help. 4.12.0 open enttec output frequency

Ask a question about the usage of QLC+ with the Linux operating system
Post Reply
giacomo
Posts: 553
Joined: Tue May 26, 2015 6:17 pm
Real Name:

linux 64 qlcplus 4.12.0. open enttec

the default output frequency is 44 Hz and it wasn't working properly on my setup, I was missing a big part of the fixtures output, so I've lowered it to 30 Hz.
Is it a good setting?
thanks for any suggestion
User avatar
mcallegari
Posts: 4711
Joined: Sun Apr 12, 2015 9:09 am
Location: Italy
Real Name: Massimo Callegari
Contact:

Have a look at this
viewtopic.php?f=17&t=12499

I had to lower it too, but in my case it worked at 40Hz (on Windows), and I have a clone. On Linux it was working good at 44Hz.
Do you have the original Enttec product or a clone as well ?

For the record, 30Hz is the frequency used by 4.11.2 and previous versions.
giacomo
Posts: 553
Joined: Tue May 26, 2015 6:17 pm
Real Name:

it's the real one. I've lowered to 30Hz because I was remembering a value like this in previous qlcplus.
if it's correct I'll keep it, we had rehearsals all the afternoon and it seems to work fine, what would I gain if the frequency is 40?
User avatar
mcallegari
Posts: 4711
Joined: Sun Apr 12, 2015 9:09 am
Location: Italy
Real Name: Massimo Callegari
Contact:

Smoother fades.
Think about it. If you fade from 0 to 255 in one second, 30Hz will output 30 values, while 40Hz will output 40 values
giacomo
Posts: 553
Joined: Tue May 26, 2015 6:17 pm
Real Name:

ok!
first show with 4.12.0 and everything went fine.
I didn't dare to try 40 Hz because there wasn't any spare time for testing but
thanks for the confirmation and explanation, this morning I went a bit worried.
Btw, in this venue I've found 2 technicians that knew qlcplus :)
User avatar
GGGss
Posts: 3052
Joined: Mon Sep 12, 2016 7:15 pm
Location: Belgium
Real Name: Fredje Gallon

giacomo wrote: Wed Nov 14, 2018 12:42 am Btw, in this venue I've found 2 technicians that knew qlcplus :)
Allright !! Now you have 2 less criticisms about your performance ...

PS: Maybe We (I) should spend some time explaining timing, tackt frequence and dimmer curves ... only ... it will need 2-3 nights documenting it and all of a sudden you realise how much effort Massimo put inside this project
All electric machines work on smoke... when the smoke escapes... they don't work anymore
giacomo
Posts: 553
Joined: Tue May 26, 2015 6:17 pm
Real Name:

hi Fredie,

yesterday I didn't have time to write longer about my concerns but now I've a couple of questions for you.

1) Especially in case of conventional lights, will we notice a difference between 30 vs 40 Hz refresh rate?
I suppose that we won't see any difference when using incandescent bulbs.

2) In general, is it recommended to use the maximum refresh rate or is it safer to set a refresh rate lower than the maximum capability?

thanks
User avatar
GGGss
Posts: 3052
Joined: Mon Sep 12, 2016 7:15 pm
Location: Belgium
Real Name: Fredje Gallon

Difference between 30 and 40Hz ...with incandescent light ... nope you wont see a diff.
But many individual lights doing a dim over a short time can cause some interference - ergo 'it doesn't look tidy'

With led I'd be a bit more careful.
Say we DMX is fed at a 10Hz rate. = 10 cylces per second.
Say we do a dim from 0-255 in 1 second: that means that the bus would be fed with 0, 26, 51, 77, 102, 128, 153, 179, 204, 230 and 255 (this with a linear dimming curve)
0 -> 26 will be noticeable; as expected the light goes on
and the range from 100 - 180 will be noticeable also - you will see clear steps
The human eye can distinguish light pulses up to 13Hz. Once above they are percieved as being on ... unless you move your head you see a flicker

2) the max defined refresh rate is 44Hz as per DMX-512-A. If you only have 1 channel at address 1 to send you'd could use a refresh rate of 0.1Hz (theoretical because there is overhead starting a transmission) Say you only have 1 channel at address 512 then you'd need a vast higher refresh rate.
All electric machines work on smoke... when the smoke escapes... they don't work anymore
giacomo
Posts: 553
Joined: Tue May 26, 2015 6:17 pm
Real Name:

today I had the opportunity to try 40 Hz and randomly it was blinking to black
so I've lowered the frequency to 33 Hz and it seems ok,
tomorrow I'll have more time to "watch" it but I believe that 30 is a safe value.
I'm posting this if other people have the same issue and they don't know what frequency they should set.
User avatar
mcallegari
Posts: 4711
Joined: Sun Apr 12, 2015 9:09 am
Location: Italy
Real Name: Massimo Callegari
Contact:

Thanks for sharing the information Giacomo.
You should also state that you use Linux though, cause on Windows/macOS the behavior might be different.

In any case it's unbelievable there are so many DMX products (Eurolite included) that do not respect the DMX timings (44 Hz)
And the "original" products cost a fortune compared to clones....unbelievable.
giacomo
Posts: 553
Joined: Tue May 26, 2015 6:17 pm
Real Name:

just a report for the developers if it can provide any interesting information.

_refresh rate 40 Hz_
yesterday we were focusing with the web interface enabled and it was blinking to black slowly but continuously even with one light on.
today I tried 40 Hz during the rehearsals - without the web interface enabled - and it worked almost good: I've noticed few blinking to black when I was moving manually knobs or slider.
(not a big show: scenes with 10>30 channels and few loop-backs)

_refresh rate 33 Hz_
I haven't noticed any misbehavior.
Post Reply