Enttec OpenDMX + QLC + Showtec LED bars = weird behaviour

[kentabenno]

Hi,

I'm a newbie when it comes to lighting and for the start I got myself a relatively simple setup containing a OpenDMX USB interface, three Showtex Pulse Pixel Bars (connected in series), controlled of course by QLC+ (4.12.1). The chain is terminated by a 110 Ohm resistor terminator.

The LED bars are set to Pixel Control Mode (64 channels per fixture).

Basically the setup works but there are two major problems that I can not get under control:

- in this example only the middle fixture should flash up blue. while turning off, both of the other fixtures flash uncontrollably in random colors:


- in this example all three fixtures should flash up simultaneously. but the last fixture in the chain always lags behind half a second or so. furthermore, it turns off by flashing partly or fully, randomly.


I have already googled a lot but did not find any information on these particular problems. I have already tried to lower the frequency of the interface (down to 30Hz), which changes something (the patterns of flickering change), but does not resolve the problem.

Now the question: Are my fixtures broken? Should I try another DMX interface (some people have recommended trying Artnet instead of USB)? Or is it maybe a configuaration problem in QLC? I am completely startled, restarting the system, changing the cabeling, trying other power outlets, nothing worked.

Thanks for any help!

[GGGss]

In the last video - the third fixture - the 2-3 lower pixels go out quite late...
Or the signal to them is late or the fixture interprets them as being late.

Since you are already using half an universe (and timing issues mostly are noticed far down the universe) I guess your computer in combination with the OpenDMX could be the source of troubles?
Since the OpenDMX is not 'intelligent' you are using your processor to get the DMX-signal-train timing right.
I have 6 fixtures with each 16 pixel in pixel control mode ... no issues with my EnTtec PRO MKII.

USB vs ArtNet - If the interface is intelligent - no problems with USB
Artnet creates an installation overhead (switches, network config, ...) so if not explicitly needed why should you.