Cressi Archimede II User manual

Cressi-sub S.p.A.
Via Gelasio Adamoli, 501 - 16165 - Genova - Italia
Tel. [phone] - Fax [phone]
E.mail: [email protected]
WWW: http://www.cressi-sub.it
Manuale d’istruzioni
Manuel d’instructions
Gebrauchsanweisung
Manual de instrucciones
User’s Manual
Cressi-sub S.p.A.
Via Gelasio Adamoli, 501 - 16165 - Genova - Italia
Tel. [phone] - Fax [phone]
E.mail: [email protected]
WWW: http://www.cressi-sub.it
Manuale d’istruzioni
Manuel d’instructions
Gebrauchsanweisung
Manual de instrucciones
User’s Manual

User’s Manual
User’s Manual
ENGLISH
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TABLE OF CONTENTS
1. - INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag. 161
1.1. - Main specifications . . . . . . . . . . . . . . . . . . . . . . . . . . pag. 161
1.2. - Safety measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag. 161
1.2.1. - Definitions of danger, warning and note. . . . . . . . pag. 161
1.2.2. - General recommendations and safety measures . pag.162
1.3. - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.163
2. - BEFORE DIVING . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.165
2.1. - UFDS display and controls. . . . . . . . . . . . . . . . . . . . pag.166
2.2. - On surface, before diving . . . . . . . . . . . . . . . . . . . . pag.166
2.3. - Parameters setting . . . . . . . . . . . . . . . . . . . . . . . . . . pag.167
2.3.1. - Dive program parameters setting ( ).........pag. 167
2.3.2.- Dive planning ( ). . . . . . . . . . . . . . . . . . . . . . . . pag.169
2.3.3.- Rapid visualisation of set data ( ) . . . . . . . . . . pag.169
2.4. - program parameters setting
(depthometer/timer). . . . . . . . . . . . . . . . . . . . . . . . . pag.169
2.5. - Instrument general setting . . . . . . . . . . . . . . . . . . . pag.170
2.5.1. - Maximum depth alarm. . . . . . . . . . . . . . . . . . . . . . . pag. 170
2.5.2.- Date and time adjustment ( ) . . . . . . . . . . . . . pag. 171
2.5.3.- Units of measure setting . . . . . . . . . . . . . . . . . . . . . pag. 171
3. - WHILE DIVING: PROGRAM DIVE . . . . . . . . . . . pag.173
3.1. - Air dive ( ) . . . . . . . . . . . . . . . . . . . . . . . . . pag.173
3.2. - Nitrox mixtures dive ( ). . . . . . . . . . . . . . . . pag.174
3.2.1. - Before a Nitrox dive . . . . . . . . . . . . . . . . . . . . . . . . pag.174
3.3. - Nitrox parameters setting . . . . . . . . . . . . . . . . . . . . pag.174
3.3.1. - PO2 partial pressure setting . . . . . . . . . . . . . . . . . . pag.174
3.3.2.- Nitrox mixture/s oxygen fraction F02 setting . . . pag.175
3.3.3.- Mixture changing while diving . . . . . . . . . . . . . . . . pag.176
3.3.4 - CNS toxicity display ( ) . . . . . . . . . . . . . . . . . . . . pag. 177
3.3.5.- PO2 alarm ( ). . . . . . . . . . . . . . . . . . . . . . . . . . . pag.178
3.4. - Curve dive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.178
3.4.1. - Ascent rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.178
3.4.2.- Safety Stop ( ) . . . . . . . . . . . . . . . . . . . . . . . . . pag.179
3.4.3.- Decompression forewarning ( ) . . . . . . . . . . . pag.179
3.5. - Decompression dive ( ) . . . . . . . . . . . . . . . . . pag.180
3.5.1 - Omitted decompression stage alarm . . . . . . . . . . pag. 181
3.6. - program (depthometer/timer) . . . . . . . . . . . pag. 181
4. - ON SURFACE AFTER A DIVE . . . . . . . . . . . . . . . pag.183
4.1. - Data processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.184
4.1.1. - Surface interval ( , , ) . . . . . . . . . . . . . . pag.184
4.1.2. - Logbook ( ). . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.185
4.1.3. - Dive historic memory ( ) . . . . . . . . . . . . . . . . . . pag.186
4.1.4. - Dive profile ( ) . . . . . . . . . . . . . . . . . . . . . . . . . . pag.187
4.1.5. - Data PC transfer: compatible PC interface ( ) pag.187
4.1.6. - Instrument reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.188
4.2. - Simulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.188
4.2.1. - Dive simulator ( ). . . . . . . . . . . . . . . . . . . . . . . . pag.188
4.2.2.- Surface interval dive simulator ( ). . . . . . . . . . pag.189
5. - CARE AND MAINTENANCE. . . . . . . . . . . . . . . . . pag.189
5.1. - Battery replacement. . . . . . . . . . . . . . . . . . . . . . . . . pag.190
6. - TECHNICAL SPECIFICATIONS. . . . . . . . . . . . . . pag. 191
6.1. - No decompression limits by the first dive
in a series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.192
6.1.1. - Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.192
7. - WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pag.193
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1. - INTRODUCTION.
