Intelligent Lighting Adjustment Problem

[blvrschurch]

Hey everyone,

Could use some help. I have a lighting system using around 25 intelligent light fixtures and around 30 conventional lights and two hazers. We use a WholeHog 1000 and an OptoSplitter 5X1 for DMX. We typically have around 5 songs that we do every Sunday service with saved scenes created throughout the week. We then save these scenes and may use them if we are doing the same song a couple of months later. They are saved in the Wholehog and with a floppy disk backup.

The problem we are having is with three intelligent fixtures. One of them is a MAC 600 wash. The other two are intellibeams. The problem is that when we turn on our system, these three lights (not all the time and sometimes it may only be one fixture) are out of position by about 5-15 degrees. The MAC 600 is usually off on the tilt by 12 degrees. And the technobeams are both off on the pan by about 3 to 5 degrees. This has been consistently the problem. We could have a week and everything is fine. We could have a week and one fixture is off. We could have a week with all three off or none at all. There seems to be no consistent pattern.

So any help would be greatly appreciated.
Blvrschurch

[blvrschurch]

Oh and btw -- none of the lights or the board are showing any error messages.

[petereit]

OK, lets cover the fundamentals first.

Are you using 100% DMX digital-rated data cabling on ALL your DMX signal paths? (As opposed to using audio XLR cable.)

CMN Player - DMX vs. XLR Cabling - There IS a difference!

Is your cable shielding grounded at the console end ONLY? (And for that matter, is your console grounded correctly?)

Is the last DMX device on EACH LEG off your OptoSplitter terminated with a termination switch or resistor with a value of 100 to 120 ohms between pins 2 and 3?

[blvrschurch]

Yes. I believe all three are correct. I know the OptoSplitter has a termination switch which is on. The console is grounded correctly. And we had all our cabling originally installed by a "professional" company and was told they are DMX digital cables. I would believe this to be true because we haven't had any problems with these lights until recently (about 6 months now). The system is 5 years old.

[petereit]

What changed "recently?"

[petereit]

Also, the OptoSplitter is just one device. I assume you have one or more chains hung off of it. Are the DMX fixtures at the end of each chain properly terminated?

[waynehoskins]

I wonder, could it be an issue related to tracking? Do you run the same set of cues each week, or do you have separate cue stacks for each song? Can you correctly home, locate, or whatever-they-call-it the fixtures?

[theatre4jc]

Originally Posted by petereit

Also, the OptoSplitter is just one device. I assume you have one or more chains hung off of it. Are the DMX fixtures at the end of each chain properly terminated?

I was under the impression that OptoSplitters acted as a self terminator for all of the splits it sent out.

[petereit]

Originally Posted by theatre4jc

I was under the impression that OptoSplitters acted as a self terminator for all of the splits it sent out.

That would seem to be at odds with the DMX specification. If I understand the function of the OptoSplitter, it serves as the end of the DMX signal chain that feeds it, and as such would need to be terminated. But it then serves as the head end of any chains that it feeds, so the last fixture at the end of each of it's signal chains would need to be properly terminated.

Also, if your OptoSplitter has a THRU outlet, that outlet is typically NOT amplified or optically isolated. If it is not being used, it must have a termination plug inserted. If the amplified, optoisolated outlets are not used, they do not need to be terminated.

[blvrschurch]

As far as tracking. I can home the fixture. But the home is off by the degrees mentioned before. The cue stacking we do is sometimes new or an old set of cues that we copied from a previous week/month. But even so, it doesn't seem like there is a relationship between stacks, because even the cues that I haven't copied, if I go to any of them (even earliest of 2 months ago), the lights are still out of calibration. So it seems like it's not related to the Hog.

The Optosplitter does terminate DMX signals, but I will have to look to see if the end fixtures are terminated. Honestly, I'm not sure about that.

However, I will say, we have had the system for five years, and nothing recently has changed other than we have added to hazers in the last year, and they are on a completely different dmx cable run directly to the optosplitter.

[waynehoskins]

Given that, my guess is it's a fixture problem. Dirty encoders come to mind. If their initial power-on calibration is off, then it thinks it's in the right place but really it's consistently some fixed amount off.

[Esoteric]

Yeah, I would start with the fixtures. Bad sensors, dirty encoders, failing motors are all possibilities.

Mike