DMX Lighting Question

[Mike Sinclair]

Sorry to post this here guys, but I tried googling and can't find what I'm looking for. I have never used a DMX controller (always used copilot by american dj, well Elation, nowadays) anyway, I'm looking to get into either ADJ myDMX or Chauvet's Show Xpress. I haven't decided which (your input appreciated, but that's not my question). My question: I understand that when you use DMX lights, you daisy chain the dmx connectors and you also daisy chain the power cords. I was under the impression that all dmx lights have a power in and out. Well, I have an American DJ Galaxian Laser light that does not have a power plug-in... just the "out". It has dmx in and out though. So, would I have to run that light to it's own outlet and not include it in the "chain"? Seems strange they left out a power "in" on that.

[Darryl]

I'm guessing it only has power in, rather than just power out. Otherwise how would it work. None of my lights have the daisy chain power connectors. I use multi-socket extension cables.

[krzyd]

Sorry to post this here guys, but I tried googling and can't find what I'm looking for. I have never used a DMX controller (always used copilot by american dj, well Elation, nowadays) anyway, I'm looking to get into either ADJ myDMX or Chauvet's Show Xpress. I haven't decided which (your input appreciated, but that's not my question). My question: I understand that when you use DMX lights, you daisy chain the dmx connectors and you also daisy chain the power cords. I was under the impression that all dmx lights have a power in and out. Well, I have an American DJ Galaxian Laser light that does not have a power plug-in... just the "out". It has dmx in and out though. So, would I have to run that light to it's own outlet and not include it in the "chain"? Seems strange they left out a power "in" on that.

I've never seen primary power in and out on DMX lighting, most of my fixtures are Chauvet, there is a heavy learning curve for showexpress but I manage.

[Mike Sinclair]

Darryl, I guess I got it backwards. It has a place to plug the power cord into the light fixture, but not an "outlet" to put another light into it. All of my other lights have both. Multiple outlet extension cords defeats the purpose for me. I used to plug all my lights into cords way back when. That's why I bought the Co-Pilot... to clean up a lot of clutter... hmmmmm... I'll have to look into this more.

[DJMartin]

Hi Mike
It doesn't matter from where the fixtures get the power supplied. Rarely you find fixtures with both, power in and out to daisy chain, but this is just for the ease of usage, no technical requirement. You can use a power rail on top of your stand (or truss) to feed the mounted fixtures.

In the DMX area, you noticed right, fixtures are always daisy chained. And do not forget to terminate them at the end of the line. Termination can be done in two ways. Very common is to have an XLR connecter with the built in 120ohm resistor and then you connect that 'empty' connector at the last output. Some fixtures offer a dip switch to terminate, there you don't need the connector mentioned before.

Some people are using DMX Splitter to reduce to the need to cable multiple stands daisy chained. As the word says, the splitter split the signal to 1-n independent DMX lines. Logically they are all the same universe (same DMX address range), but you can cable each stand with a direct cable and need to terminate each such line.

You get quite cheap DMX controller for traditional lights (dimmer light, par cans). For intelligent lights, a good desk is pretty expensive. Software solutions are quite common these days. Personally I do use Nicolaudie Sunlite Suite 2 with a USB DMX dongle. They do OEM versions. One is known as DASLIGHT. Then I saw freestyler mentioned elswhere, but I do not have experience on that.

Hope I removed your clear vision about DMX... 

Martin

[DJMartin]

Mike, forgot to mention that some of the available dmx software do support MIDI consoles like the Behringer BCF2000 or Novation Launchpad or Akai APC20 and other good products. They do help to trigger new scenes or cues, fading colors, dimming lights.

[discodonal.com]

I use ADJ MYDMX and only certain fixtures can daisy chain power such as mega par profiles uplighters. I have 2 x moves, revo 4 and several mega par profiles all on dmx with mydmx and works great.

[melchz]

 a lot of the LED fixtures have daisy chain power but can only do a few fixtures.  my led cans can handle about 8 fixtures daisy chained power wise.  I've been looking at some led bars that can do 20 or so.  I haven't seen too many other fixtures that have that feature on them.

[Darryl]

You have to remember that the plug/socket you are starting the chain from and the cable to the first fixture had to carry the combined current of all of the fixtures before it. If you are plugged into a fused outlet (uk plugs incorporate a fuse I don't know about other countries) you could blow a fusr with too many chained. Worst case is you could start a fire from a wire getting hot.

