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Fast Chasing


intertrashional

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I am having a problem where I am trying to use my 9 tomato cage trees with LED lights to move to the sounds of a violin.  I believe this is a limitation of the controller, but the lights just sort of flicker randomly or chase and miss some channels, during the fast back and forth chases.  The same problem exists if I use incan lights.  It is a fast change back and forth so I imagine that is the problem, too short of a transition time.  I am chasing across 9 channels in .05-.1 seconds.  I have tried just chasing a "full on" and I have also tried using a "dim" and it doesnt help.  The controller works fine otherwise.  I don't know if there is anything I am doing wrong or something I could do better.  Is there a minimum amount of time the controller needs to allow lights to turn on?  I have all CTB16PC Gen 3 controllers.

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Realize that the fastest that you could trigger a TRIAC is every .008 seconds (60Hz/2). That's assuming that your sequencer sends the command at exactly the right time for one half cycle. It's a good chance that it won't be in sync with the line frequency, so at 60Hz, the TRIAC probably won't actually be turned on. At .016, the TRAIC will always turn on for a at least a half cycle but likely not for a full cycle. You'll probably see a flicker if you kept repeating this. Incandescent lights don't respond this fast. Even at .025, sometimes it will light and sometimes it won't. LED's should work fine at .025 seconds though.

Does this make sense?

One way to make it work better though is to always do a fad that last at lest .032 seconds or 2 cycles. That way you'll get the light on long enough that it won't be as noticeable.

BTW, if the output of your controller was DC, you'd be able to go down to much lower times. LED's should actually turn on and off at .008 seconds.

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If I recall correctly, the LOR program works with a time resolution of 1 centi-second, ie 0.01 sec. The program will only attempt to send commands to controllers at this time resolution. To chase across 9 channels in 0.05 sec requires each channel to turn on and then off in about 0,0055 sec, ie faster than the program's maximum time resolution.

 

Even if the program could respond at this rate, the human eye does not respond this rapidly. It can barely resolve 20 frames/sec (.05 sec between frames), hence people would not see the chase, just a dimming. (The response time of the eye is why motion pictures work and these are typically only 25 to 30 frames/sec.)

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Thank you for the detailed replies! Ernie you basically described the exact hardware limitations I was thinking about but coldnt put numbers to. Geoff thanks for the software limitations as well, I will try using less channels and see if that works. If not I will come up with another idea. Thanks for not flaming me for my terminology..."a dim"....I knew it was a fade....long day by 830pm, haha.

Edited by intertrashional
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