1.3 Nitrox information (O
2
information)
For dives with compressed air in normal recreational diving, nitrogen is the decisive gas for the decom-
pression calculations. When diving with Nitrox, the risk of oxygen toxicity rises with the increase of the frac-
tion of oxygen and the increase of depth and can limit dive time and the maximum depth. Aladin
®
inclu-
des this in the calculations and displays the necessary information:
<O
2
% MIX> Fraction of oxygen: The fraction of oxygen in the Nitrox mixture can be set bet-
ween 21% (normal compressed air) and 50% (TEC:100%) in 1% increments.
Your selected mix will be the basis for all calculations.
ppO
2 max.
Maximum allowed partial pressure of oxygen: the higher the fraction of oxygen
in the mixture, the shallower the dive depth at which this value of the
partial pressure of oxygen is reached. The depth at which ppO
2
max. is reached
is called Maximum Operating Depth (MOD).
When you enter the settings for the gas mixture, Aladin
®
will display the ppO
2
max. limit setting and the cor
responding MOD. Aladin
®
warns the diver audibly
and visually once the depth is reached at which the ppO
2
reaches the maximum
allowed value ->23.
• Default setting of ppO
2
max. is 1.4 bar.
TEC
The value of
ppO
2
max. can be set by means of SmartTRAK or with
"
set 1
"
between 1.2 and 1.6 bar (->40). It can also be reduced at the time of setting the
gas mixture (->18).
• The CNS O
2
% value/alarm is not influenced by the selected ppO
2
max. setting.
<CNS O
2
> Oxygen toxicity: With the increased
percentage of oxygen, the oxygen in
the tissues (especially in the central
nervous system (CNS)) becomes im-
portant. If the partial pressure of oxy-
gen rises above 0.5 bar, the CNS O
2
value increases, if the partial pressu-
re of oxygen is below 0.5 bar, the
CNS O
2
value decreases. The closer
the CNS O
2
value is to 100%, the
closer the limit where symptoms can
occur. See page 23.
Nitrox diving may only be attempted by experienced divers after proper training
from an internationally recognized agency.
16
1 Terminology / Symbols
III UWATEC
®
Aladin
®
dive computers
