Function
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2.2.10
Airflow monitoring
Airflow monitoring is based on the calorimetric measuring method (mass flow rate measuring method).
An airflow sensor is installed in the detector housing in such a way that any change in the sampling pipe (pipe breakage, pipe
blockage) can be evaluated.
If there is an initial reset of the device and the sampling pipe is intact, the data of the airflow measurement is registered and
saved as reference values (100%). The system sets the values in the middle of an electronically formed monitoring window. In
the event of a shift in the values (actual values) out of the monitoring window (±xx%) owing to pipe blockage or pipe breakage
in the sampling pipe, the ASD 532 triggers an “airflow fault”. The monitoring window can be set to different sizes on the
ASD 532.
A variable delay time ensures that disturbance variables, e.g. air turbulence, are ignored. To handle fluctuations in the ambient
temperature, the ASD 532 is equipped with a temperature compensation circuit.
Notice
A requirement for the correct operation of the airflow monitoring is that the airflow is logged when the ASD 532 is
commissioned. With the triggering of an initial reset, the data is acquired and saved in the ASD 532 as reference
values (see also Sec. 2.2.18, “Reset types“).
According to
EN 54-20
a change in the airflow that is greater than
±20%
must be reported as a fault. After the initial reset the
airflow is displayed as 100% in the ASD 532 aspirating smoke detector when the sampling pipe is correct and clean. In the
switch positions
A11
to
C31
any change in this value greater than ±20% – i.e. below 80% (dirt/pipe blockage) or above 120%
(pipe breakage) – triggers an “airflow fault” after the
LS-Ü
delay time of
300 s
has expired.
Warning
Switch positions
W01
to
W44
are stored with airflow monitoring values which are
not tested according to EN
54-20
and may therefore only be used after consulting with the manufacturer.
2.2.11
Smoke sensor monitoring
The smoke sensor used on the ASD 532 is monitored on the AMB 32 Main Board. A failure of the sensor electronics, a dusty
or dirty smoke sensor is registered as an event code and displayed as a state or fault. Likewise, the connection line between
the smoke sensor and the AMB 32 is monitored and a fault is signalled if there is a failure.
To avoid false alarms, the SSD 532 smoke sensors used in the ASD 532 have a technical measure (TM) for comparing fire pa-
rameter pattern matching (measure for verifying the alarm state according to DIN VDE 0833-2).
ASD532 Operating Manual
Summary of Contents for ASD 532
Page 1: ...ASD 532 Aspirating Smoke Detector Operating Manual ...
Page 2: ...2 88 ASD532 Operating Manual ...
Page 6: ...6 121 ASD532 Operating Manual ...
Page 7: ...Document history 7 121 Document history First edition Date 15 10 2015 ASD532 Operating Manual ...
