Detectors
Working principle
Optical: light scattering principle: If the wavelength of light is less than the particle size,
light gets scattered by that particle. All optical detectors will have an LED and a
photodiode. When the smoke particles enter the smoke chamber, the light from LED
gets scattered by the smoke particles and falls on photodiode generating a current .All
Bosch LSN improved detectors has an intelligent signal processor to process the
electrical signal and compare it with about 5000 stored values, to decide whether to
give alarm or not.
Thermal: A thermistor in a resistance network is used as a thermal sensor, from which
an analog-digital converter measures the temperature-dependent voltage at regular
intervals.
Depending on the specified detector class, the temperature sensor triggers the alarm
status when the maximum temperature of 54 °C or 69 °C is exceeded (thermal
maximum), or if the temperature rises by a defined amount within a specified time
(thermal differential).
Chemical sensor (CO gas sensor)
The main function of the gas sensor is to detect carbon monoxide (CO) generated as a
result of a fire, but it will also detect hydrogen (H) and nitrous monoxide (NO). The
working principle is the CO oxidation of an electrode and the current arises from this.
The sensor signal value is proportional to the concentration of gas. The life time of
chemical sensor is five years.
General Features:
360 degree view of fire indicator LED(therefore the detector bases can be
aligned in any direction)
Drift compensation: the threshold level for alarm for each detector varies in
response to outside pollution level (for eg. if the environment pollution is high,
the threshold level also increases), preventing false alarms.
The detector bases have a mechanical removal lock (can be
activated/deactivated)
Every detector base has a “Chamber Maid Plug” (a cleaning opening with a plug)
for blowing out the optical chamber with compressed air (not required for the
FAH-T 420( Heat Detector).
Intelligent Signal Processor(For all LSN 420 series detectors) with about 5000 in
built smoke patterns
Automatic or manual detector addressing selectable.
Use of shielded and unshielded cables.
Activating the Mechanical Removal Lock
MS-400 Base
Break the bolt ‘X’ Inset it in to the slot as shown.
Put the detector into the base
and turn it clockwise….LOCKED…
Removing a locked Detector
Insert a screw driver into the unlocking
opening and push the bolt upward. At the
same time turn the detector anti
clockwise.
Address Settings:
Automatic Addressing
Manual
Addressing
If any LSN classic element is used all the
detectors and devices in the loop/stub should be
set to “CL” mode. In this case the max. number
of elements is limited to 127
Chamber Maid Plug (For detector cleaning by blowing compressed air)
FAP-O FAH-T FAP-OT 420 FAP-OTC 420
420 420
Detector Type Optical Thermal Optical/Thermal Optical/Thermal/Chemical
Operating 15..33V 15..33V 15..33V DC 15..33V DC
voltage DC DC
Current < .51mA < .51mA < .51mA < .51mA
consumption
Monitoring Area 120 sq. 40 sq. m 120 sq. m 120 sq. m
m
Max. installation 16 m 7.5 m 16 m 16 m
height
Color code No Red loop Black loop Yellow loop
marking
FAP-DO 420 FAH-DOT 420 FAP-DOTC 420 FAP-520
Detector Type Dual Optical Dual Optical Dual Optical Thermal Chamber
Thermal Chemical less
Operating voltage 15..33V DC 15..33V DC 15..33V DC 15..33V DC
Current < .51mA < .51mA < .51mA < 3.25mA
consumption
Monitoring Area 120 sq. m 120 sq. m 120 sq. m 120 sq. m
Max. installation 16 m 16 m 16 m 16 m
height
Color code Dual Gray Dual Red Dual Black loop Minimum Distance to
loop loop lamps for FAP-520 is 0.5 m
RPS Programming: If this option is selected, the detector
will send the “Fire” message to the
A “Pre-Alarm” message is sent to panel only if any two detectors in the
the panel if any one detector same group detect fire.
detects fire, for both “Dual group”
& “Dual detector “dependencies
The “Fire” message will be sent
to the panel only if any detector
from both groups detects fire.
If any detector detects fire, it will internally
store it and wait for a certain period of time Resets the selected
(Reset after?) for the same detector to detect output for a certain
fire again. If fire is detected again within the period of time in case
“Reset after” period the “Fire” message is of “Fire” message sent
sent .The max. for “reset after” is 30 seconds to the panel
To “bypass” or “block” the
To connect remote indicator
detector from the panel
To activate green LED
blinking on the detector
This will be the sensitivity of the detector
when key is programmed for “Alter
Sensitivity” under panel administration. For
details refer key programming presentation.
Note: Please refer the detector planning notes for “Sensitivity settings”
