Uwatec Aladin H, User Manual

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36
ALADIN H USER MANUAL
3.10 Diving with 2 or 3 gas
mixtures
D
ept
h
Time
Bottom mix
Deco mix
Diving with 2 gas mixtures
F
NOTE: The following chapter deals
with the characteristics of diving
with 2 or 3 gases. When using 2 gas
mixtures (gas 1 and d), just ignore the
parts describing gas 2.
The Aladin H enables you to use up to 3
different nitrox mixtures during the same
dive. Tank 1 contains the bottom mix
(gas 1), tank 2 the travel mix, and tank d
contains the deco mix (gas d).
Setting the gas mixture and the depth
for changing the gas mixture
Range of O
2
fraction
O
2
fraction
100%
21%
During dives with 2 or 3 gas mixtures the
bottom mix (gas 1) contains the lowest
fraction of oxygen and gas d the highest
fraction of oxygen. The Aladin H will only
accept settings corresponding with this
order.
WARNING
For gas mixtures having an oxygen percentage
of 80% or greater, the ppO
2
is fixed at 1.6bar
and cannot be altered in any way.
Procedure:
1. To enter the setting for the fraction
of oxygen and the ppO
2
max (MOD)
for gas 1 (bottom mix), see chapter:
Settings , section: Gas menu .
2. Repeat the process for gas 2 and the
gas d. Note that in these cases the
resulting MODs correspond to the
depths at which you plan to switch from
gas 1 to gas 2 and from gas 2 to gas d
during the ascent phase.
3. If you set gas 2 and gas d to “– – O
2
%”,
the Aladin H will compute the dive
considering gas 1 only.
The Aladin H will only accept gas switch
depths (MOD gas 2/gas d) as input where
the maximum partial pressures of oxygen
(ppO
2
max) are not exceeded.
F
NOTE:
• During the ascent an audible and visual
attention message will indicate that you
have reached the depth which requires
the change to gas 2 or gas d.
• Without confirmation, the display will
disappear after 30 seconds and your
entries will not be accepted.
• If the oxygen fraction of gas 2/gas d
is set to a value other than “--O
2
%” in
surface mode, and up to a depth of
0.8m/3ft, the Aladin H will display “2G”
or “3G” in the lower right corner of the
display instead of a percentage value.
F
NOTE:
• If you occasionally dive nitrox, you can
use the automatic nitrox reset time to
normal air function. After the reset,
the oxygen fraction of gas 1 is set
to 21%, and the oxygen fractions of
gas 2 and gas d are set to “– – O
2
%”
(single gas dive).