Q Light Controller+

Hello Community,

I am a beginner in using QLC+ (version 4.12.6).
I have a Eurolite USB DMX512 Pro Cable Interface connected to 6 LED spots and a Fun generation Minispider 8x3W. I was able to learn QLC well thanks to the help of How to videos. But I have big problems with the MiniSpider. While all the spots can be controlled according to the manual, the MiniSpider has a superimposed flicker or unwanted movements of the two bars. In stand-alone mode, the Spider is fine, so I suspect that the DMX control is defective. The fixture I have used both from QLC, but also completely recreated again with the same result.

Is there any experience with the USB adapter? Does anyone use it successfully?
It is released by QLC, the protocol is also set to RX/TX.
Which output repetition frequency must be set? There is nothing in the manual.
I hope you can help me. I have also asked the support of Fun Generation (Thomann) (answer pending).

Thank you and best regards Carsten

I checked the manuals for the Eurolite USB DMX512 Pro and the Eurolite USB DMX512 Pro Cable and noticed some differences.
For the PRO you need to go to the Eurolite site to download drivers but for the PRO CABLE you need to go to the FTDI site.
I therefor assume that the PRO Cable uses a different chip than the other Eurolite PRO models do (or has another manufacturer then the other models).

I noticed that you correctly followed the instruction on the QLC help for the DMX USB input/output plugin: Eurolite USB-DMX512 Pro devices must be forced to the "Pro RX/TX" mode to operate correctly.

As the PRO Cable seems to be different I suggest you try if it will work with "Open RX: Generic FTDI devices receive mode".

On my Sweetwater Dongle that also uses a FTDI Chip (almost all those Cable Dongles use this Cihp) this works fine.

If that doesn't work it might be a cabling issue.
In the Midispider Manual you can even find the following warning:
NOTICE! Possible data transmission errors.
For error-free operation make use of dedicated DMX cables and do not use ordinary microphone cables.

In general you could put this warning in every Manual of any DMX fixture (just because DMX and XLR cables have different impedances) but most fixtures are not that critical, they work fine on both types of cable.

What you can do is experiment with your chaining : put your Minispider First (before the Led Spots), in the Middle and Last (after the Led Spots).

In general you also should end your DMX chain with a terminator. In practice most fixtures still work fine if you don't use that terminator .
just try if it makes the difference.

Thanks for the welcome help and quick replies.
I forgot to mention some things which I had already tried and which you now offer as a solution:
I have
- loaded the latest FTDI drivers
- tried different addresses and address distances
- a terminator and also dedicated DMX cables in use

Different positions in the DMX chain brought unfortunately also no improvements.

On different output frequencies the Minispider reacts differently (more or less) to the described errors. The best result I still have with 60 Hz.

I fear a defect in the device.
I just wanted to exclude that it could be due to QLC or the USB Pro Cable Adapter and I just chose a wrong setting.
I have basic technical understanding but I am new to QLC.

Thank you and best regards Carsten

MichelSliepenbeek wrote: ↑Thu Feb 23, 2023 6:22 pm NOTICE! Possible data transmission errors.
For error-free operation make use of dedicated DMX cables and do not use ordinary microphone cables.

This is really overrated ... don't mention this Michel - 80% of the industry uses mic cables throughout.
Once a cable run exceeds 80m, I start using cable with 120 Ohm impedance and a terminator to commit reflections in the cable.

@Carsten: a frequency of 60Hz is out of band for DMX. Try 20-30Hz. You can go to a max. of 44Hz to be DMX compliant.
And it might not be the spider that is defective, but your other fixtures which superimpose a signal disturbing the DMX train.
What if you only use the spider? Still problems? Try to isolate as much as possible and KISS (keep it simple stupid of stupid simple).

thank you very much for your answer.

After consultation with Thomann, I will send the MiniSpider back for inspection or repair. I think I have exhausted all possibilities to eliminate possible errors. Even a reduced output frequency to 30 Hz did not help.

However, should the repair also bring nothing, the troubleshooting begins again