Blaize110 Posted December 5, 2009 Share Posted December 5, 2009 Just been getting in the spirit of christmas and setting up a load of DMX fixtures in my room. After remedying the SoundLab dimmer problem by swapping DMX + and DMX -, it is now working fine. However when I plugged the chain together (1 x Dual Moonflower, 4 x LED "PAR" 36es, 1 x Soundlab dimmer, 1 x Terminator), one of the 36es started flashing wildly, no matter where it was on the chain or what address, another would flicker occasionally. Eventually I removed the terminator from the last in the chain (Soundlab dimmer) and the flickering stopped (the SoundLab dimmer had been working fine in both setups). I checked the terminator and it is definitely a 120ohm resistor and across pins 2 and 3. I am happy that it all works now, however it is puzzling that the terminator was introducing interference. I am pretty certain that none of the fixtures are terminating themselves as they all have DMX outs. What do people think? Link to comment Share on other sites More sharing options...
JimWebber Posted December 5, 2009 Share Posted December 5, 2009 I would suggest checking your cables and connections. If a DMX Leg goes open circuit, or High Resistance, without a terminator the system may still work. Once a Terminator is added, this can show up the fault. - It is all due to the differential signalling involved in DMX / RS Ummm something or other - I cannot think off the top of my head - is it RS 485?????? There are a few explanations on here, a search may bring them up. Failing that, are any of your fixtures set to self terminate - (Sounds like a Sci-Fi film doesn't it???) Maybe a menu setting, a DIP switch or whatever? HTH Jim Link to comment Share on other sites More sharing options...
dmoffat Posted December 6, 2009 Share Posted December 6, 2009 BR wiki states "If the addition of a terminator causes problems in your chain, it is likely down to poor quality DMX Cable. Due to the nature of the DMX protocol, the devices are very sensitive to the quality of the cable and connectors, and misuse of this equipment can cause problems. " Are you using correct 120 ohm DMX cable? Link to comment Share on other sites More sharing options...
pritch Posted December 6, 2009 Share Posted December 6, 2009 I asked vaguely the same question myself, earlier in the year (although I'd already tracked down and rectified the fault, and was just wondering why it happened) http://www.blue-room.org.uk/index.php?show...c=33964&hl= Link to comment Share on other sites More sharing options...
Blaize110 Posted December 6, 2009 Author Share Posted December 6, 2009 Thanks everyone. Just read Jim's other post and it all makes sense now. I will check all my cables when I take it all down. Probably find a break or bad cable somewhere. Link to comment Share on other sites More sharing options...
LXbydesign Posted December 6, 2009 Share Posted December 6, 2009 Glad to see its mostly LED gear otherwise if I was your parents, id be passing a third of the months leccy bill onto you!! :) Link to comment Share on other sites More sharing options...
Blaize110 Posted December 6, 2009 Author Share Posted December 6, 2009 Glad to see its mostly LED gear otherwise if I was your parents, id be passing a third of the months leccy bill onto you!! :) Yeah, I did think about that and decided not to use parcans :P. Saves money on lamps and gel too. The only non-LED thing is a couple of short strings of fairy lights on the dimmer. It's also only on for a small proportion of the day. EDIT: Bulb = thing in the ground :P Link to comment Share on other sites More sharing options...
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