Re: Medieval Home Automation

["David Buckley" <db@xxxxxxx>]

----- Original Message -----
From: "Andrew Richards" <andrew.richards@xxxxxxx>
Newsgroups: tex.com.ml.ukha_d
Sent: 10 December 2001 22:06
Subject: RE: [ukha_d] Medieval Home Automation


> David
>
> Wow - great set of observations.  Thank you.

'welcome.

>
> Some thoughts in response:
>
> 1. 110 blocks - hmm - understand your point for data feeds and I'll
bring
> those straight back to a patch panel.  But what about control (relay
feed)
> and sensor wires, which don't need to take the whole 8 cores of a UTP
> cable - perhaps just one pair (although in practice I'd allow two
pairs
for
> contingency).  These will be dedicated to the job and so can be routed
> straight to a 110 block and thence to the control cards.  Going to an
RJ45
> socket on a patch panel and then splitting the cores out at the other
end
of
> the patch lead doesn't seem as efficient, or am I missing something?


If you are separating "security" unbalanced circuits from data
and voice
balanced stuff, so that one is on PDS blocks, and t'other is on RJ45, I'd
count that as a reasonable division of labour, and will limit opportunities
to run the two types of data in one cable, if you see what I am hinting at
:-)))


> 2. Tons of home run CAT5 - I quite agree and looked into some form of
> networked intelligence.  Advantech do the ADAM modules, and as you say
> Homevision seems to use Sylva.  But it came down to cost and
complexity.
> CAT5e is very cheap (my thanks to Tracey and others for the pointers
to
> Newey & Eyre - ?25/box if you buy lots), and industrial IO cards
work out
at
> around ?5 per channel (around ?300 for a 64 input or 64 output channel
> card).   ADAM modules are about the same price per channel (Sylva seem
to
be
> about the same, but are limited to 4 cards - max 64 channels), but the
> killer is that they have to be polled to detect state changes, whereas
the
> IO cards raise an interrupt.   I'm going to have over 100 sensor
inputs
> (might even be over 200) and I don't fancy the overhead of polling
that
and
> responding quickly.

I hear you on polling.  But this just needs creative software.  I'm still
running a many year old AppCon system for much of the automation here, and
it polls using RS232 on a windows 3.1 PC (which didnt require any
intervention or rebooting at all during year 2000 - unreal - ghost of bill
strikes back!).   But polling can, as you say,  impact response time.  But
I'd suggest you could poll dozens of adam modules covering hundreds of
sensors several times a second.  I do like the adam kit (in fact, most
things advantech), and it does seem to scale adequately.

> I've seen mention of the Dallas 1-wire detectors (eg for window/door
> open/close, temperature etc), but no idea on costs and complexity. 
What
are
> the per-channel prices like on that & how do you interface to a
control
> system?

Cheap.  For the sensors.  There are other multi-droppable solutions, such
as
iD (used by alarm systems) and cherry CS212 chips, for the electronically
advantaged (and keen).   Again, its software and integration.

> 3. Dimming - DA cards ARE expensive (as are quality dimmers).  Any
sites I
> should look at for digital solutions?

Usual commercials (lutron etc) you already know about.  Casting the net
wider - Look for architectural dimmers with DMX512 control, and then
something like an Artistic Licence DMX Dongle to generate control data.
www.artistic-licence.co.uk, or maybe without the hyphen - you'll soon know
you've got the wrong one!!!  Architectural seems to work out at about 40
quid a channel, which is too much, but the problem is, its all scaled for
1KW per channel.  I'm still waiting for an IGBT based dimmer, fuseless and
MCBless, 300W per channel, 10 channels, in a four inch wide din module.  Oh
and its got to cost a fiver.  If you find one, let me know!

> 5. Earthing and electrics - will check with my electrician friend (I
just
> read the 16th Ed wiring tables and a guide by Trevor Marks, and these
seemed
> say all was OK).  We live some way from the main supply and our PME
earth
is
> poor, hence the need to up the earth - a word for the unwary (like me)
-
the
> elec board is under no obligation to fix a poor earth and you have to
do
it
> yourself

You cant have a poor PME earth, since by definition the earth is generated
by a bond to neutral at your premises.  Not got a dodgy overhead feed or
something?  Earth rods??  May need (a) expert advice, and (b) MCBs if you
cant get the PSCC up high enough....


> 8. IR - my problem is that my control PC will 'dynamically' allocate
sources
> to demand - so if I have (say) 2 DVD players, if the kids demand DVDs
before
> us poor old parents then we'll have to make do with something else
(except
> I'll probably have some form of parental override!).  But on another
day I
> might demand a DVD before the kids and 'grab' one of the players.  As
the
> control PC will be doing the supply/demand matching, only it will
really
> know which way to route the IR command signals - can it be something
as
> simple as relays, or are IR signals at too high a frequency (so do I
go to
> RF relays)?

Ordinary Omron signal relays, G6, will switch just about anything this side
of video, and the critical minimum switched current is something silly like
10 microamps, so the contacts dont get dirty.  G5Y series relays will do
video, TV antenna etc...

> 9. Security cable - how CAN you :-)  What about the mantra "you
can't have
> too much CAT5".  Keith D will kill you !!

Sometimes you just have to be a heretic.  CAT5 is great for just about any
form of balanced signal, but not perfect for unbalanced.  An excellent all
rounder.  But if you are installing from scratch, with a lot of dedicated
cable going to non-movable things like PIRs in the ceiling, why cable with
a
make do cable, when for the same dosh you can have the right cable.

> 11. CCTV - Hmm - back to economics again.  The cable will always be
attached
> to the CCTV, and at around 40p/m I can have a lot of CT100 before I'd
have
> paid for 2 x KAT5 modules.  Or am I being a luddite?

No, you're being sensible.  Just watch for earth loops, or springing 40
quid
for a humbug to get rid of noise bars will destroy the savings.......  I do
like baluns <g>


> 12. Distribution panels - I think my solution is going to be similar -
> except instead of the mains patch panel I was going to have 2 DIN rail
> modules per circuit (13a DS or light), one module for the MCB and the
other
> for the relay/dimmer.  I've yet to check the best relays.  Finder and
> Schrack do quite cheap ones @ ?3 ish that are supposedly rated 16a @
240v.
> But I'm not quite convinced how long they'll last when switching off a
3kw
> load.  For things like cookers I'll have to use contactors

For the washing machine and dryer, I use 20A contactors, which are totally
unstressed, but seem (with the aid of several years hindsight) to be well
OTT.  An X10 appliance module uses a piece of milk bottle top or something
similar, and they seem to last OK...


> 13. ESD - thanks, definitely worth doing.  I was also worried about
> lightning-induced surges - the IO cards are opto-isolated, but I'm not
sure
> if I should be doing anything else - phone lines?

My overhead distribution detector is bleeping again...  Have you got
something specific to declare here...?  I've lost things like MAX232 chips
on long RS232 cables after a lightning bout, so it is possible...