Hi. I'm having issues with my school's lighting system in our "theatre". I am new to the school here in Viet Nam and no one here has a clue how to use this lighting system. It is a 20 LED par can light system, 3 pin DMX throughout, a board that looks like a Chauvet Obey 40 but seems to be some kind of no-name DMX 512 desk. The lights look to have been daisy chained. In the past, they have been used as just a plain red wash or green wash or flashing mode. It was working ok but the stage looked like hell. I WANT to be able to control them individually. They were all initially set up with their dip switches set for 1 and 10 only.
I have tried setting them to separate channels (i.e. changing the dip switches to 1 then 1,5 etc.) but once I did that, they started randomly flashing. I tried switching them back to 1,10 but they are still doing their own thing. I tried setting them all to the proper address with 10 switched on too. Still no response. Now, I can't even get them back to going all red.
I'm fairly new to DMX systems. Can anyone offer suggestions as to what the heck I have done wrong?
I also have a couple of other questions.
Since I have 20 par cans but only 12 fixture buttons, can I assign 2 lights to one address?
Could the polarity switch on the back of the board do this?
Help, please, anybody.
hi there - so DMX is just a signal of numbers sent to the lights, the string of data looks like channel 1 data, channel 2 data ect upto 512. The controller sends out all of this. If two devices use the same addresses they simply listen to that channel data. You can have all of them or non of them set to address 1 and and it will work.
With your equipment i would recommend pairing the lights up and using one address for each pair. The LED fixtures will use maybe 3 or 4 channels or addresses of data, so start with channel 1, the next would be channel 4(or 5) ect. Some desks can be patched so that you can control them in different ways so take a picture of your desk and upload it for us all to have a look.
It sounds like you have an error in your DMX wiring or a LED can is kicking out DMX aswell so maybe test one fixture then plug in the next ect untill it breaks, then you have found where the break is. There is a device limit per DMX bus of 32 devices including transmitter and the bus should be properly terminated using a terminator (120ohm resistor over pins 2 and 3). The length of all the cables together shouldn't really be longer than say 1000m using the correct cable... usually in practice other cables are used such as cat 6 or audio cable which can degrade the serial signal.
The polaraty switch could do that - and wont damage anything if you swap it over. It'll just either work or not work, the working way is the correct way.
Would be good to see a pic of the desk in question and to know the model and make of your LED can's to help you some more.
Hi Matt, Thanks so much for responding so quickly! I will take some pix on Monday when I am back in the theatre and post them. I am also going to start Monday with fixture 1 and see if I can get it to listen up. Isolating 1 will make the process easier I hope. I will also check for a terminator and see what kind of cables these cheap bastards used too. It would make sense that they tried to shortcut to save money...
Most recent update: I tried to start with light #1. Tried to connect only it to the board. I could get it to turn on, but then it changed colours three seconds later and then turned itself off. WTF? I don't have a termination plug handy but I was HOPING that it wouldn't matter so much with just one light... Maybe I wrong...
Have you made sure the dip switches on the fixture are set to DMX address 1 and DMX enabled. There's usually either a switch at the start/end that tells the fixture to listen to DMX signals or to do it's own preset modes.
You need to first find out what each DIP is doing, and that can be a real pain with "No name" kit. Without sorting that out you are not going to get anywhere.
Mic cable can cause problems, but doesn't normally. Termination too is correct, but not always necessary. CAT5 is fine, but should only be used for the installed part of any cabling. It breaks too easily to use as flex.
Pairing will be fine, or you could say run all the back light as one address leaving more channels free for front light.
Let me begin by saying that there is no manual for these lights or for the board. Someone in their wisdom disposed of it before I came along. I have scoured the internet looking for similar lights/board and experimenting with the ones I have. Today I discovered that without DMX hooked up, dip 1=red, 2=green 3=blue, low intensity. My next 'experiment' was to start with fixture 1 and see if the board would talk to it in manual DMX mode. See above for results. Frustrating. When I had fixture 11 on red all the subsequent fixtures with dips 1 & 10 on went red just the same. Seemed like something was working ok. But as for listening to the board, nada. Like I mentioned, I could get light one to turn ON (all LEDS so white-ish) with the board, but then a few seconds later, it changed to red/green and then just quit. If I put the slider back to 0 then up full again, it would do the exact same thing. I am considering calling a priest for an exorcism. I have never seen lights do such erratic <poop>.
If you connect one fixture to the desk, set the dip switches 1 to on and all the others to off, that might set it to DMX address 1 (based on manuals for other cheap LED par cans). Then on the desk if you put up various faders do you get any light?
They're probably use 5 or 6 channels, red, green, blue, shutter, intensity or something like that, so you might need to put channel 5 on, along with channel 1 to get red if you follow?
Thanks to all who have replied thus far. I have connected one light to the board. I have done a soft reset on the board, I think, as I got all LEDs to blink thrice. I have set the one light with dip 1 only, dip 10 only, dip 1 and 10 only (3 tries). The only response I can get is that the light turns on, then 3 seconds later changes (by itself) to red/green, then a few seconds later turns itself off, with no changes from the board. I have no terminator plug so I can't test it with a terminator plug in. When I unhook it from the DMX cable, I can set it to solid red/green/blue. I am beginning to think it is the cable...? Or the lack of a termination plug...? Could it be a software problem?
p.s. I originally set all the dips for specific channels. I have done that before. Everything went haywire when I tried it, so I went back to the very beginning.
ok - the controller is a generic one - i have two of those in my hire stock - they're not great but they're ideal for smaller stuff. here's a run down of how they can be used (one of many ways)
the fixture buttons on the left are 16 channels apart. there's 12 of them so 192 channels on the desk that can be used. the first one starts at channel 1 the next at channel 17 ect. as far as i know you can't change the channels on the desk so you'll have to set your led's to the channels 1, 17 ect. then you select the fixtures 1-12 and the faders control them. the faders are 1-8 and then there is a page select to get to the 9 to 16. It's a bit crap to op a show on. I suspect that you'll be able to do just use the first page tho on the 12 fixtures. you can program scene chases and other things on the desk but i dont really ever use it... Transcension DMX Operator Mk 2 - DMX Master - Djkit.com is another model - and there are others so finding a manual for one shouldn't be too difficult. if the buttons look the same on another then it's probably the same cheap generic desk.
as for the led's i think you'll have to work out how to patch thoes onto dmx as others have said - sounds like there in a generic stand alone mode.
My biggest problem is that no matter what dip switch settings I use, the light is failing to respond. Or if it does, it responds and then without any change on the board, it changes and then shuts itself off.
I started out with one light, with dip switch 1 on. Then with 1 and 10 on. Then with just 10 on. Those three settings seem to be the most standard settings to trigger DMX mode. It was only when 1 and 10 were both on that the light would go on to full brightness for all colours, then change to red/green/ and then go off, all while the fader 1 was at full...
I'm really trying to troubleshoot here...
I'd be surprised if it was lack of termination that was the problem, do the lights respond to sound (tap the light and see if anything happens)? It occurs to me that they might be in some sort of disco sound to light mode and that's why they're behaving erratically.