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"bing2005" schreef in bericht
oups.com...
Hi, guys,
Anyone of you know how did a fire alarm control panel receive a
triggered signal from a detector?
How did the fire alarm control panel know when the detector is
triggered?
Thanks a lot!!!


It depends on the system!

conventional systems use a end off line resistor, the panel measures the
current on the line.
If a smoke detektor is triggerd the detektor uses current and the panel
detect's the used current and will go in to the alarm state.

new analog systems uses a busline, no end off line resitors, the panel
comunicate's with the detektor.
the detector send's measured values to the panel and when the tresshold is
reached the panel tells the detector that it should go in to the alarm
state.

regards

bassie

Hi, guys,
Anyone of you know how did a fire alarm control panel receive a
triggered signal from a detector?
How did the fire alarm control panel know when the detector is
triggered?
Thanks a lot!!!

I can't remember if it's normally open or normally closed, but there is
a little contactor on the fire bottle that changed position when it's
fired. You should be able to figure out with a voltmeter. I'm assuming
you're talking about an engine room halon (or similar) system.

"bing2005" wrote in
oups.com:

How did the fire alarm control panel know when the detector is
triggered?
Thanks a lot!!!


A manufacturer and model number would sure help.....

New fire alarm systems put many detectors on a single pair of wires. The
wires have data and DC on them. Each alarm head has a little computer in
it that has a data address on the wired bus. The computer is powered by
the DC on the wire. Every few seconds, the master panel polls each alarm
head in its directory to check the wires, the status of that particular
control head, to make sure the system is complete and working properly. If
some head, or a group of heads, doesn't answer the call, it alarms in
"trouble" mode, immediately, demanding a technician to fix the system. It
even tells you which head(s) are down in what areas. The little computers
are very intelligent at detecting smoke, fire, temperature, humidity,
flooding, intrusion in secured spaces, etc. Unlike the old analog heads,
there are very few false alarms.

The Halon firebottle in Lionheart's engine space has a pressure switch on
the side of it for alarm panel connections. It switches even if the bottle
leaks to warn of trouble with the Halon...or a fire which melted the link
making it go off. I have this switch hooked to the flooding alarm siren up
the mast. NOONE sleeps while Lionheart floods or burns.

Best analog systems have a resistor at the end of the loops that sets a
specific current at the panel. If it shorts or opens, the resistance is
wrong and the panel alarms. These loops are a big series circuit and any
sensor, window foil, door switch, float switch simply opens the
loop....same as if a burglar cut the wire. Anything opens, the alarm goes
off. The worst analog systems is an open system with all the sensors in
parallel. Being open, there's no way to check continuously for an open
wire, cut line, etc. The digital system is far superior. It alarms to the
position of the exact sensor that went off. Some big ships have a screen
that lights up with an LCD plan of the ship showing the exact location of
all sensors in alarm mode....and what they are measuring, too!

Oh, look, the sensor in the bilge in the forward hold is reporting the
bilge is 4.8' deep in liquid. We'd better see about that....now.

--
Larry

You know you've had a rough night when you wake up and your outlined in
chalk.