lxkev Posted October 3, 2005 Share Posted October 3, 2005 Installed a DMX network last year. With: 1 * Celco splitter and 5 DMX lines out i.e. 1 Dimmers. 2 Roof. 3 scrollers. 4 stage. 5 Bar/house. All terminated. I used cable sutable for DMX (not mic cable) and all lines are terminated. However Once in a while it all goes a bit mad. i.e. a fixture on one line my flash, a mover on another line may start going "nutts". Ive tried diffrent desks, removed the splitter, but it still happens. ideas? Link to comment Share on other sites More sharing options...
Andrew C Posted October 3, 2005 Share Posted October 3, 2005 Couple of thoughts.1) Any motor control / supply cables running near yours? Particularly long parallel lengths.2) An intermittant eart somewhere in the system. Could be in your DMX lines or dimmers or mains plugs for something. If it is loosing / regaining earth this could cause wierd issues. Link to comment Share on other sites More sharing options...
Guest lightnix Posted October 3, 2005 Share Posted October 3, 2005 It sounds similar to something I had happen once. There were no movers (just some Martin Robocolours), but every few minutes a channel would flash or dip. We were using an Avo Pearl through a Celco DMX box and into the hotel's dimmer rack (also Celco). After doing several things, including changing all the DMX runs and playing with the settings on the desk, we found out that the Celco decoder "didn't like" the DMX being put out by the Pearl. The problem was cured by putting an XTBA splitter box between the desk and the racks, which cleaned up the DMX signal to USITT standard. Link to comment Share on other sites More sharing options...
lxkev Posted October 3, 2005 Author Share Posted October 3, 2005 No motor control / supply cables running near any of the DMX. How can I test for a intermittant earth? Link to comment Share on other sites More sharing options...
griff Posted October 3, 2005 Share Posted October 3, 2005 is the mains common to al areas of DMX Link to comment Share on other sites More sharing options...
lxkev Posted October 3, 2005 Author Share Posted October 3, 2005 Lots of diffrent mains...... Link to comment Share on other sites More sharing options...
danjshelton Posted October 3, 2005 Share Posted October 3, 2005 It sounds similar to something I had happen once. There were no movers (just some Martin Robocolours), but every few minutes a channel would flash or dip. We were using an Avo Pearl through a Celco DMX box and into the hotel's dimmer rack (also Celco). After doing several things, including changing all the DMX runs and playing with the settings on the desk, we found out that the Celco decoder "didn't like" the DMX being put out by the Pearl. The problem was cured by putting an XTBA splitter box between the desk and the racks, which cleaned up the DMX signal to USITT standard. I had something similar about a month ago, a one night gig in a hotel and pearl to celco splitters, then onto dimmers/movers. We found that we we're getting some dodgy data on one of the lines (the dimmer line), and presumed it was the pearl (which wasn't in the best of conditions!), but this could explain what the issue was, if the celco splitters don't like the pearls data. So Kev, what desk are you using and also what length is the run? As you said you have tried bypassing the splitter that would have been one of my first checks, but you say it still occurs without the splitter. Cheers Dan Link to comment Share on other sites More sharing options...
steveo Posted October 3, 2005 Share Posted October 3, 2005 I presume there is no analogue converter or D54 convertor or anything like that. Try disconnecting the terminator. Sounds daft but sometimes the DMX confuses itself when terminated Could just be the wonders of DMX mmmmmmmmm Link to comment Share on other sites More sharing options...
lxkev Posted October 3, 2005 Author Share Posted October 3, 2005 Its a zero 88 frog 2, but had probs with other desks...each cable run is a max of 30 metersabout 4 fixtures per line Link to comment Share on other sites More sharing options...
griff Posted October 3, 2005 Share Posted October 3, 2005 had a similar problem with movers 2 different mains.seemed to be some earth fault and DMX got rid of it by removing earth on 1 suply Link to comment Share on other sites More sharing options...
andy jackson Posted October 3, 2005 Share Posted October 3, 2005 I have a similar problem here but on the scroller line, it only happens once a month or so so I just live with it! I think it livens up Aykebourn pieces when all the colours of the rainbow appear. I know its lazy but I will look into the problem when I service the scrollers! All I can think of is earth or a line fault but I have no idea where! just praying that its not in the internal wiring of the building! Andy Link to comment Share on other sites More sharing options...
Oovis Posted October 3, 2005 Share Posted October 3, 2005 had a similar problem with movers 2 different mains.seemed to be some earth fault and DMX got rid of it by removing earth on 1 suply Eek! If your equipment is Class 1 (Earthed) and you remove the earth connection to solve a data problem you could end up trying to justify yourself to a coroner, should anything go wrong. Earths are there for a reason. Link to comment Share on other sites More sharing options...
gareth Posted October 3, 2005 Share Posted October 3, 2005 had a similar problem with movers 2 different mains.seemed to be some earth fault and DMX got rid of it by removing earth on 1 suplyEh?! Are you saying that you lifted the earth on the mains supply to some of your moving lights? Sounds like you're an accident waiting to happen .... Link to comment Share on other sites More sharing options...
griff Posted October 3, 2005 Share Posted October 3, 2005 sorted out the fault for one gig not a recomended solution Link to comment Share on other sites More sharing options...
bright spark Posted October 3, 2005 Share Posted October 3, 2005 I would far rather have no mover than a dangerous one. Any decent LD would use a generic base for key lighting and main, with moving lights over the top - unless its your whole mover rig, I don't see why you can't loose a mover or two. Link to comment Share on other sites More sharing options...
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