DMX Issue?

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DMX Issue?

Postby Derno24 » 12 May 2011, 18:22

I will start by saying I am using the newest version of show express with a 512 plus and am controlling 5 color rails and 4 color strips. My problem is that when I get the cable and plug fixture # 8 in the lights go crazy. Doesn't matter the order or cable same thing happens. What am I missing?
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Re: DMX Issue?

Postby Pink LD » 12 May 2011, 18:56

Let me ask for clarification:
- It's always the eighth fixture?
- You say that its not the cable, no matter how you daisy chain one fixture to another its when you get to the 8th fixture it goes crazy?

Well here are my first thoughts: If its the same fixture each time than you have something errant in your programme for that scene. Double check the scene, what is activated and what is not.
It could be an XLR thats bad or a bad input/output jack on the fixture. My output jacks on many fixtures are prone to wear as the receptacles on the fixture widen on inexpensive XLR jacks and before you know it you have lost the ground, the send or return line.
The problem I find is when I have a bad jack for some reason I get faulty data going both ways and the whole rig goes on the fritz making troubleshooting a real pain in the butt as you have to half the rig to see which half is failing, then half the failing side, and by half and half again until you narrow in on the failing fixture, jack or cable.
I also carry these (See picture) to bypass bad jacks when I find one and use it to bypass a faulty fixture jack until I can replace it.
Put one of the males onto your input of your fixture and then send your daisy chain thru the other two plugs. Works like a treat and has saved my butt too many times to count.
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Re: DMX Issue?

Postby Derno24 » 12 May 2011, 20:26

When I mean 8th fixture it is the physical number of units not the eight one pluged in. meaning I have even juggled the units to make sure the unit itself isn't bad I even checked the programming by leaving the addressing alone and jumping over a fixture to see if that is right. It acts like there is a bad cable, but there isn't as I have switched them several times.

My question would be does it matter how they are numbered in the daisy chain? Meaning do they have o go up in order or can you have DMX address 7 be the first fixture and DMX address 4 the next? Also could it be a termination issue? I am running to almost 170 ft of cable.
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Re: DMX Issue?

Postby Pink LD » 13 May 2011, 02:27

What order the fixtures are in, in the daisy chain makes no matter. You could have unit 1, 7, 6, 3, 2 etc down your daisy chain. You just cant split a daisy chain unless you use a proper DMX Splitter and you shouldn't run the daisy chain in a loop.
I can run 40 of my fixtures up to 300 feet of cable before they will start getting buggy. But at 250+ runs I always use a splitter myself. Of course now that I own several splitters I just use them all the time.
A terminator is always worth a try from what I hear. Personally I have never had a problem solved by the use of one and I don't use them myself. I do always carry one in the off chance that it will solve a problem but in 500 shows I'm still waiting for one to be my solution...
Do your fixtures have multiple mode settings? Perhaps one fixture is in 7 ch mode, for example and the others in 5 ch mode. If you have them addressed in the program as though they are 5 ch fixtures, your 7 ch would be overlapped.
(Note: I don't know exactly what fixtures you have so I don't know how many channeled they are or how many modes they have, so my previous sentence is an example.)

On another note: Have you used the "Patch" program? Do you have an erroneous patch buggering up the works? Have you fired up the DMX setting and turned on "Show DMX levels" to see what is actually going on?
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Re: DMX Issue?

Postby Derno24 » 14 May 2011, 21:02

I am running them properly in a daisy chain and I am using 5 Color Rails and 4 Color strips. The strips have only one dmx mode and all the rails are set to 7 channel mode and set right. I have tried multiple jumps to check and see if it is wiring or even the fixture. If I jump a fixture and move to the next I still get the same thing right at 7 I am fine got to # 8 and bang. I am using the latest showexpress software for a Mac and I haven't tried the show DMX levels, but I will do so tonight. I went out and installed a terminator just for giggles and no better. Could it be the xpress 512 plus I am using? Just seems kinda odd that the number of units not the run has been dictating to me if it is working or not. I have tried all the fixtures indiviually and they respond to commands while hooked up. Any other thoughts?
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Re: DMX Issue?

Postby Derno24 » 15 May 2011, 02:33

I also looked at the DMX levels and they are good also.
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Re: DMX Issue?

Postby Pink LD » 15 May 2011, 09:48

I have to say I am stumped at this point. I am not a Mac user so I can't say if its a bug on that OS but I'd expect more people would be complaining about it if it is.
There is a classic "Turn it off, turn it on..." solution that is always worth a try when seemingly all else fails and I had reasonable success with it over the years: Uninstall the software, your lighting scenes, 3D, setup etc are stored separately so you wont lose those unless you delete them manually. Still make a backup just to be safe, use the export program. Then download the current stable version, I think 6.27, re-install, reinstall your drivers for USB DMX hub you are using. It'll take 15 minutes but its worth a try.
Sorry I couldn't narrow it down or solve it yet. Let me know what happens. I'll be around for a couple more days before I am offline for a week.
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Re: DMX Issue?

Postby tomrbland » 15 May 2011, 23:35

I'm afraid that I can't see how the controller could be at fault. It does not "see" fixtures, it just sends values to DMX addresses. It must be something in the setup of the system, without seeing it it's hard to work out what it might be. The only thing I can suggest has already been suggested - try and swap around as much of the equipment as you can, fixtures, cables... everything in a different order. See if the problem still occurs in the same place.

Sorry I can't be of more help.

Have you tried starting again with a fresh show in the software?
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Re: DMX Issue?

Postby DJ 3pm » 16 May 2011, 12:39

This may be a dumb question, but are you keeping the cables in the same order each time when shuffling the order of your fixtures?

Before getting ShowXpress I was using a Chuavet DMX-7 controller. Got to a gig once and plugged lights in and they went all sorts of crazy. I unplugged the controller and let them go in standalone that night. Turns out there was a switch on the back of the controller to switch the polarity of the signal: this accidentally got switched and the lights all worked fine.

What I'm getting at is maybe you have a cable that has the +/- leads switched or something.
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Re: DMX Issue?

Postby Derno24 » 16 May 2011, 17:20

I have juggled all the cables and fixtures numerous times so I am wondering if it could be just a weak signal from either the xpress 512 or one of the fixtures. I will try the software. I am thinking about getting a data stream 4 to split the signal up for the time being any thoughts?
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