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David Spangler

DMX signal question

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1. Am I right when I say, in simple terms, the DMX signal is the signal being sent from the computer software that turns the lights off and on, and the DC voltage is what powers the controllers and the lights. When using a cat5 cable system, DC voltage can be injected along the line anywhere depending on the number of lights and the distance from the power supply. If that is correct how far from a dongle can the DMX signal travel when going from display to display? I thought I read 1000 feet somewhere, is that, in general, true? Or is it a lot more complicated?

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Well there is a lot in that little paragraph;

 

In our world of decorating, the DMX signal is pushed by the computer through a Dongle which brokers the communication to "tell" the fixtures (lights) to turn on/off or ?? Typically the AC/DC  power is at the light from an external source.

 

You can inject power with your DMX signal on Cat5/6. This is DC voltage. This has limitations. You need to consider amerage & voltage drop. Power can be injected at both ends if needed.

 

A pure DMX signal with the proper cabling and termination can be up to 4000ft. You are not going to get this out of CAT5/6.

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Is it Intelligent pixels or dumb RGB light that you want to do

 

DMX is rather limited in its channels if using pixels and is why E1.31 (DMX over ethernet)

 

Take a look at the ACL 101 lighting manual and also take a look here and download the presentation on what E1.31 is comapred to DMX and LOR

 

Hopefully your questions can be answered

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I will be adding more dumb rgb to existing dumb rgb. The first display is 15 channels, 5 controllers that is 50 feet from the dongle, the second which I'm adding will be 45 channels, 5 controllers which will be 50 feet the first display. I'm guessing I'll be ok. Each display will have it's own dc power supply injected at the display. I will take a look at the links you suggested.

Thank you both.

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If you find your DMX signal is too weak to reach the last element, you can put a DMX repeater at the mid-point to boost the signal.  Seasonal Entertainment sells the MultiPort Blender for $40 (enclosure and power supply not included), which acts as a 3-output repeater.

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I will be adding more dumb rgb to existing dumb rgb. The first display is 15 channels, 5 controllers that is 50 feet from the dongle, the second which I'm adding will be 45 channels, 5 controllers which will be 50 feet the first display. I'm guessing I'll be ok. Each display will have it's own dc power supply injected at the display. I will take a look at the links you suggested.

Thank you both.

At that short distance you should have no issue with signal strength.. 

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If you find your DMX signal is too weak to reach the last element, you can put a DMX repeater at the mid-point to boost the signal.  Seasonal Entertainment sells the MultiPort Blender for $40 (enclosure and power supply not included), which acts as a 3-output repeater.

 

Technically it is a 4 port splitter :).  The xSplit is available in the store now as well.

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