Crowcon Tetra MO7237, User Manual, Page: 8 / 36

Run mode
Your unit is now ready to use.
Below is a typical screen display showing the
unit in normal gas monitoring Run mode.
Familiarise yourself with the gases being
monitored in your unit and make sure you
understand site health and safety procedures
in the event of alarm conditions.
Tetra units with an inbuilt pump will produce
a low humming noise, this is normal.
2. In the event of an alarm
Alarm signals
In the event of gas concentrations exceeding the alarm thresholds for any gas
being monitored, Tetra will activate the alarm signals.
Alarm signals
The red and blue
alarm LEDs will
flash, the sounder
will emit a loud,
fast series of beeps,
the internal vibrator
alarm will activate.
The operator screen
will display the gas in
alarm and the alarm
level. See the figure
to the left.
In the event of an alarm Tetra
CH4 %LEL CO ppm
H2S ppm O2
%
0.0
0.0
0
20.8
OK
OK
Flashing
icon, Tetra
running
normally
Pump
Battery
Screen Icons
Auto zero
Warm up
Confidence signals
In normal Run mode, Tetra will emit a short beep every 0 seconds and the
OK icon flashes to show operational health.
CH4 %LEL CO ppm
H2S ppm
%
0.0
0.0
0
16.7
2
O2
Gas example
under alarm
Alarm icon