DMX Signal Interferance

[Tyler]

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[CowboyDan]

Have you moved the fog machine to see if you can recreate the interference with the fog machine away from the DMX adapter?

[CowboyDan]

Copy and paste this in your browser I think that it may help you some more. Hope that it helps.


http://members3.boardhost.com/dmx512/msg/2839.html

[Footer]

I don't think he wants to control his fog from the console. Sounds like to me either a power drop in the circuit or electrical interference. First, I would try putting your fogger on a different circuit then the one it is currently on. Also, make sure everything is properly grounded. Lastly make sure that all the cables you have are shielded.

[Van]

Definatly sounds like an RF interference problem. The motor in the fog machine , if I remember correctly is an induction style frame motor, these are nortorious for creating both RF and magnetic interference. Solution. put a remote on the fog machine and move it away from you. I hope you have filters on the PC you're using as well. Haveing an active fog machine that close to a PC spells trouble, Glycerin and electronics , bad combo.

[Footer]

Originally Posted by Tyler

How do I shield the cables? I tried using the remote, but it didn't work. The next time I go in I'll try extending the remote farther. Would it be interfering with the dmx to usb unit or the xlr cables or both?

Most likely in the DMX run, not the USB.

[Van]

Originally Posted by Tyler

How do I shield the cables? I tried using the remote, but it didn't work. The next time I go in I'll try extending the remote farther. Would it be interfering with the dmx to usb unit or the xlr cables or both?

IS the usb to DMX a box ? or small dongle thingy ? Actually if either is close to the fog machine they are most likely picking up magnetic interference. As a precaution I would do a couple of things.
1. move fog machine as far away as possible.
2. Make very sure you are plugged into a completely different power source, hopefully one that is completely insulated from line flucuations. it's possible that your fog machine is creating line flucuations or harmonics that are being introduced to the pc through the power. A line conditioner should take care of that, something like a high quality UPS not just a good surge protector.

[TomyN]

Hi,

is your DMX line terminated correctly (on both ends)? Is the DMX wired correctly, using the right cables? What about the shield of the DMX cable?
Does the USB -> DMX converter have a seperate power suply or is it fully USB powered? Is it in a metall housing? Does wrapping the interface with aluminum foil change anything?

Tomy

[SHARYNF]

the fog machines could cause interference in several ways

One is the heater, usually takes quite a bit of current so it is possible that when you use the fog, it is pulling down the voltage and causing a problem with your pc-usb voltage connection to the light jockey

Van is correct in that another possibility is that the fog machine is creating magnetic interference, this could be in a wide variety of situations, is light jockey running on a notebook on the table with the fog machine on the floor, or is the fog machine on the table, next to the notebook, OR is the pc a tower and again is the fog machine next to it.

Magnetic interference could be causing the disk to create an error, or could be simply interfering with the data transmission from the pc to the Light Jockey unit.

I'd first as recommended move the fog machine away from the pc/light jockey and see what ahppens

on the power side of things I would make sure that the fog machine in on a completely different circut

If they need to be close and it is the magnetic interference then some sort of metal shield between the fog and the pc might help

Sharyn

[PhantomD]

Originally Posted by Tyler

It is a plastic dongle powered by usb only. The computer is powered on the same circuit and power strip as the fog machine.

That's a recipe for disaster - any tech who knows what he's doing shouldn't have set you up like that.

I should know, I was chasing all sorts of faults for ages - in an analogue system!!! Then we went DMX