Дайвинг в Санкт–Петербурге

Lady NAVY

Еще раз, существуют документы под названием "Стандарты ПАДИ". Там все написано. Есе остальное - это домыслы,догадки и отсебятина.

La Bamba

daw

интересно... почитала стандарты КМАС, там прописаны скорее минимальные глубины погружений.

В общем, получается, настоящих стандартов немного, и главные - стандарты страховой компании Smile

. Накажут деньгой в случае чего, и немаленькой.
Стандарты страны и ДЦ - откажут в нырялке.
Рекомендации систем... ну рекомендации, отчего не прислушаться, себя любить надо.

Максим Покомеда · Зарегистрирован: 14.11.2005 Сообщения: 2968

Mausov

господа, а по профилю PDIS кто-нить может объяснить что он делает при активации ? Чем улучшает базовый алгоритм ZH-L8 ADT ? Тут много умных слов. Контора старалась Smile

Кто оценит ?

TABLE OF CONTENTS
. Introduction to PDIS (Profile-Dependent Intermediate Stop) .............................
2. How does PDIS work? ............................................................................................3
3. Special considerations when diving with more than one
gas mixture (PMG) ..................................................................................................3
4. Diving with PDIS .....................................................................................................3
4.1 PDIS during NO STOP diving ...................................................................4
4.2 PDIS during DECOMPRESSION diving ....................................................5
4.3 PDIS during dives with MB levels .............................................................6
Glossary
PDIS: Profile-Dependent Intermediate Stop. This refers to the concept of
introducing an intermediate stop during an ascent.
PDI stop: This refers to the actual stop itself and the depth at which it is to be carried out.
1. Introduction to PDIS (Profile-Dependent Intermediate Stop)
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 offgassing 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 maximum reached depth and the surface (or
the lowest decompression stop). Spending 2 or 15 minutes at 30m/100ft would result in the
same deep stop of 15m/50ft.
English
2
With PDIS, as the name suggests, Galileo 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 continuosly 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 cumulative
nitrogen uptake for two sample dive profiles. This figure also demonstrates the conceptual
difference between PDIS and the rather rudimental “deep” stops.
Specifically, the figure compares two dive profiles to a maximum depth of 40m/132ft
but otherwise very different. Profile 1 stays at 40m/132ft for 7 minutes, then ascends to
30m/100ft for 3 minutes, followed by 12 minutes at 20m/65ft. Profile 2 stays less than two
minutes at 40m/132ft, then ascends to 21m/69ft and stays there for 33 minutes. Both dive
profiles are no-stop dives to the limit of entering decompression. The solid line with triangles
represents the PDIS depth as displayed on the computer screen during the course of the
dive for profile 1, the dotted line with triangles represents the PDIS depth as displayed on
the computer screen during the course of profile 2. One can see that the displayed PDIS
depth increases as more nitrogen is accumulated in the body, but does so very differently
in the two dives due to the different exposure in the two profiles. The PDI stop is carried
out at 25 minutes for profile 1 and at 37 minutes for profile 2, followed by the safety stop
at 5m/15ft.
The solid line with open circles on the other hand represents the depth that would be
displayed by a computer following the conventional deep stop method, and it would be
the same for the two dive profiles. Deep stops completely ignore any facts about the dives
themselves aside for the max depth.
3
2. How does PDIS work?
The mathematical decompression model in
Galileo, called ZH-L8 ADT MB PMG, tracks
your decompression status by dividing
your body into 8 so-called compartments
and mathematically following the uptake
and release of nitrogen in each with the
appropriate laws of physics. The various
compartments simulate parts of your body
such as central nervous system, muscles,
bones, skin and so on.
The depth of the PDI stop is calculated as
that at which the leading compartment for
the decompression calculation switches
from ongassing to offgassing, and the
diver is advised to perform a 2-minute
stop above the displayed depth (this is the
opposite of a decompression stop, where
you are asked to remain just beneath the
displayed depth). During this intermediate
stop, the body is not taking up any more
nitrogen in the leading compartment, but
rather releasing nitrogen (though under
a very small pressure gradient). This,
combined with the relatively high ambient
pressure, inhibits bubble growth.
It should be noted that the two fastest
compartments, with 5 and 10 minutes
half times respectively, are not considered
for the determination of the PDI stop
depth. This is due to the fact that these
compartments are only “leading” for very
