Scroller problem

[RJMS]

I am checking to see if anyone here has experienced a similar problem with scrollers or perhaps any piece of DMX controlled gear.

I am having a strange recurring problem on a scroller run. It has four scrollers on it, 2 Smart Color and 2 Smart Color Pros. Every so often the scroller that is the last unit in the run (and which has a standard four pin DMX terminating connector on it) will receive a change order from my ETC Element and will then proceed to run wild. It will scroll end to end repeatedly, and nothing short of turning off the light board (which also cuts power to the scrollers) will stop it from doing so. It happened in every show last season, and though I have done extensive trouble shooting I have not been able to prevent the problem from occurring. So far I am blaming the ETC Element, mainly because replacing the unit with another one does not make the problem go away, and it always happens on the same cue in the show. The only thing I have not been able to change is the Element, I don't have a spare one hanging around.

 

[coldnorth57]

I use 8 smart color and have found out that you must run from your last scroller back to your power supply so that all scrollers get enough power to run properly

 

[starksk]

I am sure kelite or another one of the great Apollo guys will be over to this thread shortly, but in the mean time, have you tried running a return line instead of a terminator at the end of the line?

I am very skeptical that the Element is the cause of this behaviour. Unless you have an effect applied to the last scroller unit only, the Element will send only the value that corresponds to the selected frame. When you change the frame, it will send the new value. One way to eliminate the console as the cause is to swap the last scroller with one that is not exhibiting the problem, but do not change the address. If the problem moves with the scroller, then you know that the console is sending funky data to that address. If the problem stays at the end of the line, the console is not cause of the issue.

Hope this helps...

 

[BryanKacz]

I have that problem all the time with the smart colors, it's always caused by someone not running the return line from the last scroller to the power supply

 

[Footer]

I have that problem all the time with the smart colors, it's always caused by someone not running the return line from the last scroller to the power supply

Or a power problem. During a cue, especially if its a large move, the last unit on the chain can reset if there is enough of a power drop. When it resets, it runs head to tail just like its starting up. Run a return line as others have said. Have you tried throwing the units into "slow"? How long are the cable runs? What power supply are you using?

 

[Kelite]

Since this thread appears to have died, I'm guessing the lack of a 4-pin return line (which is required for proper functioning) has been added.

With all 24V systems power is important, and a data terminator does nothing to assist maintaining line voltage. The use of a 4-pin return cable is listed repeatedly in the manual not for the purpose of selling more cable, but to keep these ghosting issues away.

I hope your system is up to speed (literally) RJMS! Please let me know if not-

(800)288-4626 Keith

 

[LXPlot]

Since this thread appears to have died, I'm guessing the lack of a 4-pin return line (which is required for proper functioning) has been added.

With all 24V systems power is important, and a data terminator does nothing to assist maintaining line voltage. The use of a 4-pin return cable is listed repeatedly in the manual not for the purpose of selling more cable, but to keep these ghosting issues away.

I hope your system is up to speed (literally) RJMS! Please let me know if not-

(800)288-4626 Keith

But what if one were to use something like this?

Without return power, how can we be sure that the problem will not happen to us?

 

[Lotos]

But what if one were to use something like this?

Without return power, how can we be sure that the problem will not happen to us?

You'll find that PSU is rated to power two scrollers.
I've successfully put three on it, without incident, but that's another issue...

Due to the way the PSU works (injecting power while passing the DMX straight through) it's different than a dedicated Scroller PSU.

THAT PSU is the only reason I can think of for a 4-Pin Terminator, as all other require a Home-Run

 

[Kelite]

Great thread- it's good to hear questions and answers regarding other 24V products.

Per the Apollo website re: Smart Power 75W-
Powers up to 1 MXR color mixer, 2 Smart Color scrollers, 5 Smart Move rotators, or a combination of these products.

A very determining factor involves cable run length and quality of cable, as higher impedance cable and/or cable which has been kinked or run over by equipment may have unseen damaged copper. All said, good quality cable and connectors in optimum condition provides optimum service.

Data Terminator? YES! This is one of the very few instances in which I can see that a 4 pin data terminator should be used.

Thanks guys, certainly appreciate your thoughts!

 

[derekleffew]

...Data Terminator? YES! This is one of the very few instances in which I can see that a 4 pin data terminator should be used. ...

And yet, there's nothing on the page that states an Apollo AC-DMX-120 (or equivalent) should/must be used with the Smart Power™ 75W Power Supply.

 

[Kelite]

Good point Derek- I've asked for this info to be added.

Thanks!