I have 2 LED fixtures that don't have a dimmer channel. I stumbled across the web page linked below and my mind fell in love with this idea. Would this be something that could be possible to do?
https://secure.chamsys.co.uk/forum/viewtopic.php?t=17
Thanks,
Daniel
Virtual Dimmer Channel
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Viktor Nova
The way that all LEDs (whether they have a DMX dimming channel or not) do any sort of dimming at all, is through PWM (pulse width modulation), since you can't just decrease the power to an LED, or it will burn out
In non-technical english, this means "strobing the LED on and off REALLY fast so that it looks like it's getting dimmer to the human eye". I have never tried to make a virtual strobing effect in QLC+, but it should be pretty easy -- although I'm not sure if the resolution of DMX is high enough to produce a true fading effect. Would be interesting to know!
In order to 'fade' from bright to dim, your function would need to gradually increase the amount of time the LED is off and/or decrease the amount of time it's on..does that make sense? =D
Edit: after reading the other responses and re-reading the OP, I believe I misunderstood the question. Your LED fixtures have faders, just no master fader..correct?
In non-technical english, this means "strobing the LED on and off REALLY fast so that it looks like it's getting dimmer to the human eye". I have never tried to make a virtual strobing effect in QLC+, but it should be pretty easy -- although I'm not sure if the resolution of DMX is high enough to produce a true fading effect. Would be interesting to know!
In order to 'fade' from bright to dim, your function would need to gradually increase the amount of time the LED is off and/or decrease the amount of time it's on..does that make sense? =D
Edit: after reading the other responses and re-reading the OP, I believe I misunderstood the question. Your LED fixtures have faders, just no master fader..correct?
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Daniel Nyström
A virtual dimmer channel is nothing but an extra DMX channel not available on the fixture but act within the software as a submaster of the R, G and B channel together. Very useful for mixing color functions and strobe/dimmer functions while still keeping the separated. Virtual dimmer channels are available on most commercial lighting consoles.
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Shikhir Arora
Daniel - What you are saying exists I think in Virtual Console mode on the left side. Run a project from there and you get essentially what you just said when you modify the sidebar.
For example in my project (fairly simple), the bar, when playing my Cuelists triggered by Audio Triggers for two movable lights and 4 standard RGB LED fixtures, lowers (dims) everything.
Haven't looked into it much, might just be because my setup is fairly simple and I defined my fixtures, but that looks like what you're describing.
For example in my project (fairly simple), the bar, when playing my Cuelists triggered by Audio Triggers for two movable lights and 4 standard RGB LED fixtures, lowers (dims) everything.
Haven't looked into it much, might just be because my setup is fairly simple and I defined my fixtures, but that looks like what you're describing.
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Matthew Marks
Viktor, the reason for PWM is not to prevent burning out of LEDs (they will work quite happily at any current at or below maximum) but to increase efficiency (and correspondingly reduce heat dissipation) of the controller, as it wastes least power when fully on or fully off.
You are right to suggest that PWM will not work directly with DMX as the frame rate, in the order of 50Hz, is far too low.
You are right to suggest that PWM will not work directly with DMX as the frame rate, in the order of 50Hz, is far too low.
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Charles
Virtual Dimmers don't need to do PWM, they are just submasters/macros defined at the fixture level.
For instance on a RGB LED Parcan with Red, Green, Blue channels but no master dimmer you could create a Virtual Master Dimmer that multiplied the RGB channels. So at 255 the multiplier would be 1.0 (full intensity) at 128 would be 0.5 (half power) and that multiplier is applied to the RGB channels to modify their final DMX value.
Where this is very useful is fixtures like the Abstract Twister. This has a gobo/colour channel and a rotation channel but no intensity channel at all so doesn't react to the Grand Master. However if both channels go to 0 after a few seconds the lamp shuts down and the fixture sleeps. So if we could create a Virtual Master Dimmer that overode both channels with '0' when it was set in the range 0-15 but did nothing in the range 16-255 then these fixtures would react to the Grand Master.
For instance on a RGB LED Parcan with Red, Green, Blue channels but no master dimmer you could create a Virtual Master Dimmer that multiplied the RGB channels. So at 255 the multiplier would be 1.0 (full intensity) at 128 would be 0.5 (half power) and that multiplier is applied to the RGB channels to modify their final DMX value.
Where this is very useful is fixtures like the Abstract Twister. This has a gobo/colour channel and a rotation channel but no intensity channel at all so doesn't react to the Grand Master. However if both channels go to 0 after a few seconds the lamp shuts down and the fixture sleeps. So if we could create a Virtual Master Dimmer that overode both channels with '0' when it was set in the range 0-15 but did nothing in the range 16-255 then these fixtures would react to the Grand Master.