DMX frame rate from LOR S3

[jeffl]

I'm curious how many DMX frames are sent from LOR S3 each second. From what I have read, 44 is the magic number. So I have a few questions.

• Does the frame rate vary by DMX device type? Enttec Pro, Open RS485 or Lynx?
• Is the Enttec Pro faster than the others?
• Are fades from DMX as smooth compared to the LOR protocol?
• Does timing, "time between timings", setting in a sequence affect the frame rate in any way?

Thank you for the DMX education.

[-klb-]

I think 44 is the theoretical maximum that the protocol supports. On the other hand, most movies are only 24 frames per second. How much better refresh rate should you need than a motion picture?

[jeffl]

You have a point there. Curiosity is getting the best of me as usual.

[-klb-]

As for some of the other parts of the question, I remember one person posting that shimmer did not look as good on a native DMX universe as on the controllers.

I also thing I remember that the Gen3 controllers should have 1024 steps in their dimming curve. The only way they can access more than 256 is via LOR fade commands, or as a side effect of custom dimming curves. With DMX, they can only use 256 steps.. I'm not sure if Gen3 firmware on older hardware will do that many steps, or not.

I believe many of us use timings spaced out so far, that they would violate the minimum frame rate for DMX, and have fixtures dropping out all the time. Many of my timing grids are only as dense as the notes in the music.

[dmoore]

-klb- wrote:
As for some of the other parts of the question, I remember one person posting that shimmer did not look as good on a native DMX universe as on the controllers. 

This would completely be a result of the host software. Using the LRO protocol the shimmer is generated controller side, using DMX it is generated host side. The upside with the DMX method is that you can have more than one type of shimmer - fast, slow, strobing, etc.

-klb- wrote: I also thing I remember that the Gen3 controllers should have 1024 steps in their dimming curve.  The only way they can access more than 256 is via LOR fade commands, or as a side effect of custom dimming curves.  With DMX, they can only use 256 steps..  I'm not sure if Gen3 firmware on older hardware will do that many steps, or not.

Unless there have been major updates to the LOR protocol that I'm not aware of, you still only have 8 bits from the client application to the controller. Of course since the LOR protocol is controller side, the PIC can use those additional dimming levels for smoother fades - this would be really useful for dimming curves on 120v LED lights.

[Ken Benedict]

Unless I am way off base, there are THREE different "frame rates" being discussed here:

DMX refresh rates, which is usually a hardware thing and is around 35-44 per second. The Enttec Pro may be able to change these for slower DMX devices, but most all DMX devices can handle the typical 40 per second.

Video frame rates (-klb-), which is usually 30 per second in normal video and 24 per second for film, in the movie theatres. But it has no bearing on DMX data rates.

Step rates (sometimes called frame rates) in your LOR Sequencer, determine how fast your lights would respond to your programmed sequences. Fastest I have used is 1/20 of a second, which is much slower than the 1/40 of a second used by DMX. Even if you had your timing grid faster than 1/40 of a second, the DMX hardware would just take whatevers in the channel value at that moment that it sampled and send it out. Most people's vision cannot see faster than 1/30 of a second, so whatever you had programmed faster than that would be a visual waste. Look at cheap half-wave LED strings and you can probably see them flicker (I can). But look at full wave strings which run twice as fast (1/60 of a second) and they seem flicker free.

Dimming curves are a different matter, seperate from any of the above.

Incandescent lights are non-linear, but because our eyes are also non-linear, it looks OK when we dim them. LEDs are very linear and conflict with what we think is a brightness error; they come on bright at low percentages and don't seem to change much above 70%.

Professional stage lighting can change these dimming curves in software (or firmware) to make them match everything else.

There are plans by LOR to have custom dimming curves in Gen3 controllers to support the LED situation. The custom dimmer curves can also solve the problem of a device (like a strobe) that needs to be either fully on or fully off. Changing the curve to the channel "snaps on" whenever the channel value is 50% or greater would be a welcome solution for many LOR users. We will see how well it works on strobes, which may eliminate Dummy loads, Ghost loads, "snubbers", or the venerable Glade Deodorizer solutions to strobes firing by themselves.

[bob]

There's no hard and fast answer, really. LOR is dependent upon the vagaries of Windows for how fast things get sent out. In practice, at least on my computer, it seems to typically be in the high thirties to low forties for a raw DMX adapter (which I believe is a typical acceptable speed for DMX).

For smart adapters (ENTTEC Pro or Lynx), LOR might actually send significantly faster or significantly slower, depending on how fast intensities should be changing (LOR only sends something to a smart adapter if an intensity has changed since the last time it sent to that adapter). That's just to the adapter, though - the adapter itself should still be sending to the controllers at a normal DMX speed.

[jeffl]

I'm curious how many DMX frames are sent from LOR S3 each second. From what I have read, 44 is the magic number. So I have a few questions.

• Does the frame rate vary by DMX device type? Enttec Pro, Open RS485 or Lynx?
  
• Is the Enttec Pro faster than the others?
  
• Are fades from DMX as smooth compared to the LOR protocol?
  
• Does timing, "time between timings", setting in a sequence affect the frame rate in any way?
  

Thank you for the DMX education.

I have been able to detect the difference in the twinkle effect between the LOR protocol and DMX but as far as fading I'm not sure. What are the fading characteristic between LOR and DMX?

How many steps does LOR S3 support when sending a fade from 1-100% using DMX. Is it 100 or 256?

Thanks