Enttec USB Pro Problems and Arcnet Workaround

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Buddha67
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Joined: Mon Feb 20, 2023 6:56 pm
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Hi and Greetings All,

I'm using:
Ubuntu 22.04
Enttec USB Pro (an older model)
QLC+ 4.12.6

With the Enttec USB Pro, lights are flickering and unstable with QLC+. When I use other DMX control systems (light board, OLA) they are stable.

I have tired replacing cables, using a USB hub, and any other solution I could think of. Flickering in unchanged.

I installed OLA on the same system, and the lights/device seems very stable when using OLA. My next step was to configure QLC+ to use Arcnet to communicate with OLA (a workaround suggested http://www.qlcplus.org/forum/viewtopic.php?t=8165 and elsewhere)

However, as soon as I start QLC+ it does a probe or something and disrupts the OLA communication with the device - at which point I can no longer control the lights with OLA so my workaround fails.

I would appreciate if anyone has a suggestion for:

- How to solve the original flickering issues using the Enttec USB Pro with QLC+

- How I can prevent QLC+ from disrupting the the connection with OLA to help enable my workaround.

Many thanks in advance,

David
Buddha67
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Joined: Mon Feb 20, 2023 6:56 pm
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Ok, as an update to my own post. I think the reason OLA stops working when QLC+ starts has something to do with the libftdi library, and the fact that when QLC+ calls it on startup, the /dev/ttyUSB device disappears.

If there was a workaround for that, it would be helpful.

Many thanks,

David
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mcallegari
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two comments:
1- do you know it is possible to adjust the output frequency of a DMX USB device?
2- to disable a plugin, just move the plugin file away from the QLC+ plugins folder which on Linux is:

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/usr/lib/x86_64-linux-gnu/qt5/plugins/qlcplus
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GGGss
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Real Name: Fredje Gallon

Flickering with an Enttec USB pro - unless there is an interfering fixture (messing up the DMX signal chain) - could indeed need an adjusted timing.
Comming out of the box (with the firmware) these are the DMX timings applies. (You can change the Enttec applied timing with the DMXPro tool)

Code: Select all

				02/02/2022	04/02/2022		07/02/2022	18/03/2022
				GMa on PC	City Theatrical DMXcat	Enttec Pro MK2	Artnet6UN
Break (μs)			178		192			102		87
MAB (μs)			44		60			13		7
MTBS Interslot (μs)		0		4			0		0
MtBB (μs)			10500		2300			32		8
slots				512		512
Fps (Hz)			30		37			44		44.1
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Buddha67
Posts: 3
Joined: Mon Feb 20, 2023 6:56 pm
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Thank you for the prompt response!

I checked the DMX timings, and didn't see anything obvious. I tried adjusting the FPS, and did not see any change to the flickering.

I didn't mention before, but the lights do not flicker when I use QLC+ on a Mac. The Mac has other issues (occasionally disconnects from the USB Prom and less occasionally crashes), however.

Given the the USB Pro does not flicker with the Mac, and also with OLA on Ubuntu 22.04, my assumption is that the problem is not with USB Pro/DMX.

Thank you for the information about how to disable the USB Serial plugin. This allowed me to proceed with the "QLC+ -> Arcnet/OLA -> USB Pro" workaround. This proved to be very stable in a show last night so I am going to proceed with that for now.

If OLA uses the same libftdi library as QLC+ (I think it does?), comparing the code may reveal optimizations helpful toward resolving the issue. I appreciate the work you all have put into QLC+; I am hoping I have time to give this a go.

Many thanks,

David
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