Ion Scroller Freakout

[Colin]

Going into first tech with Smart Color scrollers controlled by our new Ion, and having this problem:

I started out running all my conventional fixtures and the scrollers in universe 1. We only have one universe distributed through our ancient space, so I have never split things up and never had to with the old Express. This time, I get a fluctuating range of freakouts from the scrollers-- varying from a little jitter to no response whatsoever. Swap them to universe 2 (with my last too-short 5-pin stretched like a circus slackline in order to reach from tech table to scroller power supply) and they work great. Swap everything else to universe 2 as well and they freak again.

So apparently, my Ion refuses to control scrollers unless they're in a separate universe. It's been a long day but I'm pretty certain I've ruled out faults everywhere else. Seems crazy that Ion would cause issues where Express didn't. Any ideas?

 

[Lextech]

Sounds like a termination problem. Have you terminated the scroller PSU? Are they daisy chained out of a dimmer pack?

 

[MikeJ]

Most scrollers(at least last time I used scrollers; its been a while) "require" a return line from your last scroller back to the PSU. This is basically how you terminate them. I have never run a return line, but just like terminating fixtures, a lot of the time it makes no difference, but sometimes you really need to. Its best practice just to terminate to begin with and avoid potential problems.

Id be willing to bet that the the DMX timing from the Ion is quite a bit "faster" compared to the express, and that's why you are only now seeing this problem.

 

[sk8rsdad]

Also be sure to disable RDM.

 

[Colin]

Thanks guys, but your suggestions are already implemented. I have return lines in place, shorter cable runs than usual and well under Apollo's suggested maximum, have disabled RDM and switched DMX speed down to slow. I'd expect to still see some symptoms with the scrollers in their own universe too if it were a cabling/terminating/RDM issue or anything external to the console, but maybe I'm wrong.

 

[MikeJ]

Are the scrollers getting DMX in a chain comming through the dimmers? What kind of dimmers? Do yo have an opto-split you can run them through? Sometime different fixtures and dimmers can interact poorly with eachother, and I have seen this change between consoles types, with the same rig. Are there any other fixtures in that same dmx chain?

 

[sk8rsdad]

I've got an Ion with scrollers, dimmers, LEDS, hazers, foggers, and MLs in the same universe with nary a twitch from the scrollers. Is it possible you've enabled gel saver mode? Are there any devices on the run that might be sending something, like some LEDs with a master mode can do?

 

[Colin]

The rig is just conventionals powered from a legacy sensor rack, plus the scrollers, controlled by Ion. I guess I'll try to get an opto splitter rental ASAP and see if that works. Otherwise distributing a second universe to about 200' from the booth. Yuck.

 

[MNicolai]

Before you go renting anything, I'd temporarily move the console on-stage and connect the scrollers directly to the back of that and see if that resolves it. If so, something about the DMX distribution is wonky.

If you do need to run another DMX line from the booth, you could try using 3/5pin adapters to hijack an existing mic line to stage if you've got one. It's not ideal, and it's not likely your mic lines use DMX-grade data cable but it would probably work and might be more practical than using loose cable to get through the house and onto the stage.

 

[GreyWyvern]

Sorry, I'm kind of late to this, but a couple notes. First, the scrollers won't be affected by RDM being on or off and DMX refresh speed should not have any effect on them either. Second, the return line actually has less to do with data termination, which is good to do regardless, and much, much more to do with power. Without the return line, your power loop, well, it isn't a loop. The return line closes the loop and ensures all the units across the run are getting close to equal power regardless of their cable-foot distance from the power supply.
To get to trouble shooting... Are the scrollers twitching all the time, regardless of what frame they are in? Are they all twitching? Are they twitching in the same way or is it more random? How many DMX devices do you have on each line, keeping in mind the maximum is 32?

 

[JChenault]

To get to trouble shooting... Are the scrollers twitching all the time, regardless of what frame they are in? Are they all twitching? Are they twitching in the same way or is it more random? How many DMX devices do you have on each line, keeping in mind the maximum is 32?

Dave
Just to make sure I am not off base. A device ( for the 32 count) is the PSU not the scroller. Would this imply that if this is a problem all scroller son a PSU would twitch in unison?

 

[Colin]

Are the scrollers twitching all the time, regardless of what frame they are in? Are they all twitching? Are they twitching in the same way or is it more random? How many DMX devices do you have on each line, keeping in mind the maximum is 32?

