Strange DMX/Moving Light Issues

[chrispo86]

Alright, I'm really stumped on this one. I'm doing a show right now where we are running 2 MAC 300's, 3 MAC 250's, and 2 Antari ICE foggers all on universe 2 of an Express 48/96. We've done this setup a handful of times before and have never had an issue. These items are the only thing on this universe. All of the movers are working as intended (not quite, more on that in a moment), but I'm having some strange issues with the addressing on the foggers.

The dip switches are set on the foggers to addresses 116 and 117. On the console, the foggers are set up using the moving light setup onto 2/116 and 2/117, patched to channels 116 and 117. However, when we put 116 and 117 on nothing happened. By matter of chance, we noticed that when we turned something else on we got fog. So, by process of elimination, we found that the the foggers are showing up on dimmers 756 and 629 respectively. Now the 629 makes sense to me, 117+512(universe 2) = 629. Where on earth does 756 come from? I've been trying to wrap my mind around this for days, and can't figure it out. We have it working as is, so it's not a pressing matter, and we've never had this issue before, but I'm really stumped, and now curious to find an answer. Any takers?


Now as I said the movers are working as expected, but there's a catch. There is one fixture that we keep having errors with. These are rentals, and for some reason, every single show we rent these things, the fixture that we put in this position on the stage starts having errors like there's no tomorrow. The guy we rent from swears we're doing something wrong. And that's my question, is there really anything that we can be doing wrong? I'm talking errors like Lamp Errors, Gobo Errors, Feedback Error, Pan Errors, etc... The strange part is, it's always the fixture in this one location. The DMX feed is a straight through from the console daisy chained through our DMX toys. This is usually first on the chain, though this time around it's the last. I said switch power outlets, maybe it's not clean? We're still getting errors. Any ideas on that one? (I'm not expecting much help on this because it's hard to diagnose without being there, but just figured I'd throw it out there).

Thanks!!

[len]

As for the foggers, I usually just patch them into addresses like 510, 512,etc. My guess is that you've got some goofy patch in your board, and I can't help you with that.

As for all the errors, the first guess I have is that you leave the cable up and just rent the lights to hang in those positions? Yes? If so, my guess would be you have a bad data cable that's sending oddball info. Or it could be power, but I'm guessing it's data.

The first solution on that would be to power all units down, run a single data line straight to the wonky fixture, and then power it up. That's always the first place to look.

[fredthe]

As Len suggested, sounds like a bad cable. Either one with one of the data lines bad, or mis-wired. Also, the usual question, is it properly terminated? Also, you aren't trying to power it from a dimmer, are you? Run a single cable to that fixture alone (and terminate) and see what happens.

As to the odd address on your fogger... assuming that you don't have some funny patching in your board, I note that it's address is a suspicious distance from where it should be (128) Is the address set by dip-switch? It may be that a switch is in the wrong position, or has gone bad.

-Fred

[chrispo86]

Okay, responding to the comments about the fixtures. It's been on a new DMX line every show, also rented from the same company as the lights. The chain is terminated properly and no the fixtures are not being plugged into dimmers. I haven't had the chance to try running a single cable to the fixture and at this point the director doesn't want me touching anything in the rest of the chain (i.e. disconnecting it) in fear that something else will get messed up.

The director and tech advisors (this is my old high school I help out at, by the way) are convinced we're doing something wrong, but really, is there actually anything we could be doing wrong? Correct me if I'm mistaken, but doesn't it really just come down to plugging it in and controlling it from the console? The wiring is really pretty hard to screw up, and considering everything else on the chain works, I would think that's not the issue. It's not going to be a patch issue, because it works fine up until we get an error at a seemingly random point in time. I'm going to say that the line between the booth and the stage are not a problem either as it was just replaced about a year and a half ago and we had these problems prior to that anyway. Basically I see it being a problem with the rental board outputting faulty DMX signals, or, my personal belief, that these fixtures aren't kept in as good shape as we're told. I can't figure out what else would be part of the equation.


As for the fogger being 128 from where it should be, that's interesting, I didn't catch that coincidence. I've triple checked the dip switches on the fixture to make sure they're correct (though now I'm second guessing myself), but maybe one of the dip switches is broken? I don't know how likely of a scenario that is, but you're right, that is a suspicious coincidence. That particular machine is the one we own, so after this show I'll have to investigate and see if I change the address if it's still off by 128. Thanks for the catch!

[JD]

Dip switch may be dirty. The switches can have their contacts oxidize inside and make intermittent contact. Try flipping the switches back and forth (esp #128) several times then power down the fogger and power it back up. Operating the switches like that can clean the contacts a bit.

[xander]

I don't have any knew advice about the fogged, but it sounds like the 128 dipswitch is a good thing to investigate. As for the movers, you said that it always happens to the fixture that is in a certain position so I would swap the fixture with one of the other ones and swap there address as well. Does the problem go with the fixture or stay at that position? If the problem persists with the new fixture in that position, I would change it's address. If the problem persists I would say it isn't the board. Like everyone else is saying it sounds like a bad cable. You don't think that is the case so I ask, do you have an exceptionally long run or a very large number of devices on one universe? If you aren't pushing the limits of DMX, are positive the cables are in perfect working order (it's not mic cable is it?!), and the problem is specific and limited to that geographical location, think about the environment around it. Is it small and enclosed leading to poor air circulation and overheating?is the A/C you using bad in some way? Is there a leak in the ceiling dripping on the fixture? Stuff like that. Sorry I can't be of more help.

Tim

[Esoteric]

Yeah without being able to see it or even troubleshoot it properly, it would be very hard to tell.

I would begin with running a cable direct to the light (as short of a cable as possible). Then I would push it further down the DMX line. Then I would remove the unit from its hang point and try it on the floor. Then I would try another unit in its spot.

Usually from those tests you tell what the problem is. Without them, you are kind of stuck.

Mike

[mstaylor]

One of the things I would do in your list of troubleshooting is disconnect the in and out cable of the trouble light, connect them together and see if the new first instrument inherets the problem.

[len]

"Geographic location" triggered the random thought that maybe there's a return or some vent blowing on it, so it's getting too hot/cold, whatever.

[mstaylor]

To be honest with you, I believe you have the answer. If it is a different light each time and different cable each time, the most likely answer is your vent problem or a board problem. It sounds like they are getting a rental board to run the movers, the question is is it the sam board.