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How to change the DMX frame rate to run hqpower heads.

Posted: 07 Mar 2007, 14:47
by Mystic
Hello,

I have a quite technical problem i cannot easily fix by myself. I have a pearl 2004 (on a pearl 2000 borris 1 hardware) and some velleman/HQ Power moving heads. The moving heads response is jerky (channels are unstable and values changes), however while using them with a chamsys magicQ console it works fine. So I tried to analyse the DMX signal on an oscilloscope to find out what was the difference. I found out that the chamsys generates dmx frames with a little idle time after each channel packet information (6us, so the overall packet is 50us instead of 44us). The avo have no idle time after each packet. It seems that my moving head needs this extra timing to process data corectly (slow brain ? :) ).

So the question is : how can i change the behaviour of my loved pearl desk to produce a dmx frame that contains those little idle times after each packet ? Is there a configuration option (didn't find it) or a special hack ? Or maybe, could people at avo release a new version (custom?) that fix this ? I really need to be able to control those moving head with the avo...


Thanks for your help.


ps: if anyone needs more information on the subject, feel free to ask me.

Posted: 07 Mar 2007, 22:04
by niclights
The only DMX timing value I know of in the Pearl is User Settings option 13. Does reducing this help?

Posted: 07 Mar 2007, 23:33
by Mystic
nope... nice try :)

Posted: 08 Mar 2007, 15:27
by kikixxx
demande à velleman qu'ils update'nt leur soft interne?
c'est quand même une boîte de bricoleur en électro, ça devrait être jouable!

Posted: 08 Mar 2007, 16:28
by Mystic
Nope velleman won't do it, they don't even have a proper manual for this moving head... they are just "box shippers", the stuff is built in china and they ship it to europe to sell it....

Posted: 14 Mar 2007, 12:37
by Tawnyn
had the same problems with a client last year..... dont buy Velleman :P

Posted: 14 Mar 2007, 13:00
by Mystic
dont buy Velleman :)

mmm was a kind of a gift... may be i should be more careful 'bout my friends ;)

but, back on the serious side : is there any answer from someone at avo ? i'm quite sure it is possible to patch the console code for this as it does not break the DMX spec...

Posted: 14 Mar 2007, 13:12
by Tawnyn
Mystic wrote:
dont buy Velleman :)

mmm was a kind of a gift... may be i should be more careful 'bout my friends ;)

but, back on the serious side : is there any answer from someone at avo ? i'm quite sure it is possible to patch the console code for this as it does not break the DMX spec...


i am afraid not, we asked Avo programming people how we could solve the problem and in the end we had to put a "budget" ranged desk to do the show....

maybe they did find a solution since its been almost a year :D

Posted: 15 Mar 2007, 15:45
by CoenCo
I've had succes solving similar problems using a DMX-ethernet-DMX converter. In this Instance I used an ELC DMXlan node4. It converts DMX to ethernet and back (4in, 4out). It allows you to set the DMX-refresh rate for each output independently. Might be a bit pricey for this situation (if you use velleman for moving heads, you probably don't have 2000 eur to spend on a converter) but it has some other nice features as well, that might be worth the price. i.e. DMX merger/splitter/softpatch/remotecontrol with Wifi+PDA/dmx-artnet to input to an offline visualiser, etc.