OPERATION
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5.10 RESETTING ALARM AND FAULT CONDITIONS
In latching mode, alarms and faults will continue to be indicated and signalled, even if the original
cause has been removed. The detector needs to be reset to clear the condition. The detector can be
reset by activating the wired input or remotely using the walk-test trigger tool. During the reset the
indicators and outputs will be turned off but if the alarm or fault is still present the condition will
be re-established. The detector will perform re-tests if necessary, such as an OPM test, to determine
if faults have cleared.
5.11 SELF-TEST
The FV300 detector performs a regular self-test of the electronics and monitors the interfaces in
the detector. This occurs automatically at pre-set timed intervals and does not disturb the normal
operation of the detector. If a fault is detected it will be indicated and signalled as described in
section 5.7.
5.12 OPTICAL PATH MONITORING
(OPM) TEST
The FV300 detector can check the cleanliness of the window used by the array and other optical
sensors. The detector flashes a lamp that radiates IR at the same wavelength used for fire detection
for about 5 seconds. The lamp shines onto a mirror that reflects the energy back through the
window onto a specific section of the array. The detector analyses the reflected signal to assess if
the window is dirty.
The OPM test can be initiated manually, on demand, using the walk-test trigger tool, the walk-test
wired input or from the field bus interface. When the OPM test is activated manually, a single test
is performed and the result reported on the indicators and outputs. If the window is considered to
be dirty or obscured then an OPM fault is reported. The fault will be cleared when the window is
cleaned and the test re-run to give a clean result. Requests for a manual OPM test will be ignored
if the detector is in alarm, pre-alarm or performing an alarm test.
Alternatively, the detector can be configured to perform the OPM test automatically at regular
intervals by setting a DIP switch (OPM Man/Auto). The default is automatic OPM testing. The
time interval can be adjusted using the PC configuration tool. The default OPM test interval is
every 20 minutes. The first OPM test will be made 20 minutes (or the configured time) after power-
up. The regular OPM test will be delayed if the detector is in alarm, pre-alarm or performing an
alarm test. A manual OPM test can be initiated at any time when the detector is in automatic OPM
mode and will produce an immediate test result reported on the indicators and outputs as described
above.
If the automatic OPM test detects the dirty condition (5-50%) for 20 successive tests then an OPM
fault is reported. If the window is considered to be obscured (<5%) then the OPM test interval
reduces to 5 minutes and if the window remains obscured for 5 further tests then an OPM fault is
reported. The obscured condition is thus detected and reported much faster. Either fault will be
cleared when the window is cleaned and the test re-run to give a clean result. The test can be
activated manually after cleaning rather than waiting for the next timed automatic test.
The detector is fitted with 2 lamps. These are used alternately to maximise their lifetime. If a lamp
should fail then the detector can continue using the one lamp without reporting a fault. The failure
of both lamps will be reported as a hardware fault.
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