MSA ICU Mode D'emploi page 8

7 Use of the ICU
7.1 Monitor Function
The ICU measures the temperature, the motion status, the battery
status, the time, the cylinder pressure. Taking into consideration the
actual breathing, it calculates the remaining service time.
Note: The remaining service time is that time available to the user until
the retreat alarm sounds. This may be the pressure alarm
(usually 60 bar) or the retreat alarm entered manually at the work site
(see 7.5).
For determining the remaining service time the actual breathing rate of
the last 3 minutes is used.
The actual breathing rate is evaluated every 30 seconds and the
remaining service time is recalculated. If the breathing rate increases,
the remaining service time is reduced accordingly.
In order to have reliable data for the calculation of the remaining service
time, the apparatus must be in use for 3 ½ minutes, i. e. the device
cannot determine the remaining service time during the first 3 ½ minutes
of use. For this reason during the first 3 ½ minutes the display shows the
measured pressure. After 3 minutes there are reliable data for the
remaining service time.
This is shown when the LCD automatically displays the change from
pressure to remaining service time. In case of switched on apparatus
and no breathing rate (stand by) the LCD shows the cylinder pressure as
standard display. If then the green button is pushed for determination of
the remaining service time, the display will show three dashes ("---").
The clock symbol during the remaining service time disappears briefly
every 10 seconds. This shows that the integrated real time clock is
functioning properly.
The optional PC software (see 7.7) permits changing the calculation
principle of the remaining service time from pressure alarm (e.g. 60 bar)
to alarm "cylinder empty". In this setting the remaining time is indicated
that is available to the user until the cylinder air is exhausted entirely.
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