Technical information
3. Meridian as a dive computer
3. Meridian as a dive computer
35
English
SCUBAPRO MERIDIAN
WARNING
Flying while Meridian displays the NO FLY
symbol can result in serious injury or death.
3.7.2 Altitude and the
decompression algorithm
Atmospheric pressure is a function of
altitude and of weather conditions. This
is an important aspect to consider for
diving, because the atmospheric pressure
surrounding you has an influence on
ongassing and offgassing of nitrogen.
Above a certain altitude, the decompression
algorithm has to change in order to account
for the effect of the change in atmospheric
pressure.
Meridian divides the possible altitude
range in 5 classes that are illustrated in the
illustration below:
Elevation
Altitude
Class
Barometric
switch point
Dive
Computer
mode
4000 m
13120 ft
C4 610 mbar
8.85 psi
GAUGE
(no deco
data)
3000 m
9840 ft
C3 725 mbar
10.51 psi
SCUBA
2000 m
6560 ft
C2 815 mbar
11.82 psi
SCUBA
1000 m
3280 ft
C1 905 mbar
13.13 psi
SCUBA
0 m
0 ft
C0 SCUBA
The Altitude Classes are defined in terms of approximate elevations because the effect of
weather conditions can make the pressure switch point occur at different levels.
WARNING
At Altitude Class 4, Meridian functions in
GAUGE mode only (automatic switch from dive
computer mode).
F
NOTE: You can check your current
Altitude Class and elevation by
activating the altitude meter. Refer to
chapter Checking the Altitude on
how to do so.
F
NOTE: Meridian monitors the
altitude automatically: it monitors
the atmospheric pressure every
60 seconds and if a sufficient drop in
pressure is detected, the following will
occur it does the following:
• A new Altitude Class will be indicated
and if applicable, the prohibited
Altitude Class too;
• The desaturation time will be indicated,
which in this case is an adaptation to
the new ambient pressure. If a dive is
started during this adaptation time,
Meridian considers it a repetitive dive,
since the body has residual nitrogen.
3.7.3 Prohibited altitude
Increasing altitude, as well as flying after
diving, exposes your body to a reduced
ambient pressure. In a way similar to the
no-fly time, Meridian advises you as to
which Altitude Classes are safe after a dive
and which are not. For example, if you must
drive over a mountain pass to return home
after a dive, it can be quite important to
have this information.