[Darryl]

(clarification: you need quite a log of lights to get into this situation. Check the specs for your fixtures. It will tell you either in amps or kilowatts how much power it consumes. You can pretty much just add them up to get an idea of the total. In reality it fluctuates depending on what the fixture is doing, but thd manyfacturer will err on the side of caution and list thd maximum it will draw.)

[DJMartin]

Full support on Darryl posts.

In the Par64 world the calculation was pretty easy. 1kW each lamp straight. Here in Europe 1kW divided by 240V equals 4.17 Ampere. So in a 10A fused socket, max 2 Pars would fit or it will blow the fuse after some time (depending about type of fuse).

With the LED it is a little different. E.g our Eurolite SLS 7x3W RGBs (TCL LED). 7x3W equals to 21W, but the manual says 50W, more than double. Do your calculations with the values specified in the manual, then you are on the safe side.

[Mike Sinclair]

Thanks for the input guys. I will do some more research. I just stumbled across Luminair for iPad or iPhone. Has anyone here tried it? Looks interesting...

[Nicolee]

(clarification: you need quite a log of lights to get into this situation. Check the specs for your fixtures. It will tell you either in amps or kilowatts how much power it consumes. You can pretty much just add them up to get an idea of the total. In reality it fluctuates depending on what the fixture is doing, but thd manyfacturer will err on the side of caution and list thd maximum it will draw.)

Although agreed you do have to have plenty of lights to cause a cable to overheat, however there are other reasons;

Using an extension reel that is not fully unwound.
Using a cable within the chain with a hot or open neutral, this is almost certain with nastiest of fires.
Using a cable of differing specification, i.e. mixing 0.5mm 1mm, 1.5mm within the chain. The lowest spec cable won't be able to take the load of appliances following it.

A hot neutral can cause a fire even with one appliance, with many the speed of the overheating will only speed up.

Hence the need for PAT testing.

So a few pointers;

Fully unwind all extension reels.
Check any cables which can be opened up and all terminals are tight especially the neutral terminals. I tend to use thread lock on the terminal screws so they don't work loose in transit.
As a minimum only use 1.5mm 3 core flex which in the UK will take a load of 16amps, this way the fuse will blow in an overload situation.
Inspect flex of each appliance or cable once per month for twisting, damaged outer sheath or plug/socket. Repair plug/socket where possible, discard twisted or damaged cables.
Down rate fuses to correct spec where possible to prevent overloading.
PAT test all equipment and cables once yearly.

Beware as this is your reputation and safety of your clients here, I know of one DJ in the Midlands who managed to almost burn a social club down because of his poor maintenance of his equipment.

[DJMartin]

Fully support Nicolee's recommendations on cable handling. That do apply in general to all your household, your office/workplace or any other place where electricity is used. I'd like to add few points to that.

Using thread lock is one thing. Never ever put a blank flex cable in the terminals and screw them down. A flex cable consists of tiny thin copper wires and the screw might cut them apart... result is a reduced diameter, so it's getting hot in there until the fire start. Always use wire sleeves (http://commons.wikimedia.org/wiki/File:Trailerable_wire_sleeves.JPG?uselang=en), they are criped to the blank cable and prevent from cutting the wires appart. They are available in a wide size starting around 0.25mm2 - 16mm2 or above. There are with plastic cover or without.

Respecting this fact, stay away on using preconfected cables from the supermarket next to you. You never know how good the connection between the cable an terminal is since it is surrounded with the pressed plastic you cannot open. Here it's pretty common to sell them with 0.75mm2 or 1mm2 cable. That might be fine to connect your bedside lamp, but not for heavy load. I recommend to always go with 1.5mm2 cable for 10A (in some countries 16A are allowed), connect the sockets on your own using wire sleeves. Choose connectors that can be opened again, might be easier and cheaper to control the cables regularly.

Be also cautious when using power rails. the cable aspects are like above, the terminals in the power rail cannot be checked since you can't open them anymore. Some glued or they used these one-way screws. I opened some of them and I'm sometimes scared what I do see.

If one is not into the electricity business, then better go to the electrician of trust and get support from him. You might pay a little more, but that's nothing compared to having a fire. I do know that, my entire stock burned down in 2011 because of an fire starting in another companies shop next to mine. Unfortunatly the fire got into the whole building. Have you ever seen melted truss segements?

Take care and be safe
Martin

[Mike Sinclair]

Is anyone using ADJ myDMX on same laptop as ots? If so, is it a pain to switch back & forth?