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ALADIN SPORT USER MANUAL
Since level stops are more restrictive
than decompression stops, when all
decompression obligations have been
observed the display changes from STOP
DECO to STOP only.
3.9.5
Completing a dive with MB
levels
A dive with MB levels is completed the
same way as a dive without MB levels (see
chapter:
Diving with your Aladin Sport
,
section:
Safety stop timer
) except for the
following exceptions:
If the MB level has been reduced during the
dive, the Aladin Sport will display a flashing
MB level symbol and the current MB level
for 5 minutes after reaching the surface.
The dive is then completed and the Aladin
Sport changes to user mode with the MB
level switching back to the original MB
setting.
Repetitive dives and MB levels: If during a
dive a level stop is ignored and you start
another descent shortly afterwards, the
Aladin Sport might immediately request
level stops. To complete the dive with the
initially set MB level all level stops must be
observed.
3.10 PDIS (Profile Dependent
Intermediate Stop)
3.10.1 Introduction to PDIS
The main purpose of a dive computer is to
track your nitrogen uptake and recommend
a safe ascent procedure. Diving within the
so called no-stop limits means that at the
end of the dive you can ascend directly to
the surface, albeit at a safe ascent rate,
while for dives outside of the no-stop limit
(so-called decompression dives), you must
perform stops at certain depths below the
surface and allow time for excess nitrogen
to be expelled from your body before
finishing the dive.
In both cases, it can be beneficial to stop
for a few minutes at an intermediate depth
between the maximum attained depth
during the dive and the surface or, in case
of a decompression dive, the first (deepest)
decompression stop.
An intermediate stop of this kind is beneficial
as soon as the ambient pressure at that
depth is low enough to ensure that your
body is predominantly off-gassing nitrogen,
even if under a very small pressure gradient.
In such a situation, you can still cruise along
the reef and enjoy the dive while your body
gets a chance to slowly release nitrogen.
In recent times, so called “deep” stops have
been introduced in some dive computers and
tables, defined as half the distance from the
dive’s maximum depth and the surface (or
the lowest decompression stop). Spending 2
or 15 minutes at 30m/100ft would result in
the same deep stop at 15m/50ft.
With PDIS, as the name suggests, the
Aladin Sport interprets your dive profile
and suggests an intermediate stop that
is a function of your nitrogen uptake so
far. The PDI stop will therefore change
through the course of the dive to reflect
the continuously changing situation in
your body. Along the same lines, PDIS
will account for the accumulated nitrogen
from previous dives; hence, PDIS is also
repetitive-dive dependent. Conventional
deep stops completely ignore these facts.
The following figure quantifies the extent
of PDIS and illustrates its dependence on