use 5 pin. In my theatre experience, the only stuff which uses 3 pin I've come across are the High End Trackspot and the Robe 170's. Both of which are budget disco aimed gear rather than serious theatre use.

[LJ_krede.dk]

Out of interest Onge, which fixtures are you exposed to on a regular basis?

Doing lots of theatre work I get exposed to lots of Martin and Robe gear, such as Mac 600's, 500's, Robe 700's all sorts and all these use 5 pin.

to my knowlege, the mac 600 are using 3-pin only:

http://martin.com/service/downloadfile. ... PDF&cat=65

http://martin.com/service/downloadfile. ... PDF&cat=65

or is there other mac 600's with 5 pin?

the other Moving heads from martin have both 3 and 5 pin but the mac 3, its only have 5 pin

http://martin.com/productgroup/productg ... selgroup=0

[remco_k]

I work a lot with Robe movingheads, all having 3-pin.
Like Onge, I have never seen fixtures with 5-pin XLR's on it.
Only one fixture comes to my mind, who might have 3-pin and 5-pin XLR. The Martin Atomic 3000. Though I'm not sure. If I'm wrong, it only has a 3 pin.

Also it might be possible that companies that rent out those equipment might replace all connectors to 3 pin. Or to 5...
Just for their own 'compatibility'. And since I only rent...

[Tom]

I work a lot with Robe movingheads, all having 3-pin.
Like Onge, I have never seen fixtures with 5-pin XLR's on it.
Only one fixture comes to my mind, who might have 3-pin and 5-pin XLR. The Martin Atomic 3000. Though I'm not sure. If I'm wrong, it only has a 3 pin.

Also it might be possible that companies that rent out those equipment might replace all connectors to 3 pin. Or to 5...
Just for their own 'compatibility'. And since I only rent...

Out of curiosity what LX work do you do? Is it DJ stuff? If it is then I can see why you would only come across 3 pin. Like i've said - the robe 700's are on 5 pin as are all high end fixtures.

EDIT: Can't read! It's worth noting that the mac 600's are quite an old fixture now in comparison...