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3.3.3. Alarm thresholds
Each of the three alarm thresholds can be programmed independently for each channel. (See the
“Channel programming” menu).
In normal operation, a gas alarm is only triggered after a preprogrammed time delay in order to
avoid spurious alarms.
Alarm thresholds can be processed in the following manners:
- in normal cycle with manual clearing: block diagram 1,
- in normal cycle with automatic clearing: block diagram 2,
- in parking cycle: block diagram 3.
The alarm thresholds are to be selected according to the gases detected and the corresponding
standards in force.
Special case: A channel connected to a fire detector
- It is MANDATORY to select the scale with 100 divisions.
- It is MANDATORY to select the alarm threshold with 60 divisions.
(Owing to the end-of-loop resistor of 2.7 kΩ, the fire detector outputs 4 mA when no fire is detected
and 20 mA if a fire is detected).
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