RE: Re: [Development] Lights functions required

["Keith Doxey" <ukha@xxxxxxx>]

Here I go, answering many questions in one go.

Channels Per Dimmer Pack/Packs Per Room...
8 channels per pack, possibly 2x4 channel boards each with one PIC per
board. That allows a 4 channel pack to be built and also makes the PCB
cheaper. Granted you would need 2 PCB's but you are buying more so the
price
per board comes down. Also limits failure.

Channel Assignment.
Some form of Dimmer/Address mapping. Lutron assign dimmers to channels.
This
allows several dimmers to have the same identity so you can handle a 20A
load as 4x5A.

Dimming Curve/Dipless Crossfade....
I dont believe anyone would notice the difference unless it was pointed out
to them. For dipless fading my idea is this. If the level is 0 to 100 and
you have 2 channels that require to do the following
A 25 > 75
B 100 > 0
with a fade time of 10 seconds you need to do the following. Increase A by
50 steps and decrease B by 100 steps. You have 10 seconds to complete this
so that gives A needing to step 50 times in 10 second = increase 1 step
every 200mS, B needing to step 100 times in 10 seconds = decrease 1 step
every 100mS. The only calculation needed it to work out how many steps in
the time period.

Fault detection.
Subject to having spare pins available on the PIC you can detect
No Output - fuse or relay blown
Continuous Output - Triac blown
No Load - All lamps disconnected (NOT INDIVIDUAL BULBS unless 1 bulb per
dimmer)

Cost.
Prices quoted by others seem reasonable at about £15 per channel, possibly
£20 with fault monitoring but that can be optional. The expensive bit is
the
choke. By keeping the dimmer rating low - say 3A per channel ~720W the
chokes are cheaper. for heavy loads you use more than one channel as per
channel assignment above.

Keith









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Automated Home UK
http://www.automatedhome.co.uk
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