Congratulations on your purchase of the Archimedes II com-
puter. The Archimedes II is a sophisticated computer offering
numerous performance features which ensures the utmost
in performance, reliability and safety.
1.1. - Main specifications.
• Algorithm. The Bühlmann ZH-L8 algorithm has been refi-
ned by Randy Bohrer in order to make available a more
complicated RGBM program. The result is an algorithm
very similar to ZH-L16 which is less penalizing related to
water temperature and exceeding ascent rates.
• Tissues: 12 Tissues with saturation hemi-phases between
5 and 640 minutes;
• PROGRAM
Dive data full processing. During air or Nitrox dives (including
decompression dives) two different nitrox mixtures may be
utilized.
• Setting of mixtures. P02 can be set between 1.0 bar to 1.6
bar. FO2 settings between 21% to 50% and 21% to 99%.
• The Archimedes II will allow for a nitrox dive subsequent to
an air dive even during de-saturation.
• Possibility of PROGRAM setting (depthometer/timer)
• Large UFDS display system allows for ease in reading and
understanding of values.
• Replaceable display protecting screen
• Battery replacement by user
• Manual dive planning (Scrolling)
• Unit of measure changing from metric to feet and °C to °F.
• Sound and visual warning systems
• Nitrogen saturation graphic indicator
• CNS oxygen toxicity graphic indicator
• Back-luminescent display
• Dive simulator (surface interval setting for a subsequent dive)
• Calendar and clock
• Logbook (30 h or 60 dives) including dive profile
• Dive historical memory
• Reset button allows for multi diver activity.
• PC interface (optional)
1.2. - SAFETY MEASURES.
1.2.1. - Definition of danger, warning and note.
Please read the user guide thoroughly prior to using the
Archimedes II.
Prior to reading the operational directions, please understand
the following definitions:
 DANGER: indicates a situation (or procedure) that
may be dangerous to the diver’s health and safety.
WARNING: indicates a situation (or procedure) that may
be dangerous to the diver or damage the instrument
NOTE: stresses important information.
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1.2.2. - General recommendations and safety
measures.
WARNING: Read the directions! Please read users’
guide carefully, including the safety measures section.
Have a thorough understanding of the instrument’s use,
functions and limitations before using it! DO NOT use the
instrument without having read each chapter of the users’
guide!
 DANGER: A underwater diving computer can never
completely eliminate the risk of decompression sickness.
The computer does not take into any account a diver’s
physical conditions which may vary daily. It is recommen-
ded that a medical examination is completed prior to com-
mencing any underwater diving activities, and to assess
one’s own physical condition before each dive.
Circumstances such as cold water temperature (less than
10°C – 50F), poor physical condition, multiple dives made
on subsequent days, weariness, use of alcohol, drugs, or
medication and dehydration my increase the risk of
decompression sickness.. It is recommended to avoid all
such situations that may increase the likelihood of decom-
pression sickness.
WARNING: The Archimedes II should be used only by
properly trained and certified divers. No computer will
replace proper underwater training.
WARNING: The Cressi-sub Archimedes II computer is
designed for recreational sport diving only. It is not desi-
gned for commercial use requiring increased diving activity.
WARNING: Before using the computer, please check the
battery life status and the visibility of the LCD display. DO
NOT dive if the instruments’ indications are not clear and if
the battery is low.
WARNING: While diving, be equipped with a depth
gauge, diving watch and dive tables. Additionally, check
the air capacity in your diving cylinders.
 DANGER: Do not dive at high altitudes before the
instrument has automatically switched on the program
corresponding to the altitude at which you are. Please
check the altitude level on the display. Please be advised
that diving at higher altitudes than 9,842 ft. above sea level
involves an increase risk of decompression sickness.
 DANGER: Before flying, wait until the icon "No Fly
Time" on the computer display has disappeared.
WARNING: The information offered on the computer is
strictly personal for the individual who used the instru-
ment during a dive or a series of dives.
 DANGER: Cressi-sub discourages the use of this
instrument in decompression dives. In the event that no-
decompression has been exceeded, the Archimedes II
Cressi-sub computer will display information related to
decompression, surfacing and surface interval times.
WARNING: Do not dive using Nitrox mixtures without
checking the contents and correct O2 percentage (FO2).
