DMX help

[Shawncfer]

Alright so I'm starting to get it now. But finaly I just wanna make sure I got this, according to kinkele, at the end of tv xlr cable, it will plug into dimmer 1, then from there, another smaller 5 pin xlr will come out dimmer 1 and into 2. Then out 2 and into 3 and etc. Once it gets to the end of the dimmer rack, it can then go to moving lights and pass through some of those and even then to those gel switchers that I can't think of the name right now and it can change the different gels. Pretty much anything cept pyro and laser? And I can just keep running it through as long as I have under 512 dimmers or whatever hooked up. And I know that the moving lights count for about 14 if those dmx channels so as long as everything combined is under 512?

[NickJones]

You got a bit lost...

at the end of a tv xlr cable, it will plug into dimmer 1

The cable is supposed to have a 5 Pin XLR adapter, looks like this, that is known as a DMX Cable,

Each device in the chan is given and "adress" like an email adress, and this means that when you send the signal to pull up channel 10 to 100%, whatever dimmer or mover is adressed to channel 10 will listen and do what it says, so the cable doesn't have to run to anything in any particular order.

Each device has an input and an output, meaning they can all be linked.

And the gel switchers are known as "Scrollers"

It's not used in Pyro as it doesn't have adequate saftey features.

Moving lights can use up to about 30 different channels.

Nick

[soundlight]

NickJones, I think he meant "the" not "tv". There's no "a" in his post.

Originally Posted by Shawncfer

Alright so I'm starting to get it now. But finaly I just wanna make sure I got this, according to kinkele, at the end of tv xlr cable, it will plug into dimmer 1, then from there, another smaller 5 pin xlr will come out dimmer 1 and into 2. Then out 2 and into 3 and etc. Once it gets to the end of the dimmer rack, it can then go to moving lights and pass through some of those and even then to those gel switchers that I can't think of the name right now and it can change the different gels. Pretty much anything cept pyro and laser? And I can just keep running it through as long as I have under 512 dimmers or whatever hooked up. And I know that the moving lights count for about 14 if those dmx channels so as long as everything combined is under 512?

Each individual dimmer in a rack does not take DMX. There is a processor in the rack that takes the DMX and tells each dimmer what to do via internal wiring and commands that are not DMX. You would not want to pay for DMX tranceiver electronics for every single channel of dimming you have! Each dimmer rack though does have DMX. If you have a bunch of eight-channel dimmers, each of these takes DMX. The first one "daisy chains" to the second one, second to the third, etc. So if you have 24 channels of dimming in a rack which has three 8-channel rackmount dimmers, you only need to connect each rackmount unit to eachother, not a cable between each of the 24 dimmers. And for something like a large ETC Sensor rack, an individual "CEM" (name of the internal processor for ETC Sensor dimmers) can control up to 96 dimmers.

This "daisy chaining" term that I'm talking about is the term for connecting one dimmer rack or fixture to the next dimmer rack or fixture by connecting the DMX out of one to the DMX in of another.

The length of a DMX signal chain (say, daisy chaining a whole bunch of moving lights together) is technically limited to 32 devices in one run of DMX (this is a limitation set in the standard, and should be followed to prevent weird signal issues from coming up).

If you have more than 32 devices (be that dimmers or moving lights or rotators or whatever), you have to use something called a DMX Optosplitter. The "opto" part of that is for the special optical isolation that's used to split the DMX. These devices can have anywhere from just two DMX outputs to at least 10. This way you can connect more devices to one DMX signal.

The gel switcher things you're talking about are scrollers. Most gel scrollers are powered from their own central power supply. This power supply takes a DMX input and a power input, and puts them both on the same 4-pin cable. This goes out and gets daisy chained to each of the scrollers so that they don't have to have individual power runs as well as DMX runs.

[Shawncfer]

Sorry I did mean the. I'm just typing on a phone so it auto corrects it.

So I got the basic idea that it runs through the dimmers and then through other stuff.

The only thing I messed up is that it doesnt go through each dimmer, instead a processor which then divides it amongst the dimmers. And then I can daisy chain through one processor of one dimmer rack to another processor of another dimmer rack and then it can go through those processors (if needing more than one) and into moving lights.

Now for the gel scrollers. Can it run through the dimmer processor and into the moving lights and then into the scrollers or do you need a separate board and DMX signal for the scrollers?
Posted via Mobile Device

[n1ist]

The order doesn't matter; the DMX chain can go to the dimmer processor and then to the movers, or it can go to the movers first. Each device has an address (usually set with dipswitches or up/down buttons on the device) that tells it which of the 512 channels start looking at. A splitter (1 cable in, many out) lets you get around the limitation of 32 devices per DMX chain (there's not enough "oomph" in the board to drive more than 32 things, and the splitter regenerates the signal).

Some gel scrollers take DMX directly; others have a special power supply box that takes DMX (and power, of course) and converts it into what the actual scrollers use, and connects to the scrollers with a special cable).

One other tidbit - at the end of a DMX chain (on whichever device is plugged in last), you need to terminate the signal, either with a terminator plug, or some devices have a switchable terminator. This makes sure the signal doesn't get any interference from reflections at the end.

