Crowcon Gasman - Alarm Indications; Instantaneous and TWA Alarms; Alarm Latching and Muting

Alarm indications Gasman
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IV. Alarm indications
Gasman provides two instantaneous alarm levels, designated level 1 and
level 2. For toxic gas sensors, there are also two TWA alarms, one for short
term exposure (STEL): based on a 15 minute time weighted average, and
the second TWA alarm is for long term exposure (LTEL): based on a 8 hour
time weighted average.
Alarm configurations are set via the Crowcon Portables PC software.
The following settings can be made:
Alarm thresholds for each sensor: Level 1 and level 2
instantaneous alarms.
Alarm trigger: This can be set to rising levels of gas
concentration, or as falling. Oxygen units are set to falling
for deficiency monitoring.
Alarm latching: Alarms can be set to be latched or unlatched. Latched
alarms will require the button to be pressed in order to clear the alarm
oncethehazardhaspassed.Thisisthedefaultsetting.Unlatchedalarms
will clear automatically when the gas hazard has passed, but not until
then.
Alarm mute: The sounder can be set to mute for level 1 alarm only;
pressing the operator button during an alarm condition i.e. presence of
hazardous gas, will silence the sounder and stop the vibration alarm. The
alarm LEDs will continue to flash.
Alarm sounder tone: Different distinctive tones can be selected for the
each alarm condition to achieve the best performance for the monitoring
conditions available.
In the event of a Time Weighted Alarm (TWA)
In the event of the 15 minute or the 8 hour TWA being
triggered, Gasman will go into alarm and display a TWA
warning with the toxic gas readings. Neither the 15 minute
nor the 8 hour TWA alarm can be cleared.