After doing so, set your computer with the mixture(s)’
value so that it may process the decompression compu-
tations. Please be advised that the computer only accepts
FO2 values to the nearest whole number. (i.e. 36% not
35.8% )
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DANGER: The use of nitrox should not be undertaken
without proper training. Nitrox dives will expose the diver
to different risks than those of air dives, including serious
physical damage and, in extreme cases, even death.
 DANGER: As a safety measure the Archimedes II
computer utilizes a PO2 limit set at 1.4 bar even for air
dives. Should you require an additional safely margin, it is
possible to set PO2 at lower values, down to 1.0 bar, by
decrements of 0.1 bar.
WARNING: After a dive with the Archimedes II set in Gage
mode (depth meter-timer). The instrument will not make
saturation and de-saturation computations during the
remaining 48 hours elapsing from the depth meter’s use.
WARNING: Avoid diving activities that result in unsafe
profiles such as "yo-yo" dives, dives with reversed profiles
or several subsequent dives during subsequent days.
Diving activities such as these are potentially dangerous
and present a higher risk of decompression sickness.
WARNING: Please utilize the most conservative safety
factor at all times. By doing so, you will dive more conser-
vatively, which will minimize the likelihood of decompres-
sion sickness.
NOTE: While flying, the Archimedes II must be stored in
the pressurized cabin.
NOTE: Cressi-sub strongly recommends that all sport
diving activities be conducted within the guidelines of no-
decompression diving and at a maximum depth of 132 ft.
Exceeding these perimeters dramatically increases the
likelihood of decompression sickness
As a result of technological advancements/changes, Cressi-
sub reserves the right to modify the Archimedes II computer
without notification.
1.3. – Introduction.
The Archimedes II computer is a multifunctional instrument
for sport diving. It will supply information on depth, dive times,
decompression status, ascent rate, and surfaces interval
time between dives. Nitrogen absorption and release is con-
tinuously processed by it’s sophisticated software.
Information is displayed in large characters on the
Archimedes II’s
User Friendly Display System (UFD). This
system allows for easy and direct dialogue between the diver
and the computer, ensuring a clear understanding of all the
data needed at any given time.
Additionally, the computer is equipped with a watch and
calendar, a multifunctional dive memory (logbook), and a dive
simulator.
The Archimedes II’s mathematical model can make satura-
tion and de-saturation computations of dives carried out with
air, and with up to two different nitrox mixtures. These may be
selected during the dive itself. Nitrox mixture(s) dives may be
set from the maximum PO2 value between 1.0 and 1.6 bar to
oxygen percentage (FOG): the primary (MIXI) between 21% -
50% for O2, the second (MIX2) between 21%-99%.
Additionally, the computer may be set by the user for either
metric (m -°C) or feet (ft. -°F).
Archimedes II Cressi-sub underwater computer may be
connected to a compatible PC, by means of a Cressi-sub
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164
interface (accessory) and its related software Cressi PC
Logbook (accessory).
Please note that it is very important to read and understand the
users guide and the operation of the Archimedes II. Serious
damages or death can result if theses guidelines are not clearly
understood.
Archimedes II Cressi-sub computer’s watch and calendar
function (see picture 1) are always on, and the related battery
consumption is unnoticeable.
Operational functions are easily visible either by depressing but-
tons B (Mode), A or C, or when the contacts get wet during a
diving activity (the dive program turns on at a depth greater than
5 ft. and are illustrated by the figures shown on its large display.
In order to understand all the computer’s functions and their
meaning, the guide is divided into five main chapters, dealing
with every possible situation:
• 1 - Introduction and safety measures
• 2 - Before diving
• 3 - While diving
• 4 - On surface after diving
• 5 - Care and maintenance
The Archimedes II is designed to be easily understood and
operated. It displays only the data needed during specific
situations.
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2) Before diving
2) Before diving
Foto Ghisotti
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2.1. - UFDS display and controls.
Archimedes II computer is equipped with a “ User Friendly
Display System
” (UFDS) display, which “escorts” the diver
during its operation. Various icons on the display will indicate
the operation that may be carried out at that moment. As an
example, the “light” icon ( ) (at the bottom on the right) indi-
cates that by depressing button C the back-illumination will
be engaged. This establishes a direct “dialogue” and a clear
understanding of every function.
Archimedes II’s different programs are visible by repeatedly
depressing button B (Mode). This is the key to operating the
system. They are clearly indicated by the alpha-numeric
UFDS display. Some programs have sub-menus, which are
switched on by depressing buttons A and C. This will allow as
well as change the setting on the surface. Depressing button
C ( ) engages the display back-illumination.
2.2. - On surface, before diving.
