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DMX Splitter?


PerryH

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I have seen DMX splitters that are boxes and DMX splitters that are just a Y cable. I have used the Y cables with microphones with success but don't know if they will work as good with DMX. Anyone with experience in this willing to express their suggestions on pros & cons of each.

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No, this will not work very well with the DMX signal. You need to basically multiple the signal each time it is split. This isn't the case if you are going "through" a device but if you want to put one cable into a device and have, say, 2 cables coming out, you will need to multiple the signal again. This is the DMX splitters do...take in a signal, multiply it and send it out again. We will have a DMX splitter out in a few weeks.

The beauty behind this idea is because it is multiplied you can increase your 32 device limit. For example, if your DMX device only takes up 5 channels and you had 32 of the, you would only use 160 channels within the 512 available channels. The rest are just wasted. Now, if you had a 4 channel splitter, each one of the 4 channels will and can support up to 32 devices. So, in theory you could have 102 devices on the splitter and still be within the 512 channel limit.

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Used tons of these cheap CAT5 female/female "splitters" from monoprice without problems in my 3,800 channel display last year. Of course you need to use common sense.

The 32 device limit isn't a hard limit and is very much dependent on the load each transceiver places on the line. I had over 100 devices on a single CAT5 cable with over 200 splices, each with a 6" Tee. For more "real" data I recommend this article:

http://www.maxim-ic.com/app-notes/index.mvp/id/763

Behind the display video showing them:

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  • 2 weeks later...

dmoore wrote:

Used tons of these cheap CAT5 female/female "splitters" from monoprice without problems in my 3,800 channel display last year. Of course you need to use common sense.

The 32 device limit isn't a hard limit and is very much dependent on the load each transceiver places on the line. I had over 100 devices on a single CAT5 cable with over 200 splices, each with a 6" Tee. For more "real" data I recommend this article:

http://www.maxim-ic.com/app-notes/index.mvp/id/763

Behind the display video showing them:



Love the video(s) hadn't seen those before, thanks! Would you be willing to either paste a link to the splitter you've used, or even just part number? I want to make sure I buy the right one.

Thanks!
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medman2000 wrote:
Love the video(s) hadn't seen those before, thanks! Would you be willing to either paste a link to the splitter you've used, or even just part number? I want to make sure I buy the right one?

Sure - $.72 each at monoprice:

http://www.monoprice.com/products/product.asp?c_id=105&cp_id=10513&cs_id=1051304&p_id=7294&seq=1&format=2

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  • 4 weeks later...

Interesting idea to use those spliters. I know DMX does not like to be split that way. What was the longest run of cable before you split?

I am looking at changing my DMX lines at the theatre to cat5 cables, will have to get some of them and test the idea with my moving head and mirror scanners.

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If you picture this "electrically," it really isn't a splitter that most people need, but a T layout. The signal continues on through the top bar of the T but connects to the device by the vertical part of the T.

Placed next to a controller that only has a single RJ45 jack and with a very short CAT5 cable, the passive splitter allows the controller to "listen" to the DMX signal as it continues on down the line. The key is keeping that T cable short to minimize the impact on overall signal impedence.

When I used the term "electrically" above, that is exactly what the two side by side jacks on most controllers are, a T connection.

On the Lynx Express, Rev 5 boards, there is a 3rd RJ45, but it isn't just a T. It actually captures and re-broadcasts the signal.

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I didn't get one of those splitters. :)

It does true signal regeneration and would therefore remove the 32 device limit mentioned for a single DMX universe (though that isn't really a hard limit, just a suggested limit).

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This is a DIY site. It's not commercial site so there is nothing for sale per say.

You will need to join DIYLightAnimation.com. Post your introduction post to get your id activated. Once this is done send a PM to "RJ" asking to if he has DMX splitter PCB's available. If he does he will send you instructions on how to pay for it.

After this you can use the mouser link to purchase the parts to build the splitter.

This link shows the PCB's he has.

http://diylightanimation.com/index.php?topic=4980.0

Be patient. He's swamped like everyone this time of year.

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Jeff, you're correct. There is one input, one normal output and three regenerated outputs.

Anyone using these - keep in mind that all 4 of the output trains should be terminated if used. That's not a "law" but it is good practice.

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JonB256 wrote:

It is a kit only. One input, four regenerated outputs.


I ready on the forum over at DIYlighting that was the ver1 board. ver2 only has 3 regenerated outputs because of an issue they had with it not working all the time.

FYI....

PM sent to JR. Time to wait....

Geron
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JonB256 wrote:

Anyone using these - keep in mind that all 4 of the output trains should be terminated if used. That's not a "law" but it is good practice.

I do have two runs and before they were deployed the terminator on the last DMX board was set.
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