As for the XLR connectors, the DMX standard specs a 5-pin XLR. Much lower-end gear uses a 3-pin XLR instead. Some stuff even uses RJ45 connectors. There are adapters that go between them. You need to use DMX cable, not regular mic cord, to ensure signal fidelity.

/mike

[Shawncfer]

Alright alright, but
still, can I run the same cable to the color scrollers? Or does it have to be a separate dmx signal from a different board? And was I right about you plug the 5pin xlr to the processor which then sends it to all the different dimmers? And what if I don't have anything plugged into a certain dimmer? Does it skip over that dimmer when giving addresses or does it still get an address in the 512 rangr and. Just don't patch it into my board?
Posted via Mobile Device

[GreyWyvern]

Originally Posted by Shawncfer

can I run the same cable to the color scrollers? Or does it have to be a separate dmx signal from a different board?

The same cable can't be run straight to the scrollers, but it doesn't have to be a seperate DMX signal from a different board (although it can be done that way). Scrollers use 4-pin data cable to get their signal which also supplies the power needed to operate them. The 5-pin cable you would daisy-chain from your other devices, would go into a power supply unit and could continue on to other devices. You could think of the PSU as a special dimmer for scrollers, rotators, and other such devices.

Originally Posted by Shawncfer

And was I right about you plug the 5pin xlr to the processor which then sends it to all the different dimmers? And what if I don't have anything plugged into a certain dimmer? Does it skip over that dimmer when giving addresses or does it still get an address in the 512 range and. Just don't patch it into my board?

Yes, you are right about it going to the processor which then decodes it and controls the dimmers. The dimmers don't know if they have anything plugged into them or not. They are a fixed thing in the sense that they are always there and are assigned a dimmer number. Yes, you can just skip over "empty" dimmers in your patch on the board.

Sounds like you are getting the hang of it. Keep the questions coming. At the risk of sounding cliche', the only bad question is the one that isn't asked.

Dave

[soundlight]

Color scrollers: you use the same signal to plug in to the Color Scroller power supply (not many scrollers take DMX directly). The power supply has a DMX in and out just like a moving light, and you set the address on each scroller.

And yes, you plug the DMX cable in to the dimmer's processor, and that sends commands to each dimmer. The dimmer doesn't care if it doesn't have anything plugged in to it, it still gets a signal from the processor if the DMX signal tells the processor to give it one.

Let's do a basic example here to clarify the scroller issue:
You have two racks of dimmers, each has 24 dimmers in it, so 48 dimmers total. Each dimmer has a light attached to it at the circuit on stage. You've put color scrollers on 8 of these lights for a particular show, so you need to control them as well. You're "patching" things "straight" or "1 to 1", so fader one means channel one means dimmer one means circuit one and fader two means channel two means dimmer two means circuit two, etc, etc. So you have to start addressing your scrollers at 49 or above, seeing as the dimmers take up channels 1-48. So the scrollers will be addresses 49-56. Here's how you connect it all up - the DMX cable runs from the console to the dimmer or to the scroller power supply first. Order of connection has no meaning in terms of the actual DMX signal. So you can either hook the cable up to the dimmer rack and then to the power supply, or to the power supply and then to the dimmer rack. After those connections are made, you have control of the dimmers but not the scrollers.

The scroller power supply is simply a device for bundling power and data - think of it like one of those fertilizer connections for a garden hose that has a little side connection for a bucket of fertilizer to be sucked in to the hose and mix with the water. The water in the garden hose is the power, and the fertilizer that you're sucking in from the bucket is the DMX. Once the water and fertilizer mix, they travel down the same hose. This is how a scroller power supply works, only with power and DMX data. So once you connect the DMX to the scroller power supply, that's like putting fertilizer in the water.

Each scroller power supply has a send and return in order to complete the circuit. You connect the power supply's send to the first scroller with a 4-pin DMX cable, then connect the first scroller to the second, then the second to the third, then the third to the fourth, etc...all the way to scroller #8 in this example. Then, you send the output of scroller 8 back to the return connection of the power supply in order to ensure problem-free operation.

With the addressing that I set up, you're going to be able to control Scroller #1 with channe 49 on the board, Scroller #2 with channel 50 on the board, etc...all the way up to Scroller #8 which will be controlled by channel 56 (unless the scrollers have more than one channel for a fan speed or color mixing or whatever, then you have to allocate more channels for them...but most just have one channel).

So the scrollers are controlled by the same console, they just require the special power supply in order to be fed power and data.

[Shawncfer]

Okay so let's pretend in order that I'm sending DMX through the dimmers first, from there it runs to a power supply, and put of the power supply comes a 4 pin xlr cable instead of 5. From there it runs into all the color scrollers and a gobo rotator first if I have one and then the moving lights and from there I plug it back into the power supply and then from there I terminate that signal if I have nothing else I need it for with a terminator thing like one of yall mentioned before. Or do I need an individual power supply for each set of items like the gobo rotators and color scrollers and others? Or can it just be one power supply for all? And if I put the power supply before the dimmer racks it won't affect it at all?
Posted via Mobile Device

[soundlight]

The power supply is only used for scrollers and certain types of gobo rotators. Moving lights take straight DMX.

If you go in to the dimmers first then to the power supply with the DMX, you then take the DMX out of the scroller power supply and that DMX signal goes to the moving lights.

Lemme draw up a diagram, back shortly with a .pdf.