As previously noted, the Archimedes II is always on. When
diving at altitude, it is important to check that the appropriate
altitude adjustments have occurred. This function is carried
out automatically, updating every 10 minutes. Altitude adjust-
ment values will be displayed as follows:
no icon ( )- from 0 – 2.625 ft. (picture 1)
- from 2.625 – 5.250 ft. (picture 1-a)
- from 5.250 – 7.874 ft.
- from 7.874 – 19.685 ft.
- more than 19,685 ft. -out of range
Each icon indicates that the computer has automatically
modified its own mathematical model to adjust to proper
altitude.
 DANGER: Diving at altitudes greater than 9,842 ft.
above sea level involves an increased risk of decompres-
sion sickness.
Diving at higher altitudes than normal may cause alterations
of the nitrogen balance between the human body and the
environment.
AC
B
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167
IIt is recommended that before diving at altitude, wait at least
three hours after arriving at your diving destination. This will
allow a partial release of the residual nitrogen from the body.
The atmospheric pressure at higher altitudes is lower than at
sea level. Therefore, the diver has additional nitrogen in his
body than at the lower altitudes. The excess is gradually
released and the balance re-established within a couple of
days. At this point it is important to check:
The low battery indicator. It should not be on or flashing (pic-
ture 2 a-b).
The computer display is operating. All liquid crystal segments
should be displaying.
WARNING: Should the display show the symbol of a low
battery (picture 2 a-b), the computer must NOT be used.
Additionally, should it display during a dive, the diver must
immediately surface. A battery replacement is required as
outlined in chapter 5.
2.3. - PARAMETERS SETTING.
In order to set the dive’s parameters, you must depress the
central button B (Mode), and the icon relating to the program
you want to use will be shown (picture.3): , for air dives
( ) or Nitrox, mixture(s), or if you want to use
the depth meter /timer program.
NOTE: Archimedes II computer is preset on pro-
gram.
2.3.1. - DIVE program parameters setting.
NOTE: Archimedes II computer is preset on pro-
gram.
This is the basic program with which the Archimedes II is set.
It is possible to modify its parameters by repeatedly depres-
sing button A ( ), which allows you to select, in the following
order, the dive’s parameters relating to:
PO2 Mix 1 -> FO2 Mix 1 -> PO2 Mix 2 -> FO2 Mix 2
-> Safety Factor -> Max Depth -> OFF/ON -> DIVE
that is:
• PO2 Mix 1 is the partial pressure of the former of the two
Nitrox mixtures, so that Archimedes II can make its decom-
pression computations. The diver can set it on values
between 1.0 bar (included) and 1.6 bar (included), by varia-
tions of 0.1 bar, obtained at each pressure of button C ( );
NOTE: By varying of max PO2 setting (picture 3), the com-
puter also indicates the maximum depth (MAX) that may be
reached with that mixture.
WARNING: Both mixtures’ PO2 factory set on a basic value
(default) of 1.4 bar, both for air dives and for Nitrox mixture
dives. The diver is then following the most conservative
values recommended for sport dives. Different PO2 values
may be set as shown in chapter 3.3. The set value will be
memorized in the computer until the diver chooses another
setting.
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168
• FO2 Mix 1 is the oxygen percentage of the primary Nitrox
mixture (MIX1) set on Archimedes II. The diver may vary it on
values between FO2=Air (21%) – basic setting - and FO2=50
% (included), by variations of 1% O2, obtained at each
depression of button C ( );
WARNING: Archimedes II is factory set with the primary
Nitrox mixture on Air (FO2=21%) and the second additional
mixture on Off (FO2= - -%)
NOTE: During the phase of parameters’ setting, by depres-
sing button C ( ), the computer will automatically stop on
standard Nitrox 1 mixture (EAN 32), with an oxygen percen-
tage of 32%. By keeping button C ( ) depressed, it will stop
on (Air) setting. This is to allow the FO2 operations setting to
be set quicker. Additionally, it is possible to set other FO2
values for the mixture (in increments of 1%) each time you
depress button C ( ). The constant depressing of button C
will increase the increments rapidly.
NOTE: By varying of the mixture’s oxygen percentage, the
computer indicates the maximum depth (MAX) which may
be reached with that mixture, since it depends on the PO2
value set.
• PO2 Mix 2 is the partial pressure of the latter of the two
Nitrox mixtures (MIX2) that can be set on Archimedes II
computer. It is factory set on the value of PO2=1.4, but it may
be changed by the diver on values between 1.0 bar (included)
and 1.6 bar (included), by increments of 0.1 bar, following
each other at each depression of button C ( );
• FO2 Mix 2 is the oxygen percentage of the second Nitrox
mixture (MIX2) set on Archimedes II computer. It is factory
set on Off (FO2= - -%) and it may be switched on only by the
diver, by depressing button C ( ), on values between FO2=Air
(21%) and FO2=99% (pure oxygen), by variations of 1%, fol-
lowing each other at each pressure of button C ( )
• A Safety Factor may be set by the diver at one of three
values (SF0/SF1/SF2). It is factory set at SFO.