short dives, for which an intermediate stop
is not required at all.
F NOTE:
The PDI stop is not a mandatory
stop and it is NOT a substitute for the
3-5 minute safety stop at 5m/15ft.
! WARNING
Even when performing a PDI stop, you still
MUST perform a safety stop at 5m/15ft for 3 to
5 minutes. Performing a 3 to 5 minute stop at
5m/15ft at the end of any dive is still the best
thing you can do for yourself!
3. Special considerations
when diving with more
than one gas mixture
(PMG)
Switching to a higher oxygen concentration
mix during the dive influences the PDI stop.
This needs to be accounted for, in line with
the predictive nature of multigas handling in
ZH-L8 ADT MB PMG.
When diving with more than one gas
mixture, Galileo displays the PDIS depth
according to the following rules:
- if the PDI stop calculated for the bottom
mix (gas 1) is deeper than the switch
depth, than this calculated value is
displayed;
- if the PDI stop calculated for gas 1
is shallower than the switch depth to
the next gas (gas 2 or gas d), then the
displayed PDI stop is a function of the
next gas.
In case of a missed gas switch, Galileo
reverts to the PDI stop for the actively
breathed mix.
4. Diving with PDIS
F NOTE:
To use the PDIS feature, you must set
PDIS to ON in the PDIS menu under
DIVE SETTINGS. The default setting
is OFF.
English
4
When the calculated PDI stop is deeper
than 8m/25ft, Galileo shows it on the display
and continues to do so until you reach the
displayed depth during an ascent. The
displayed value changes during the dive
as Galileo tracks the uptake of nitrogen in
the 8 compartments and updates the PDIS
depth accordingly to reflect the optimum at
all times.
How the PDIS is displayed differs depending
on whether you are in NO STOP or
DECOMPRESSION and on the screen
configuration.
4.1 PDIS during NO STOP diving
In CLASSIC and FULL screen
configurations:
The PDIS depth is shown to the left of the
no-stop time, with the label PDIS. As soon
as you reach that depth during an ascent, a
2-minute countdown will appear in place of
the no-stop value with label PDIS TIMER.
You can have one of three situations:
- you have spent 2 minutes within 3m/10ft
above the indicated depth. The
countdown timer disappears, the PDIS
label and value are replaced by the label
PDIS OK as an indication that you have
performed the PDI stop;
- you have descended by more
than 0.5m/2ft below the PDIS. The
countdown timer disappears and will
reappear again, starting at 2 minutes,
the next time you ascend to the PDIS
depth;
- you have ascended by more than
3m/10ft above the PDIS. The PDIS
label, value and countdown timer
are replaced by the label PDIS NO
to indicate the fact that you have not
performed the PDI stop.
PDIS display (FULL)
PDIS timer (CLASSIC)
PDIS OK (FULL)
PDIS NO (CLASSIC)
English
In LIGHT screen configuration:
The PDIS depth is shown in the MORE
sequence after the O2% and before the
temperature. As soon as you reach that
depth during an ascent, a 2-minute
countdown will appear in place of the
no-stop value with label PDIS TIMER. You
can have one of three situations:
- you have spent 2 minutes within
3m/10ft above the indicated depth while
the timer is showing on the display.
The PDIS label and value in the MORE
sequence are replaced by the label
PDIS OK as an indication that you have
performed the PDI stop;
- you have descended by more
than 0.5m/2ft below the PDIS. The
countdown timer disappears and will
reappear again, starting at 2 minutes, the
next time you ascend to the PDIS depth;
- you have ascended by more than
3m/10ft above the PDIS. The PDIS
label and value in the MORE sequence
are replaced by the label PDIS NO
to indicate the fact that you have not
performed the PDI stop.
F NOTE:
Galileo issues no warnings relating to
a missed PDI stop.
4.2 PDIS during DECOMPRESSION
diving
In CLASSIC and FULL screen configurations,
upon entering decompression the PDIS
information is moved to the lower left
corner and becomes part of the MORE
sequence. This prevents the potential
misinterpretation between the PDI stop and
the decompression stop. Additionally, in
order to avoid conflicts between the PDIS
range and a decompression stop, the PDIS
depth is displayed only if it is 3m/10ft deeper
than the deepest decompression stop.
As soon as you reach that depth during an
ascent, the 2-minute countdown is initiated.
A timer as described in the NO-STOP case
is not displayed here, but the switch of the
label from PDIS to PDIS OK alerts you
when the timer has reached 2 minutes.
Descending by more than 0.5m/2ft below
the PDIS or ascending by more than
3m/10ft above the PDIS follows the same
rules as described in the NO-STOP case.
4.3 PDIS during dives with MB
levels
When diving with MB levels, PDIS follows
the same rules as described above. MB
levels, however, introduce stops earlier
and deeper than the L0 base algorithm. As
such, the PDIS display may be delayed and
for certain dives it may not be displayed at
all. This for instance would be the case for a
shallow dive with air (21% oxygen) and MB
level L5.