They basically always twitch, but not in a perfectly regular fashion. I would call it random. I have just six scrollers running, three from each output on the PS. The issue began with the last scroller in one of those chains, and then soon spread to the rest. They don't all exhibit the same behavior at all times, but do all behave badly. Sometimes they will still respond to commands, sometimes not. The twitch is usually just a quarter frame or so, like until the scroll gets tension and then it goes backwards again, then immediately forwards and so on. Sometimes it will go a full frame in either direction. In terms of timing, the twitches are not always evenly spaced, but there is never much time between.

In the universe, I just have two sensor 96 racks and the six Smart Colors on one PS, plus there's a legacy Unison system in there.

I've picked up a long 5-pin to run a second universe for the scrollers and all is well. I haven't bothered yet (maybe once the show comes down) to swap the old Express back in, but I'd bet that they'll work fine again in that case too. The Ion is the only change since they last functioned. That's the part that is beyond my understanding. I've tried scrollers alone on both universes out of the Ion and they work fine, but when I output either universe to the facility's installed data distribution and try to run dimmers plus scrollers through that, no good. So that seems to point to an issue somewhere in the distribution, and yet the fact that Express (I think still) controls everything fine would point to an issue with Ion?...

 

[GreyWyvern]

Thanks for the response Colin. A couple questions I forgot to ask are, what power supply you are using and are the scrollers old Smart Colors, dip and rotary switches, or PROs, segmented LED display.
Scroller twitching can be caused by a "dirty" DMX signal with a really slow refresh rate. I highly doubt this would be the issue in your case since you are using an Ion and not a 12 channel Lightronics board. Bad cable could also be a cause. It is odd that you say it started on one and spread to the others. Do they still twitch when the console is not off or DMX is disconnected?

A device ( for the 32 count) is the PSU not the scroller.

John, we use the 6n137 chip, which is isolating, as the DMX transceiver in our Smart Powers, so that is correct. It is possible that other (likely older) power supplies do not use an isolating chip, so, in my understanding, the devices connected would count towards the device limit. This of course does not account for "newer", lower power chips that only count as 1/2, or even 1/4, of a device, therefore potentially doubling to quadrupling the maximum number of devices. However, that is a can of worms that need not be opened. Always safe to assume 32 is the magic number.

 

[Lextech]

Dave is the Smartpower's DMX line self terminating?

 

[GreyWyvern]

Dave is the Smartpower's DMX line self terminating?

The input/passthrough is not terminated. Is that what you are asking?
On the 4-pin inputs (return line connections) there is a terminator.

 

[Colin]

Thanks for the response Colin. A couple questions I forgot to ask are, what power supply you are using and are the scrollers old Smart Colors, dip and rotary switches, or PROs, segmented LED display.
Scroller twitching can be caused by a "dirty" DMX signal with a really slow refresh rate. I highly doubt this would be the issue in your case since you are using an Ion and not a 12 channel Lightronics board. Bad cable could also be a cause. It is odd that you say it started on one and spread to the others. Do they still twitch when the console is not off or DMX is disconnected?

These are non-PROs with rotary addressing, powered by a Smart Power 400W. Serial on the PS is 078122. I think everything is late 2007.

They don't twitch with console off or DMX disconnected.

As for the starting with one and spreading thing, it happened pretty quick so could have just been a coincidental lull in the ongoing but slightly irregular behavior. I saw that just one was twitching and went to swap the scroller and cable as a first step, which just took maybe two minutes, then a minute or so later they were all twitching. A while later they entirely stopped responding to the console (but still twitching) and then they started responding again for a while (still twitching) then not...

 

[WVTheatre]

Before you go renting anything, I'd temporarily move the console on-stage and connect the scrollers directly to the back of that and see if that resolves it. If so, something about the DMX distribution is wonky.

If you do need to run another DMX line from the booth, you could try using 3/5pin adapters to hijack an existing mic line to stage if you've got one. It's not ideal, and it's not likely your mic lines use DMX-grade data cable but it would probably work and might be more practical than using loose cable to get through the house and onto the stage.

I agree something must be wonky with the dmx distribution. There IS a limit on the number of devices that can be daisy chained via dmx, and can cause dmx data corruption/loss in some cases. We're running about 96 dimmers on U1 in our venue, as well as multiple Wybron scrollers. The only thing we have on U2 is our two intelligent lights located in the middle of the house (minus the dimmers).

 

[wmheath]

Have you tried changing the DMX output speed? There is an option in the shell to adjust the baud rate. Also, are you patching them as a two part fixture? On top of that, do you have the correct profile selected for the scroller?