TRIAC dimmer control spreadsheet; was Re: Controlling Holiday Lights

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

One purpose for my recent posts on this topic has simply been to provide an
antidote to the mis-information posted so that others don't waste their time.

But controlling 110/220 volt AC also needs to be done SAFELY and in compliance
with applicable building codes. Folks that might be mislead into homebrewing
sylvan's (apparently) hypothetical nonsense might also create potentially
unsafe hardware which could be disastrous -- especially with holiday lighting
which is typically installed outdoors and in a temporary fashion.

So ... *Please* be careful and know your limitations.

That said, folks that are interested in _actually_ dimming TRIACS,
back-to-back SCRs or SSRs based on them may be interested in a spreadsheet
that I created about 5 years ago.

http://www.econtrol.org/dimmers/TRIACDimmerCalcs_MFHult.pdf

This spreadsheet solves the equations that provide the numerical values to
program the delay-after-zero-crossing for a TRIAC-based dimmer either by
bit-banging with a microcontroller or other processor including a PC or using
analog techniques.

It provides tables and graphs of:

0-10vdc control signal, Vdc
DMX512 0-255 value, also sequence number for dimmer steps in dimmer curves
Fraction of AC cycle
Phase angle, degrees
Phase angle, radians
Delay after zero-crossing, milliseconds
Output voltage, Vrms
Relative luminous intensity for a typical tungsten lamp, %

Email me if you want the .xls version (a .pdf is posted).

... Marc
Marc_F_Hult
www.ECOntrol.org


On Sat, 28 Oct 2006 00:05:44 -0600, sylvan butler
<ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxxxxxxxx> wrote in message
<slrnek5spo.vse.ZsdbUse1+noZs_0610@xxxxxxxxxxxxxxx>:

>On Wed, 25 Oct 2006 02:37:15 -0400, Robert L Bass <robertbass1@xxxxxxxxxxx>
wrote:
>>> And the DMX dimmers actually control the light how?
>>
>> Most use triacs.
>
>Yup.  And the triac is controlled by a microprocessor switching the gate
>current on and off at least 120 times per second.
>
>Of course, you (Robert) are responding to a message intended for
>Marc.  :)
>
>> I understand you.  I'm fairly certain Marc does, too.
>
>I am confident he does not.
>
>> FWIW, Marc has built a DMX-512 compatible lighting controller for home use.
>
>I wonder if he created the software that actually runs in the
>microcontrollers inside each dimmer / load controller...
>
>sdb