DMX Basics: Scrollers

[Musicman56]

I've just begun to take an interest in the DMX control system. For the next show that I'm doing, I was hoping to use DMX color scrollers. I understand the basic concepts of DMX, but I'm not sure how to execute them.

So here's the process as I understand it to be:

1. Set the DMX channel for the scrollers (for this show, they'd all be running off of the same channel, so I guess I could arbitrarily call it 1).

2. Daisy chain the scrollers together and plug in the power sources. Is a terminator necessary?

3. Run a DMX cable to our board (an ETC Express 48/96)

4. Now this is where I become totally lost. How do I go about assigning DMX channel 1 to one of my channels on the light board (I assume this is a different procedure for different boards)?

Thats the system as far as I understand it. I know that I'm probably wrong somewhere in here, so any advice would be greatly appreciated.

[JWilsonLX]

Things could change based on what kind of scrollers you're using, but the command should be as follows(assuming your scrollers are in universe 2):

[Patch][513][Enter][95][Enter][Stage]

Channel 95 will be the control channel for the scrollers. It can be any number you want, I just like 95 because it's the second to last physical handle(I usually save 96 for house lights).

[mstaylor]

How many dimmers are you using? The Express has two universes and as JWILSON says, it is best to put the scrollers in the second universe. The second starts at 513. If you are going to make all the scrollers do the same thing, just address all of them to the same address,513. Patch it to whatever dimmer you wish.
Doug Fleenor Design - DMX Information
In the top right are several articles that will explain more about how DMX actually works. Let us know if you need help hooking your scroller circuits. Just remember not to run the PSU off the dimmers.

[derekleffew]

...If you are going to make all the scrollers do the same thing, just address all of them to the same address,513. ...

Umm... the thumbwheel or dipswitch only goes to 512.

...Patch it to whatever dimmer you wish. ...

Should read channel. The "dimmer" number is determined by the address of the unit, and the port (DMX1, DMX2) into which it is plugged.

...4. Now this is where I become totally lost. How do I go about assigning DMX channel 1 to one of my channels on the light board (I assume this is a different procedure for different boards)? ...

Do you currently patch dimmers to channels on your Express 48/96? I'm guessing no, but scrollers can be assigned the same way. See chapter 4 of the Express 48/96 User Manual.pdf. You might also consider page 54, Independent Channels. It's probably a good idea to set channels controlling scrollers to Independent so the gelstring is not affected by the Grandmaster.

You'll also need a chart like this one, so you can quickly access the desired color.

[TheDonkey]

Address your scrollers to 1 and plug them into the second universe jack on the back of the console.
Then when patching on the console, as Wilson said,
[Patch][513][Enter][95][Enter][Stage]

512 is the last DMX channel in universe 1 so 513 is channel 1 in universe 2.

As far as plugging the scrollers in, you daisychain them with the 4pin data/power cable then run a single longer cable from the last light back to the power suppoly (making a loop..), although not always 100% mandatory but very highly recommended you should plug a DMX terminator into the DMX Out on the scroller power supply.

[mstaylor]

Umm... the thumbwheel or dipswitch only goes to 512.

Should read channel. The "dimmer" number is determined by the address of the unit, and the port (DMX1, DMX2) into which it is plugged.

I have to break myself of the habit. I keep saying dimmer instead of channel. I am an old analog guy and I know the diference but new guys don't. Sorry.

[Musicman56]

Thanks for all of the responses. I've found them all very useful.

I still have a question about the patching aspect though.

[Patch][513][Enter][95][Enter][Stage]

Wouldn't this only patch dimmer 513 to channel 95? Do you have to assign a dmx channel to a dimmer?

Thats where I get confused I guess is the relationship between the DMX channel, the dimmer, and then the channel on the board.

And also why is it suggested that I use the second universe?

[Scarrgo]

Do you understand how to patch a dimmer to channel? It is the same process for a scroller.
This example is if everything is in the output (1-512)
1. dimmer 1 (enter) channel 1(enter) (S4 on first Elec.)
2.Scroller on S4; address 1 would be patched by: dimmer 1 (enter) Channel 101 (enter)
If you are putting the scrollers into the second output(513-1024)
than you would patch the scroller in this fashion:
1. dimmer 1 (enter) channel 1(enter) (S4 on first Elec.)
2.Scroller on S4; address 1 would be patched by: dimmer 513 (enter) Channel 101 (enter)
you would than have the fixture(S4) on channel 1 and the scroller on channel 101
I think of it this way, the scroller or any other device that does not need a physical dimmer to operate, than in my mind it uses a virtual dimmer. It just works for me
I hope this helps...
Sean...