WARNING: In order to dive more conservatively, please
change your safety factor any time you feel that you are at
risk of decompression sickness.
• The maximum depth alarm is set on ft. 132 and OFF by the
factory (picture 4 a); it can be switched On and be modified
as well as the depth at which it will start (picture 4b), by
depressing button C ( ).
At the end of the setting, depress button B (Mode) for seve-
ral seconds; this will allow you to return to the normal display
(picture 1).
Related topics:
• 2.5.1. - Maximum depth alarm.
• 3.1. - AIR DIVE.
• 3.2. - NITROX MIXTURES DIVE.
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2.3.2 - Dive planning ( ).
While on the surface it is possible to go to the Plan function
( ) in order to visualize the remaining time available at dif-
ferent depths, without having to make decompression stops
(curve time), only by primary mixture MIX1.
The values are given both for the first of a (possible) series of
dives and during the surface interval between two or more
subsequent dives; in such case, Archimedes II takes into
account the residual nitrogen, therefore reducing the curve
times.
When the computer is set on program, by depressing
button B (Mode) twice, you view to the function ( ), as
shown by the alphanumeric display. The display will show (pic-
ture 5, air; picture 5.1., Nitrox) no decompression depths times
between 30 – 157 ft., in depth increments of 10 ft. This is obtai-
ned by depressing C ( ), or by manual depth decreases, each
of ft. 10, by depressing button A ( ).
Depress button B (Mode) for several seconds in order to get
back to the normal display (picture 1).
NOTE: PLAN function will be switched off in program
and in this case the computer shows Error.
Related topics:
• 2.3.1. - program parameters setting
• 3.4. - Curve dive
• 4.1.1. - Surface interval.
• 3.5.1. - Omitted decompression stage alarm. (Error)
2.3.3. - Rapid visualisation of set data ( ).
The INFO ( ) icon on Archimedes II Cressi-sub computer
UFDS display allows you to visualize, while on the surface,
every set parameter for your dive in a quick and easy manner
(picture 6), when the computer is set on program.
By depressing button A ( ), the computer will display the set
PO2 and the relating maximum depth MAX (given in m or ft.);
the possible setting of a safety factor (SF0/1/2); the possible
oxygen percentage of the primary Nitrox (Mix 1) and the rela-
ting icon ( ), or the icon ( ) in case of an air dive. By
keeping the button depressed, the computer will display the
second mixture’s parameters (if set) in alternative sequel, and
then return to those of the primary.
Related topics:
• 2.3.1. - program parameters setting
• 3.1. - AIR DIVE.
• 3.2. - NITROX MIXTURES DIVE.
2.4. - program parameters setting (deptho-
meter/timer)
The Archimedes II computer is equipped with a third program
( program or depth meter/timer) that may be used for
both apnea (free divers) divers and for the use in technical
dives with helium-based binary and ternary mixtures. In this
case, the instrument gives only the dive’s basic depth and dive
time parameters. It does not make tissue saturation and de-
saturation computation, which must be programmed and
computed by means of proper software and/or tables.
Cressi-sub reminds you that sport dives must be carried out
within the no-decompression guidelines, and at the maximum
depth of 132 ft. This is the limit of sport diving. To exceed these
limits remarkably increases the risk of decompression sickness.
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WARNING: Archimedes II Cressi-sub computer has been
developed for sport diving use only. It is not intended for
commercial or professional use requiring longer dive times
and greater depths. Diving beyond the parameters of sport
diving dramatically increases the risk of decompression
sickness.
 DANGER: Cressi-sub discourages diving with
gaseous mixtures other than air without proper training.
The use of “
technical ” multi-gas mixtures may expose the
diver to different risks than those of sport diving, including
serious physical damages and, in extreme cases, death.
WARNING: After a dive with Archimedes II set in
mod. (depth meter-timer). The instrument will
not make saturation and de-saturation computa-
tions during the following 48 hours.
 DANGER: Should you decide to reset the instrument
by depressing button RESET on the back of the computer,
the nitrogen memory will be cancelled; therefore; the
instrument will not be able to compute a following dive.
Never use this function for at least 48 hours after the last
diving activity.
To go to program depress button B until the menu
is shown, then depress button C, which you may choose
Archimedes II DIVE/GAGE programs (Picture 7).
NOTE: Archimedes II computer is set at the factory on
program.
program will remain set until the diver changes the pro-
gram to be used.
In program, the INFO, PLAN and SIMU functions are swit-
ched off, while it is possible to set only a maximum depth
alarm which may be switched on or off by the user by setting
the instrument, following the same procedures shown in
chapter 2.5.1.
