Re: Re: Sensors / Switches / etc

["Dave McLaughlin" <dave@xxxxxxx>]

Hi David,

Ah, someone else who uses the old Quantech HA system. In my old house I
used to use the system myself. I have not fitted it to the new house cause
SWMBO does not like all the wiring it involved (I was single at the time I
installed it) Even at 2400 bps it was fast enough to be able to have 30
units on the network and be able to detect which direction someone was
travelling by the use of 2 floor mat sensors.

I noticed just recently that Quantech website has gone along with the
company. I think Peter Scargill, who owned it, has moved on to something
else. Pity, as he was very helpful and the system was very cheap.

How many units do you have in your house? All mine are still in boxes and
probably going to gather dust for the foreseeable future.

I am now a CAN bus fan myself but have some use of RS485 for some stuff I
do or plan to do.

Regards
Dave...
----- Original Message -----
From: David Buckley
To: ukha_d@xxxxxxx
Sent: Tuesday, April 15, 2003 6:30 PM
Subject: [ukha_d] Re: Sensors / Switches / etc


--- In ukha_d@xxxxxxx, "Dan" <dtoma@f...> wrote:

> My opinion for the best approach is to mix between ethernet and a
> single-wire bus devices, with the cost as the main selection
factor. This
> can be a lot more difficult to design, but... this is not the nice
> part?...;-)

Since the late 90's I've had AppCon HA modules round the house(no
longer available, as far as I can tell) and it uses a single wire
serial system, and is rock solid reliable.  It does not have a
required topology (ie star or bus), so you can bend it any way you
like.  Its 2400 baud, which is slow but adequate.  It uses a pullup
resistor to 12v, so reading the bus is just a potential divider, and
driving it is a transistor.  A cheaper driver is hard to imagine.

Now officially, of course, I'm an RS485 fan.  Again, 'cos its
reliable.  And in my opinion, the primary requirement for core HA
sensors and actuators is relaibility.

David.

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