How many times can you split a DMX signal?

[DJ Higgumz]

I have an idea to make a 30ft dmx loom where every 3 ft I have an xlr female splitted out of it. that way I can cut 30 minutes out of setup time by having a pre-wired truss, and having the ability to size my truss and use lights accordingly. so my question is, electronically, can I split my dmx signal 9 times? is it the same effect as daisy chaining?

[BillESC]

Yes it is the same as daisy chaining.

[allensmusic]

Yes it is the same as daisy chaining.

Interesting. for some reason I thought it was bad to split DMX that much.
This sounds like a good way to simplify setups

[Synaxis]

Interesting. for some reason I thought it was bad to split DMX that much.
This sounds like a good way to simplify setups

Same. I was told the only proper way to split DMX is with a DMX Splitter Box, Such as the Chauvet Data Stream 4. I was under the impression that you can't just split a DMX cable into two.

[allensmusic]

so what about this?

"Splitting DMX cables
Simply making a 'Y' connector out of three XLR connectors is a BIG no-no. Depending on the quality of the cable you use and the length of each leg of the "Y" you will likely have some of the DMX signal reflect back down to the junction and out the other leg, resulting in what can best be described as schizophrenia by your DMX devices. They will start behaving in extremely unpredictable ways due to the "leak" of the signal from one leg to the other.

If you need to split a DMX signal (and it's a very common need) the right way to do it is with a device known as an optical splitter. This is a device that you plug a single DMX cable into and it may have 2, 4, or many more DMX outputs that each mirror the signal on the input line. Each of the outputs is electrically isolated from the others using optical isolators which prevent reflections from one leg impacting any of the other legs. Examples of DMX optical splitters can be found here, here, and here among others.

One nice feature of some DMX splitters is that they support both 3-pin and 5-pin XLR connectors, meaning that they can be used not only as splitters but converters as well."


http://bruce.pennypacker.org/2009/12/04/dmx-512-primer-an-end-users-perspective/

[ReelDiel]

^^^^thats the right way to do it!!!!!

[DJzrule]

The technical reason that parallel wiring INSIDE of a fixture doesn't cause issues is because the split is so small and the monitoring (receiving) circuit inside is so sensitive, it doesn't put a large load on the cable as say 2 long-ass lengths of cables split would. It's just a small 1" or 2" jumper from XLR to XLR.

http://www.controlbooth.com/threads/diy-dmx-splitter.23863/


Splitting

Never split a DMX signal with a "wye" cable. Use a splitter device that buffers each line separately or daisy chain from device to device.

The problem with splitting the signal with a wye cable is that the signal going up one leg of the wye is reflected back down and corrupts the signal going down the other leg. The longer the legs of the wye, the worse the problem. A wye where each leg is 10 feet may work fine but may fail if the legs are increased to 100 feet. A lot has to do with the quality of the cable, the strength of the signal at the wye point, and your relationship with God.

If you must split the signal, and you don't have a buffered splitter, do it as close to the source as possible, i.e. at the console. If you have an isolator available, place the wye at the output of the isolator. If you have two isolators available, place the wye at the input to the two isolators (which is like making your own splitter).



http://www.dfd.com/primer.html

[allensmusic]

The technical reason that parallel wiring INSIDE of a fixture doesn't cause issues is because the split is so small and the monitoring (receiving) circuit inside is so sensitive, it doesn't put a large load on the cable as say 2 long-ass lengths of cables split would. It's just a small 1" or 2" jumper from XLR to XLR.

http://www.controlbooth.com/threads/diy-dmx-splitter.23863/



http://www.dfd.com/primer.html



okay, and the custom cord the OP is talking about would have short pigtails to connect. so it can be done as long as the pigtail is very short?

[DJzrule]

okay, and the custom cord the OP is talking about would have short pigtails to connect. so it can be done as long as the pigtail is very short?

It can be, but its technically not the proper way. IMO, it'd be easier to take short XLR jumpers, zip tie them, and properly connect the DMX fixtures.

[P25CT]

Here's what I was thinking of doing maybe it will help.

So I have several sticks of F34. I was going to prewire each stick with dmx and power for quick connect.

So let's use an 9' stick for ease of explanations from left of stick to right: Several short cables. First cable comes in and terminates at 3 feet. Another one picks up where that left off and goes another 3'. Same thing and again for the third. It then terminates on other side. So you have three spots for a fixture. If you don't use a spot just connect the two cables together. If you tie one stick to another just plug in the next stick. I'm tired and I know I'm not explaining this well but it would work pretty well. Power cables same thing. This all is better with WiFly hubs. ADJ has a hub that's a WiFly rx and a multi port hub in one. I use one as a center hub for a 4 way cross. Works great!

Hope I didn't butcher that too much.


Sent from my iPhone using Tapatalk (http://tapatalk.com/m?id=1)

[DJzrule]

Here's what I was thinking of doing maybe it will help.

So I have several sticks of F34. I was going to prewire each stick with dmx and power for quick connect.

So let's use an 9' stick for ease of explanations from left of stick to right: Several short cables. First cable comes in and terminates at 3 feet. Another one picks up where that left off and goes another 3'. Same thing and again for the third. It then terminates on other side. So you have three spots for a fixture. If you don't use a spot just connect the two cables together. If you tie one stick to another just plug in the next stick. I'm tired and I know I'm not explaining this well but it would work pretty well. Power cables same thing. This all is better with WiFly hubs. ADJ has a hub that's a WiFly rx and a multi port hub in one. I use one as a center hub for a 4 way cross. Works great!

Hope I didn't butcher that too much.


Sent from my iPhone using Tapatalk (http://tapatalk.com/m?id=1)

That's what I was saying. Make a snake with power and XLR with short jumper cables, that way you can connect them into each other (power you wouldn't have to if you were using individual IEC + MOXC [Multiple Outlet Extension Cord] cable) if you need to skip a spot where you don't need a light.

[BillESC]

Having re-read the OP's post, I need to change my answer.

He needs to provide a male and female XLR at each break so it fact the daisy chain can continue. If he doesn't have a fixture at one of the breaks, he can plug the male and female together to provide continuity.

[DJ Higgumz]

I've already done that, the only difference is I don't have extra fixture plugins for flexibility, just for where I mount my fixtures. I guess there are reasons things arent done already