Thanks for all of the responses. I've found them all very useful.

I still have a question about the patching aspect though.



Wouldn't this only patch dimmer 513 to channel 95? Do you have to assign a dmx channel to a dimmer?

Thats where I get confused I guess is the relationship between the DMX channel, the dimmer, and then the channel on the board.

[Musicman56]

Sorry, I'm still slightly confused.

I know how to patch a dimmer to a channel.

So say that I want to patch dimmer 1 to channel 1. But then I want to patch address 1 to channel 2. If I used the patch function for both, when I went to patch in the address, wouldn't it move dimmer 1 over to channel 2 and take it off 1? Could I avoid this whole problem by using a channel number for a dimmer we don't have (i.e. we only have 204 dimmers, so if I patched 300, then it would be the dmx address?)

Sorry, I'm just really confused as to how the patching works. Because how I understand it, the system would confuse dimmer and address numbers.

[JWilsonLX]

So say that I want to patch dimmer 1 to channel 1. But then I want to patch address 1 to channel 2. If I used the patch function for both, when I went to patch in the address, wouldn't it move dimmer 1 over to channel 2 and take it off 1?

Address 1 and dimmer 1 are the same thing, as far as the light board is concerned.

I think the disconnect here is a result of how the Express is presenting things to you. In current generation ETC consoles, you no longer patch a dimmer to a channel as you do on Express(ion) series consoles. Instead, you patch an address to a channel. That address can be tied to a dimmer, a scroller, a moving light parameter, anything. When you patch dimmer one on your Express, pretend you're patching address 1, which just happens to be a dimmer.

That being said, what you said is true IF you're running your scrollers out of the same universe as your dimmers. If this is the case, readdressing your scrollers to 300 would do the trick. If your scollers are in universe 2, they won't be address 1, they'll be address 513(512(because you're in universe 2) + 1(address on the scoller)).

Hopefully this helps?

[derekleffew]

Sorry, I'm still slightly confused.
I know how to patch a dimmer to a channel. ...

Don't let the nomenclature confuse you. The Express(ion) software was written at a time when every DMX slot (today called output or address) was thought of as a "dimmer". In 1986, no one thought DMX512 would ever be used to control anything other than dimmers. To those consoles (ignoring the moving light patch for the moment), "DMX channel" is a dimmer number, that may or may not be a dimmer. A 48-way dimmer rack will take 48 DMX channels. A moving light may take 24 "DMX channels," but only one of them controls intensity. Some scrollers take two DMX channels--the first is the gelstring position and the second is the fan speed. A "control channel" exists only in the console and can be whatever number you want it to be. Some consoles (Hog) call this a "User number." Eos/Ion/Element use "channel" to mean 1) A dimmer or dimmers with the same control or 2) A complete moving light, no matter how many DMX slots it uses.

[JChenault]

How many dimmers are you using? The Express has two universes and as JWILSON says, it is best to put the scrollers in the second universe. The second starts at 513. If you are going to make all the scrollers do the same thing, just address all of them to the same address,513. Patch it to whatever dimmer you wish.

Just to clarify - the second DMX socket on the back of the express is, by default, set to 513. You can set it to some other starting address. For example, if your board fries it's DMX output chip, you can set the second socket to start at 1 and your show will happily run until you can get the board serviced.

Now I honestly don't remember where in the setup screen this is. The only time I needed it I was on the phone with my local tech support person who walked me through it. But it was not too hard to find and it saved my life. Just wanted to share the information.

[doctrjohn]

Now I honestly don't remember where in the setup screen this is.

You would press [Setup] then [2] [Enter] for Output Configuration. On this screen you will be able to select the start address for each output port as well as the DMX transmission rate.

Best,
John

[Musicman56]

Thanks everyone. I think you've cleared it up. I didn't know that dimmers were connected by DMX thats where I got confused.

So to clarify, if I wanted to use address 1. In order to control that address, I would patch dimmer 1 to channel 1. In effect, channel one would now control both whatever fixture (if any) would be plugged into dimmer 1 and also anything running on DMX channel 1.