NOTE: In function the depth indicator gives indica-
tions between 0 – 655.8 ft..
Related topics:
• 2.5.1. – Maximum depth alarm.
• 3.6. – program (depthometer/timer)
2.5. - Instrument general setting.
2.5.1. - Maximum depth alarm
Archimedes II computer is equipped with a maximum depth
alarm preset at the factory (picture 8 a) on a value of 132 ft.
This is the limit of sport dives. When the function is on (ON)
(picture 8b), upon reaching the set maximum depth a sound
alarm will start and the display will flash for three seconds.
It is possible to switch on the alarm, or modify the maximum
depth, by depressing button B, then button A ( ), selecting,
in the following order, the dive’s parameters relating to:
PO2 Mix 1 -> FO2 Mix 1 -> PO2 Mix 2 -> FO2 Mix 2
-> Safety Factor -> Max Depth -> OFF/ON
While in Max Depth menu (picture 8 a), you may modify the
value of maximum depth from 0 – 325 ft., by depressing but-
ton C ( ). When you have set the desired depth, depress but-
ton A ( ) in order to switch on or off the depth alarm by means
of button C ( ). The computer is set at the factory on the
values of 132 ft. and OFF. Depressing button B (Mode) for seve-
ral seconds will return back to the normal display (picture 1).
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171
NOTE: When switched on (ON), the maximum depth
alarm works in both and computing programs.
Related topics:
• 2.3.1. – parameters setting.
• 2.4. – program (depthometer/timer)
2.5.2. - Date and time adjustment ( ).
To adjust date and hour, depress button B (Mode) until the
icon ( ) appears on the UFDS display, with the seconds’
display flashing (picture 9).
By depressing button A ( ) view the regulation of (picture
9). 1) second, 2) minutes, 3) hour, 4) 12/24h and, in sequen-
ce, year, month and day. By depressing button A ( ), the
function to be modified will flash and may be varied by
depressing button C ( ).
To revert back to the normal display (picture 1), depress but-
ton B (Mode) for several seconds.
NOTE: Always check the hour and date in order to get
correct entries in your computer’s logbook.
Related topics:
• 4.1.2. – Logbook.
• 3.6. – program (depthometer/timer)
2.5.3. - Units of measure setting.
Archimedes II computer can make computations by metric
units (depth in meters and temperature in °C), or in feet and
(depth in feet and temperature in °F).
To change the units of measure to be used, depress button
B (Mode) to go to the first menu of ( or ) program
setting (picture 3). Then depress buttons A+C in sequence
and keep them pressed together for about 5 seconds. An
alarm and the new set unit of measure will appear on the
display.
By depressing button B (Mode) for several seconds, you will
return to the normal display (picture 1).
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3) While diving
3) While diving
Foto Ghisotti
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173
3. - program.
Archimedes II computer offers two computing pro-
grams; for air ( program) and for nitrox mixtures or
EAN (Enriched Air Nitrox) dives. Archimedes II allows for use
with up to two different nitrox mixtures during the same dive.
NOTE: Archimedes II computer is set at the factory on
program, with the primary mixture’s (Mix 1) O2
value on 21% and PO2 on 1.4. The second mixture (Mix
2) is set at the factory off. Each manual variation of the
manufacturer’s values relating to Air program will start
Archimedes II Nitrox computation program.
3.1. - AIR DIVE.
Archimedes II computer starts automatically the "Dive" pro-
gram at a depth superior to (ft. 5). During a curve dive the
display will show the following information (picture 10):
1 current depth value, in meters (m) or feet (ft.)
2 no decompression time still available is shown by the
“NDL” - (No Decompression Limit) icon
3 maximum depth reached during the dive
displayed in meters (m) or in feet (ft.), shown by the
“MAX” icon
4 time spent diving, shown by the "DIVE T" icon
indicator of segmented surfacing speed
6 graph of nitrogen amount absorbed during the dive
7 graph representing CNS O2 toxicity level (see chapter
3.3.4)
8 Automatic indicator of altitude level
9 Icon of maximum depth alarm (if switched ON – see 2.5.1)
10 indicator of Nitrox mixture(s) dive
11 MIX1 or MIX2 icons identifies which Nitrox mixture is being
considered by the computer to make its computations
12 ( ) and ( ) icons, that is “Info” (button A) and back-illu-
mination (button C).
Further important information are obtained by keeping pres-
sed button A ( ) during the dive, that is (picture 11):
1 current PO2;
2 oxygen percentage of the selected mixture (Air if FO2=21%);
3 maximum depth reached during the dive, in meters (m) or
feet (ft.);
4 current temperature, expressed in °C or °F
The UFDS display show ( ).
