DMX Controlled Flame Projectors

[JackPott]

Hi all,

 

Just a quick thought which spawned in my head following on from the recent post about flame projectors. I've never used them so don't know the ins and outs, but I recall a post many moons ago on here discussion the various reasons for and against using DMX for safety critical applications like moving staging and pyros.

 

Plenty of repetitions of this in the archives, and the output is usually you shouldn't use DMX because of its lack of error checking but don't see anything specific to flame projectors.

 

However, it seems that many of these flame projectors do use DMX as their trigger.

 

The only difference I can think of between a pyro and some sort of fire projector is a quick blip would be enough to trigger the pyro, however a quick blip wouldn't result in much effect at all from a flame projector.

 

So, as its logical to end a post with a question, why is it OK to use DMX to control 10m jets of fire, when it is not acceptable to use it to control a small smoke puff? What am I missing?

[Ynot]

You're quite right that this has indeed been discussed before, and I suspect your question may well spark (pun intended!) a whole new discussion with all the old arguments.

 

Cue the mods to maybe combine this with an older thread?

 

However, just because you CAN use DMX (with all the necessary dead-man's handle type precautions) doesn't mean you should in all situations.

I personally wouldn't control any safety critical effects with DMX - particularly as I suspect we have a noise problem of sorts somewhere in our distro that I've yet to trace. I'd also be cautious because with the best will in the world, when rnning through cues, it's easy to hit a channel controlling the flames/pyro for example and fire at the wrong time.

 

On the smoke side, it not only IS acceptable to control smoke machines with DMX it's almost mandatory!

;)

[JackPott]

I should clarify when I say smoke I mean a coloured smoke pyro rather than a smoke machine, of course they are almost always controlled by DMX as you say!

 

But indeed, I do not want to drag up everything that has been said before on the wider topic, my curiosity is more towards the application of DMX in a flame projector or similar, as its specifically designed to work that way by specialist effect manufacturers.

[Jivemaster]

The simple fact is that although USITT who own the DMX protocol say it should NOT be used for safety critical tasks. However several manufacturers will supply anything with DMX control to such an extent that it is becoming the defacto standard.

 

In each case it is up to the operating company to do a full safety analysis to determing whether the system is, and can be proved to be safe.

 

I am personally aware of one manufacturer in the UK producing small batches of LPG/liquid fueled flame effects who have modules to take serial, multi wire, and DMX to control their machines - developing into colours also!

[Shez]

The last time I looked at a DMX controlled flame effect, it used more than one channel, which all had to be set at particular values, a bit like a ML lamp restrike. You wouldn't want a "channel 247 @ full" to trigger it by itself!