RE: comfort fitting

["Dean Smith" <ukha@xxxxxxx>]

I haven't seen it described as a 24hr loop before, the comfort manual
describes it as "dual End Of Line (EOL) resistors".

Essentially 1 resistor (value A) is in the circuit all the time, with a
second (value B)across the contacts of the sensor. This allows comfort to
determine 4 states for the sensor instead of two and therefore detect
cablecuts/tampering i.e.

1) Short Circuit = Fault/Error
2) Resistance of Value A = Sensor contacts closed
3) Resistance of A + B = Sensor contacts Open
4) Open Circuit = Cable cut/fault

I was under the impression it was reasonably common on "good"
alarms - but
could well be wrong.

Of course you dont have to add the resistors to existing sensors, Comfort
has jumper sensors for each zone(input) to determine if they're installed.

Dean

-----Original Message-----
From: Des Gibbons [mailto:des@xxxxxxx]
Sent: 04 March 2003 18:43
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] comfort fitting




>
> 3) comfort has the option to fit a couple of resistors with each
sensor
> so the two conductors can double as a 24 hour loop, this would entail
> opening up each PIR and door sensor (the surface mount magnetic door
> contacts I have had just enough room inside for these), don't know
> whether other alarms have this but I'd never seen it before and it
> seems a good idea.

Hi Alan,


Whats a 24 hr loop for?

Cheers, Des.

http://www.automatedhome.co.uk
Post message: ukha_d@xxxxxxx
Subscribe:  ukha_d-subscribe@xxxxxxx
Unsubscribe:  ukha_d-unsubscribe@xxxxxxx
List owner:  ukha_d-owner@xxxxxxx

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/



http://www.automatedhome.co.uk
Post message: ukha_d@xxxxxxx
Subscribe:  ukha_d-subscribe@xxxxxxx
Unsubscribe:  ukha_d-unsubscribe@xxxxxxx
List owner:  ukha_d-owner@xxxxxxx

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/