NOTE: When the computer is used for air dives, it is not
necessary to carry out any FO2 change or setting before
the following dive.
During your diving activity, light condition may not allow easy
reading of the display, therefore, it is possible to switch on its
back-illumination by depressing button C ( ). The display’s
back-illumination will last about 5 seconds and may be repea-
ted any time you want. The battery consumption is minimal
when the back-illumination is activated.
Related topics:
• 2.3. – Dive parameters setting
• 3.4.1. – Ascent rate.
• 3.3.3. - Mixture changing by diving
• 3.3.4 - CNS toxicity display.
• 3.3.5. - PO2 alarm.
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3.2. - HYPER-OXYGENATED (NITROX) MIXTURES
DIVE
3.2.1. - Before a Nitrox dive.
 DANGER: the use of the computer with hyper-oxyge-
nated (Nitrox) mixtures is exclusively intended for divers
who have attended a full training course on the use of
such mixtures.
The Nitrox program for Archimedes II computer allows
making saturation and de-saturation computations for a dive
by using up to two different nitrox mixtures and is switched on
any time the parameters of program the primary
mixture FO2 on Mix1=21% and second mixture Mix2=off, are
changed. In this case the display will show (Nitrox) icon (pictu-
re 12) which will stay on during the dive and until Archimedes II
remains set on Nitrox parameters.
Once Nitrox program is on, it is necessary to set Archimedes II
computer with the exact values of oxygen percentage (FO2)
contained in the cylinders to be used during the dive, after
having analyzed their content, so the computer is able to adapt
its computing algorithm according to the new set parameters.
WARNING: Archimedes II computer always keeps
program switched on for air dives, until the diver
sets it for the use with Nitrox mixtures (chapter 2.3.1– Dive
parameters setting)
 DANGER: Do not dive with cylinders containing Nitrox
mixtures without checking their oxygen percentage.
WARNING: Before diving, always check the oxygen per-
centage of the mixture(s) set on the computer. This is done
on surface by depressing button A ( ) which allows visua-
lization of the previously set parameters.
WARNING: Under the same dive conditions, a Nitrox mix-
ture requires longer no decompression times than air. It is
recommended to comply with the maximum depth allowed
by the selected Nitrox mixture.
Related topics:
• 2.3.1. - parameters setting.
• 2.3.3. - Rapid visualization of set data.
• 3.3. - Nitrox parameters setting.
• 3.3.3. - Mixture changing by diving.
• 3.3.4. - CNS toxicity display.
• 3.3.5. - PO2 alarm.
3.3. - Nitrox parameters setting.
3.3.1. - Partial pressure setting (PO2).
Archimedes II is set at the factory on a basic PO2 value of 1.4
bar for both mixtures of Nitrox and air dives, in order to gua-
rantee the maximum safety during dives.
It is possible to modify the PO2 setting on values between 1.0
bar and 1.6 bar. Should you elect to increase the dive’s margin
of safety, it is possible to set PO2 on lower values, down to a
minimum of 1.0 bar. It is explained in paragraph 2.3. how to
carry out the selection of values. To do so, depress the central
button B (Mode) to the ( ) menu, shown in picture 3, and
the parameters will be modified according to the following
scheme: by depressing button A ( ) it is possible to select, in
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175
the following order, the dive parameters relating to:
PO2 Mix 1 -> FO2 Mix 1 -> PO2 Mix 2 -> FO2 Mix 2
-> Safety Factor -> Max Depth -> OFF/ON
where PO2 Mix 1 is the oxygen’s partial pressure of the primary
mixture (MIX1), which the diver may set, as already shown, on
values between 1.0 bar and 1.6 bar, by variations of 0.1 bar. The
same may be done for the second mixture’s (Mix 2) PO2. By
depressing button A ( ) the chosen setting is confirmed.
To return to the normal display depress button B (Mode) for
several seconds (picture 1).
WARNING: The computer keeps the PO2 setting on, until
the diver manually resets it to different values.
Related topics:
• 2.3.1. - Dive parameters setting
• 3.3.3. - Mixture changing by diving.
• 3.3.4. - CNS toxicity display.
• 3.3.5. - PO2 alarm
3.3.2. - Nitrox mixture(s) oxygen fraction FO2 setting.
WARNING: Check the FO2 value set on the computer prior
to diving!
In order to set the correct oxygen percentage contained in the
Nitrox mixture(s), depress the central button B (Mode) to the
(DIVE)menu, asshown inpicture 3, where the parametersmay be
modifiedaccording to thefollowing scheme:by depressing button
A ( ) it is possible to select the dive parameters relating to:
PO2 Mix 1 -> FO2 Mix 1 -> PO2 Mix 2 -> FO2 Mix 2
-> Safety Factor -> Max Depth -> OFF/ON
where FO2 Mix 1 is the oxygen percentage of Nitrox primary
mixture (MIX1), which can be set on values between 21% and
50%, by O2 variations of 1%. The second mixture’s FO2 (FO2
Mix2) can be set to values between 21% and 99%, by O2 varia-
tions of 1%. This is done by depressing and keeping button C
( ) depressed.
