Chemical Sensor (Gas Sensor); System Description; Flash Frequency And Error Detection; Features - Bosch AVENAR 4000 FAP-425-O User Manual

6 en | System Overview
2.1.3

Chemical Sensor (Gas Sensor)

The gas sensor detects mainly the carbon monoxide (CO) that
is produced by a fire, but it also detects hydrogen (H) and
nitrogen monoxide (NO).
The underlying measurement principle is CO oxidation and the
measurable current that it creates. The sensor signal value is
proportional to the concentration of gas.
The gas sensor supplies additional information in order to
reliably suppress disturbance variables.
2.2

System Description

Up to three characteristics are integrated in FAP-425/FAH-425 series detectors:
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Rotary switches (R) enable automatic or manual addressing. The individual sensors are
programmed via the LSN network manually via the FSP-5000-RPS programming software. All
sensor signals are analyzed continually by the internal signal analysis electronics (ISP) and are
linked with each other. By linking the sensors (combined detectors), the detector can also be
used in places where the work carried out gives rise to light smoke, steam or dust. If a signal
combination fits the selected identifier for the area of operation for the detectors, an alarm is
triggered automatically.
2.3

Flash Frequency and Error Detection

The LSN improved detector has one centrally positioned two-color LEDs that flash green to
display the operational status.
The green LED on LSN improved FAP-425/FAH-425 series detectors is deactivated when
delivered. It can be activated as required via the programming software.
The LSN improved detector permanently monitors and adjusts itself throughout its life cycle in
order to adapt its sensitivity to the set threshold value.
A message is sent to the fire panel if the detector becomes too contaminated.
The LED will start to flash red as soon as an alarm is triggered.
The detector will return to its normal operating condition when the alarm is canceled via the
control panel or if the alarm cause disappears.
2.4

Features

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2021-11 | 4 | F.01U.283.550
Optical (for smoke): O
Dual-optical (for smoke): DO
Thermal (for heat): T
Chemical (for CO gas): C
Active self-monitoring of the sensors, with display on the fire panel:
– Active adjustment of the threshold (drift compensation) if the optical sensor
becomes contaminated.
– Active adjustment of the threshold (drift compensation) of the chemical sensor.
EMC safety is up to 50 V/m and is therefore much higher than normatively required.
Preservation of LSN loop functions in the event of wire break or short-circuit of a detector
through integrated isolators.
Individual detector identification on the fire panel in the event of an alarm. Alarm
indication on the detector with a flashing red LED.
Programmable, i.e. can be adjusted to the area of operation.
User manual
AVENAR detector 4000
3
Chemical sensor
Bosch Sicherheitssysteme GmbH