34
1 Terminology / Symbols
III Uwatec
®
Aladin
®
Pro Ultra
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 toxicity of oxygen rises with the increase of the porti-
on of oxygen and increasing depth and can limit dive time and the maximum depth. Aladin
®
Pro Ultra
includes this in the calculations and displays the necessary information:
<O
2
%MIX>
Portion of oxygen: The portion of oxygen in the Nitrox mixture can be set bet-
ween 21% (normal comressed air) and 50%.
ppO
2
max
Maximum allowable partial pressure of oxygen: The higher the percentage of
oxygen in the used mixture, the smaller the dive depth at which the tolerable
partial pressure of oxygen (ppO
2
max) is reached. Default setting is a limit of 1.5
bar, it can be changed with the DataTalk-program in the range of 1.2 to 1.95
bar. The Aladin
®
Pro Ultra does not display the entered ppO
2
limit, but warns
the diver acoustically and optically if he reaches the depth at which the ppO
2
limit is reached.
The CNS O
2
%-value/alarm is not influenced by the selected ppO
2
max.-setting.
<CNS O
2
LIMIT>
Oxygen toxicity: With the increased percentage of oxygen, the oxygen in the
tissues, especially in the central nervous system (CNS) becomes important. If the
partial pressure of oxygen rises above
0.5 bar, the CNS O
2
value increases, if
the partial pressure of oxygen is below
0.5 bar, the CNS O
2
value decreases.
The closer the CNS O
2
value comes to
100%, the nearer comes the limit,
where symptoms can occur. See page
36, 37 and 45.
Nitrox diving may only be attempted by
experienced divers with special training.
CNS O
2
%
increases
ppO
2
/depth
0,5 bar
CNS O
2
%
decreases
0,21 bar
WARNING