Therefore I could patch dimmer 205 (we have 204 dimmers) to channel 1 and then only have to control address 205 and not dimmer 205, since dimmer 205 is not there.

Basically the board is dumb. I tell it I want address 1 controlled and it goes and finds whatever is in address 1, not caring if it may be a dimmer or a scroller or whatever is plugged in. Is that about right?

Thanks!

[mstaylor]

The board sends the information for the whole 512 universe and each device reads whatever is on that address number. Say your dimmers are 1-96, as the info is sent each dimmer is told what to do. The same is true for your scrollers, whatever you address it to, it receives the whole packet but it only reads the corresponding address.

[icewolf08]

Thanks everyone. I think you've cleared it up. I didn't know that dimmers were connected by DMX thats where I got confused.

So to clarify, if I wanted to use address 1. In order to control that address, I would patch dimmer 1 to channel 1. In effect, channel one would now control both whatever fixture (if any) would be plugged into dimmer 1 and also anything running on DMX channel 1.

Therefore I could patch dimmer 205 (we have 204 dimmers) to channel 1 and then only have to control address 205 and not dimmer 205, since dimmer 205 is not there.

Basically the board is dumb. I tell it I want address 1 controlled and it goes and finds whatever is in address 1, not caring if it may be a dimmer or a scroller or whatever is plugged in. Is that about right?

Thanks!

Yes and no.

Think of it like this: A single DMX line can carry data to 512 addresses, this is called a "Universe". An address can be a single dimmer, or you can have a complicated moving light that requires 20 addresses. So, you could have 512 single dimmers on one DMX Universe or you could have 16 moving lights that each require 32 addresses to operate.

Now, each device, be it a dimmer or a moving light or a scroller is essentially dumb. When you give it an address, it sits and listens to the DMX data going by and it counts the chunks of information. So, if your scroller is addressed as 145 it will count along the data stream and when it hears the 145th data chunk it does whatever that piece of information tells it to.

Now, the data that comes down each Universe is only 1-512. So, you can have a device on universe one that has an address of 1 and a device on universe 2 that has an address of 1. The console differentiates between the universes by calling universe 2 address 1 513. You would never actually address a device is 513 though.

Thusly, you are correct, if you had your scrollers plugged into the same DMX line as your dimmers and you had the scrollers addressed as 1, then they would come on ad the same time as dimmer 1. However, if you have them in universe 2, then they don't overlap as their true address is 513 even though the address on the device is 1.

I would also consider not having all your scrollers addressed the same unless you are going to patch all the lights they are on into the same channel. If you are using separate channels for the lights, use separate channels for the scrollers. It keeps your options open. If you want to then be able to control them together, make a group or a sub for them.

[xander]

I would also consider not having all your scrollers addressed the same unless you are going to patch all the lights they are on into the same channel. If you are using separate channels for the lights, use separate channels for the scrollers. It keeps your options open. If you want to then be able to control them together, make a group or a sub for them.

I think this might have something to do with the fact that he doesn't have enough channels to begin with. He has 204 dimmers and only 192 channels. Your point is very valid, I would want more control, but he has to make some sacrifices somewhere, so maybe that is a choice he made.

[icewolf08]

I think this might have something to do with the fact that he doesn't have enough channels to begin with. He has 204 dimmers and only 192 channels. Your point is very valid, I would want more control, but he has to make some sacrifices somewhere, so maybe that is a choice he made.

Yeah, that's true, I forget these things having not used an Express in a long time. I will admit it seems like a goofy thing to do, putting a console with fewer channels than there are dimmers, usually it is the other way around.

[xander]

Going back on what I myself said, you might want to think about addressing all of your scrollers individually, like has been said. I would do this because you can still patch them all to the same channel, if that's something that you want to do, but you could also separate them out in the future if you wanted to without having to actually go up to the units and physically readdressing them. Just a simple swap in the soft patch and you can have individual control.

-Tim

[Musicman56]

Thanks for all of your help everyone.

As far as the separation of the scrollers goes, I'm not quite sure what I'm going to do. At this point, I'm leaning towards having my 8 scrollers in 2 groups of four. That way I have some flexibility, but it also keeps me from wanting to do too much, because I tend to do that

But thanks again, and all your comments have been greatly appreciated!