Strange Acme Puma DMX behaviour

[DJ Jules]

I've got a pair of Acme Puma's (generic 250w halogen moonflowers) that I've been using for some time now with a CA-8 controller to blank them and control the gobo for first dances, etc.

I've been trying to switch to full DMX for some time and I played with using a Soundlab DMX controller with them some time ago and I'm now using a USB DMX dongle.

With both DMX controllers I've noticed some strange behaviour. They pick up on the DMX signal, but they intermittently "twitch" (I'm struggling to find a better way of describing it). They'll continuously show the required gobo and then flick back to closed and then flick back to the gobo and then flick back to closed again. There's no pattern to the timing (it's apparently random) and it effects all of the control channels (strobe/gobo shake, gobo and mirror speed) when they're on anything other than DMX 0.

If I use the CA-8 I can set the gobo and it'll hold steady so it's not the motors themselves, it's got to be something to do with the control board and how it's interpreting the DMX signals.

The DMX dongle (and the aforementioned Soundlab controller) both work fine with other fixtures. I've also used them with and without terminators on both long and short cable runs with the same issue.

Has anyone come across this before? Does anyone have any suggestions for diagnosing/fixing this issue?

Thanks,

Julian

[katman]

Just a thought.... is there a temporary glitch in the DMX data stream ?

What do the fixtures do if you remove the DMX signal, do they go to closed.

Early DMX equipment depended on a continuous DMX stream, if it stopped the lights went out, later equipment will hold the last recieved setting if the stream is lost.

If it goes off when you disconnect the signal see if there is a configurable option for what the fixtures do when signal is lost.

[Kernow]

It's also worth noting that the Soundlab controllers are wired in reverse polarity (as are their lights ! ;)) to most others. You will need to put a polarity changer http://www.ebay.co.uk/itm/XLR-PHASE-REVERSE-ADAPTOR-MALE-FEMALE-/320730125375?pt=UK_Sound_Vision_Other&hash=item4aad01543f in the DMX line to use them with Acme lights.
I know this from having used Colourscans on the same daisy chain as an Impossibled.

[Jiggles]

Another problem can be if there is a break in the 0v line of the DMX leaving the line floating that can cause all sorts of problems in cheaper DMX devices.

[SoundONE]

Are you using a termination plug on the end, could be the problem.

[DJ Jules]

Just a thought.... is there a temporary glitch in the DMX data stream ?

That's what I wondered about, but I've got multiple lights on the chain and none of the others seem to register a break in the signal (scanners that are slowly panning across do so smoothly).


What do the fixtures do if you remove the DMX signal, do they go to closed.

The Puma's stay on the last DMX instruction when they lose the signal (I've pulled the cable out while they're live a few times).


If it goes off when you disconnect the signal see if there is a configurable option for what the fixtures do when signal is lost.

There's not a lot of configuration on these. Master/Slave and DMX address!


It's also worth noting that the Soundlab controllers are wired in reverse polarity (as are their lights ! ;)) to most others.

Good point, but the soundlab controller had a polarity switch on the back of it (which I discovered once by accident at a Gig where I couldn't get the lights to respond!) The DMX dongle doesn't though and the rest of the lights seem happy enough. It's a good point though that they work master/slave just fine and this behaviour is similar to what I observed when I had the polarity set wrong on the Soundlab controller. I wonder if it's possible that the Puma's are wired in reverse??


Another problem can be if there is a break in the 0v line of the DMX leaving the line floating that can cause all sorts of problems in cheaper DMX devices.

If there's a break in 0v, it's inside the fixtures as other devices in the chain are happy enough.


Are you using a termination plug on the end, could be the problem.

Yup, as per the original post.

I'm going to check the wiring in the fixtures to make sure that 0v is getting through and none of the cables have been switched internally by accident. If that doesn't show anything, I might flip the cables in one of the fixtures to see if it is a polarity issue.

Thanks for all the suggestions - keep them coming!

Julian

[SoundONE]

Someone else had a similar problem turned out it was a cheap usb dmx, he replaced it problem fixed, appears the circuitry doesn't like noise or has very poor filtering in the puma and so a good controler is required: heres part of this other chaps findings, if you could borrow or hire another controller be worth a go.

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No it's not cables problem. It's not problem of FS. I find a solution after about 10 days without sleep ;)

Before posting I tried connect on few different cables, only Pumas, with others, address changing, lot of time spent on trying to configure FS, etc... and nothing.

After meny tries and many hours spent for reading forum I figure this is problem with poor USB to DMX converter from AVT, and THATS IT!.

Today I bought Enttec USB PRO and after small configuration it's work great. I think problem was in clock in old converter.

So problem IS SOLVED. Yupi
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[DJ Jules]

Someone else had a similar problem turned out it was a cheap usb dmx, he replaced it problem fixed, appears the circuitry doesn't like noise or has very poor filtering in the puma and so a good controler is required: heres part of this other chaps findings, if you could borrow or hire another controller be worth a go.

It did occur to me that it could be this, the Soundlab controller wasn't exactly the Rolls Royce of DMX gear ;)

I'm inclined to replace the lights with something 8kg a side lighter with an LED light source rather than shell out for a new DMX cable (as it seems to do the job for the rest of the fixtures). :D

I'll have a play with polarity and connections first, and then think about replacing them - unfortunately I don't know anyone else with a decent DMX controller. Thanks for the info though.

Julian

[DJ Jules]

Quick update on this. Last night I pulled out a couple of 250w Barrel and Mirror scans that I haven't used in a while and added them to the chain. I've used these previously on the Soundlab DMX controller without any trouble, but on this controller they respond properly for a short while, and then reset!!

Time to invest in a decent USB to DMX dongle - if anyone has one for sale, let me know?

Julian