RE: Re: [Development] Lights, using two micros.

["Keith Doxey" <ukha@xxxxxxx>]

Individual dimmer modules could be a great way to go.

Onboard 12C508.

8 pins - 2 for power leaves 6.

a.	serial input
b.	Relay Output
c.	Triac Opto drive
d.	Zero cross detect
e.	Address 0
f.	Address 1

Allows 4 different PIC addresses on one serial line from Rabbit
PIC 12C508 or 12C509 is about 70pence. It would do almost all the work in
the dimmer.

Or by having different PICs preprogrammed with the address upto possibly 16
it would leave 2 pins spare on the PIC. By adding a couple of Opto
Isolators
you can get feedback on the true state of the load. EG. Lamps blown, Relay
failed, Triac Short etc and send a message back to the main system
informing
of the problem.

Keith

> -----Original Message-----
> From: Dr John Tankard [mailto:john@xxxxxxx]
> Sent: 03 June 2001 09:53
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] Re: [Development] Lights, using two micros.
>
>
> --- In ukha_d@y..., "Keith Doxey" <ukha@d...> wrote:
>
> > The Rabbit is a very powerful processor caqpable of high level
> comms with
> > the outside world. Let that handle the clever stuff and let a few
> low cost
> > PIC's do the mundane tasks. That way the Rabbit can be a fairly
> general CPU
> > a bit like a PC, and the PIC devices become the
"bolt-ons".
> >
>
> Agreed.
>
> What about the Triac's, fuse, protection relay, maybe opto iso on
> there own board, one board per channel.It might reduce production
> costs 100 boards v 25 and allow users to decide the number of
> channels they need. Also if a triac goes short circuit, the board can
> be replaced without effecting the rest of the unit.
>
> I will try and find my circuit sketches for the prototype, but I am
> certain yours (Keith's) will be much superior. (come to think about
> IRC most of the ideas came from you).
>
> By the way my idea of holding the protection relay closed with the
> triac drive pulse, never got into into the prototype, but i still
> think it could be usefull. It also means you can still switch off a
> unit with a short circuit triac, as shortly after the drive pulse
> stops the protection relay will open. What do you think Keith ?
>
> John
>
>
>
>
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