Impact Pete Posted April 27, 2015 Share Posted April 27, 2015 I have for simple testing purposes of LED fixtures a 6 channel Transcension SDC-6 DMX controller, 1 master fader 6 channel faders, Whilst powered using it's mains supply (rather than it's 9v battery supply) the desk would not operate my 6 channel dimmer rack, I tried it on all 3 and started to assume there was an internal DMX issue on the rack although the dimmers showed they were receiving DMX. I tried the desk on a 6 channel LED fixture which worked fine so I got out my jester ml24 desk which worked the dimmers fine. I asked the Importer manufacturer Prolight about it and there response is that 'Unfortunately it looks like this is not compatible with the other – this rarely happens but in this case it has' I don't really understand this as for the last 15+ years I have used DMX I have never had this issue! Anyone shed some light? Link to comment Share on other sites More sharing options...
DrV Posted April 27, 2015 Share Posted April 27, 2015 There are a few things which might be happening. The desk.might be outputting a very short DMX packet which the fixture just ignores. The break between frames or the mark after break might not be to spec - some fixtures will check this, others might not. You mentioned the external supply - are you implying that it works on the battery? If so then the ground reference for the DMX ouptput might be shorted to the +ve rail instead of the negtative or something similar. Time to stick a scope on it to see what's really coming out of the desk. Dave Link to comment Share on other sites More sharing options...
ianknight Posted April 28, 2015 Share Posted April 28, 2015 Sadly this has been an ongoing issue with the newer version of the SDC6 - there seems to be something awry with the DMX signal such that it will work with some products but not with dimmers that adhere to the DMX standard. We've tried new PIC's that ProLight have provided but to no avail - the desk works happily with Transcension products and some LED's but others it doesn't. The original version of the SDC6 (also known as the Strand Sixer and I think Elation do a version) works quite happily with almost everything, we use a couple in hire for 6 lantern packs that use AlphaPacks or BetaPacks and they're rock solid. Link to comment Share on other sites More sharing options...
Tow Posted April 28, 2015 Share Posted April 28, 2015 If it only outputs 6 (1 to 6) channels in a packet there may be problems with some dimmers/fixtures which expect to see more. Link to comment Share on other sites More sharing options...
Brian Posted April 28, 2015 Share Posted April 28, 2015 Has anyone who knows what they are doing actually looked at the output datastream to see what the problem is? Link to comment Share on other sites More sharing options...
Impact Pete Posted April 28, 2015 Author Share Posted April 28, 2015 Good to hear (in some ways) that I'm not the only one having the issue, glad I noticed it here before sending out what tests ok with other kit as 'ok' Would be good to hear from someone who has a scope and can provide data etc Link to comment Share on other sites More sharing options...
norty303 Posted April 28, 2015 Share Posted April 28, 2015 Is this the same unit being discussed here? http://www.thomann.de/gb/stairville_ddc6_dmx_controller.htm I've been looking at this as a cheap way to control some disposable foggers on a festival site later this year - the cheaper the better. I do want to get a solution that actually works however! Hmm, this looks similar to the other version of the SDC6 I found as well... http://www.thomann.de/gb/cameo_control_6_dmx_contro_b_stock.htm Link to comment Share on other sites More sharing options...
Brian Posted April 28, 2015 Share Posted April 28, 2015 If anyone has one of these desks, and doesn't need it for a couple of weeks, I'm happy to stick my logic analyser on the output and see what's going on. Link to comment Share on other sites More sharing options...
DrV Posted April 28, 2015 Share Posted April 28, 2015 If anyone has one of these desks, and doesn't need it for a couple of weeks, I'm happy to stick my logic analyser on the output and see what's going on.Likewise. I'm near Tadworth in Surrey or Brooklands most days. Would be very interested to have a look and record some waveforms.Dave Link to comment Share on other sites More sharing options...
richardash1981 Posted April 28, 2015 Share Posted April 28, 2015 I've got a Strand Sixer and access to a digital storage scope (end of the week), but it sounds like only newer units are affected - I bought mine second hand over a year ago. I'll try and get some waveforms anyway as a reference of what works! My experience is that it works on LED PAR cans, but doesn't look at all nice, because the refresh rate is very low (~10 fps) and so fades become very jumpy unless they are very slow. But I've always got reliable control with no reliability issues. I expect you can't see this on tungsten loads because of the filament inertia. Link to comment Share on other sites More sharing options...
d_korman Posted April 29, 2015 Share Posted April 29, 2015 Just put my sdc-6 on the scope - frame length is 1.2ms and it only sends out 6 channels. channels 1-5 are at 60usec intervals but Channel 6 is spaced 140usec after channel 5. Sync break is 120usec and the following mark is 40usec. Frames are sent every 98ms, i.e. frame rate is 10.2Hz. Differential output is 4.4V when running from the mains PSU. Link to comment Share on other sites More sharing options...
Chris Beesley Posted April 29, 2015 Share Posted April 29, 2015 Hi All, I am currently looking into this issue. Pete - can you bell me on the usual Prolight number tomorrow? Link to comment Share on other sites More sharing options...
Impact Pete Posted April 30, 2015 Author Share Posted April 30, 2015 Hi All, I am currently looking into this issue. Pete - can you bell me on the usual Prolight number tomorrow? Hi Chris, I had asked Elaine at prolight she replied with 'Unfortunately it looks like this is not compatible with the other – this rarely happens but in this case it has' So I assumed that was that let me /us know if there is any additional news on it Link to comment Share on other sites More sharing options...
alistermorton Posted May 1, 2015 Share Posted May 1, 2015 Hmmm ... so someone isn't adhering to the standards? Link to comment Share on other sites More sharing options...
paulears Posted May 1, 2015 Share Posted May 1, 2015 Is this the same unit being discussed here? http://www.thomann.de/gb/stairville_ddc6_dmx_controller.htm I've been looking at this as a cheap way to control some disposable foggers on a festival site later this year - the cheaper the better. I do want to get a solution that actually works however! Hmm, this looks similar to the other version of the SDC6 I found as well... http://www.thomann.de/gb/cameo_control_6_dmx_contro_b_stock.htm I have been using some of these and the 12 way versions very satisfactorily - excellent for the money, and pretty sturdy and heavy too. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.