NOTE: By keeping button C ( ) depressed, the computer
automatically stops on the value of the first of the two standard
Nitrox mixtures (EAN 32), corresponding to 32% oxygen.
NOTE: By varying the oxygen mixture percentage, the
computer will display the maximum depth (MAX) that may
be reached with that mixture.
This depth varies according to the set PO2.
Depress button C ( ) to manually set percentages of other
mixtures different from the standard ones.
Depress button A ( ) in order to confirm the desired percen-
tage, which will appear on the display.
Depress button B (Mode) for several seconds to return to
the normal display (picture 1).
NOTE: It is possible to modify the Nitrox mixture(s) setting
even during the surface interval (
with de-saturation in pro-
gress ) (Picture 12a).
This feature is important, especially for divers who carry out a
series of subsequent dives; it allows the modification of one
mixture after having carried out a first air dive without having
to wait until full de-saturation.
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176
It is important to comply with and understand the following:
1 At the end of a dive, the previously set mixture(s) oxygen
percentage FO2 will be stored in the memory
only during
the first ten minutes of the surface interval. Should
another dive be carried out within this period of time, it will
be interpreted by the computer as a continuation of the
previous dive.
NOTE: It is not possible to go to program within the
first 10 minutes after having ended a dive.
NOTE: It is NOT possible to set any variation of the mixture(s)
FO2 within the first 10 minutes after having ended a dive.
Additionally, it is not possible to get to the (DIVE) parameters
setting menu and therefore to modify the previously set per-
centage, within the first 10 minutes of surface interval.
2 10 minutes after the completion of the dive, the computer
resets the FO2 percentage/s on a safety value of 99%, wai-
ting for the user to set the correct value relating to the new
mixture(s). The display will show "--" as in (picture 12b).
The diver must analyze the following dive’s mixture and set
the new FO2 value on the computer.
Should you neglect to set the new FO2 value on the compu-
ter, you would be warned by the PO2 alarm (picture 13), at a
depth of m 4 (ft. 13) (toxicity limit of a EAN 99 mixture, with
P02 value set on 1.4), the FO2 automatically resets the O2
limit value of 99%. This is done to warn the diver and correc-
tly reset his dive’s parameters, by surfacing at once. Should
the dive be continued, a second PO2 alarm at 1.6 bar (that is
at 20 ft.) would start.
3 Should the FO2 value be set and no dive carried out, the
computer will store the set value in the memory until the
current day’s midnight, when it will reset it on 99%
(picture 12b)
Related topics:
• 2.3.1. - parameters setting
• 3.3.1. - PO2 setting
• 3.3.4. - CNS toxicity display.
• 3.3.5. - PO2 alarms
• 4.1.1. - Surface interval.
3.3.3. - Mixture changing while diving.
Archimedes II computer can make computations relating to
the saturation and de-saturation of a dive carried out using up
to two nitrox mixtures. In the previous chapters, it has been
shown how to set the basic PO2 and FO2 parameters of the
primary mixture MIX1 and the (possible) second mixture
MIX2, before the dive.
NOTE: Archimedes II computer always starts the computa-
tions relating to the dive on the primary mixture MIX 1.
While diving, it is possible to change from the primary mixtu-
re MIX1 to the second mixture MIX2, by depressing button
B for more than 5 seconds, until the icon of the new mixtu-
re stops flashing. At this point, the mixture change will be
shown by the new value, shown by the MIX2 icon, on the
UFDS display (pictures 14a and 14b).
The same procedure may be used to carry out the opposi-
te change; this will change to the primary mixture MIX1,
when the computer is set on the second mixture MIX2.
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177
 DANGER: As a safety measure, in order to avoid the
involuntary setting of nitrox mixtures at depths where they
might be toxic (excessive PO2), Archimedes II does not
allow the mixture change if the new mixture’s PO2 is higher
than the one set on the computer (1.4 bar = default value).
The maximum PO2 alarm will sound if you attempt to set
nitrox mixtures at depth.
 DANGER: Should both mixtures’ FO2 values be set and
no dive carried out, the computer will store the set values in
the memory until the current day’s midnight, when they
both will be reset on a value of 99%.
 DANGER: After 10 minutes from the end of a dive, the
computer resets the mixtures’ FO2 on a safety value of
99%, waiting for the user to set the correct values relating to
the new mixtures. The display will show "--" in the place of
FO2%, as in (picture 12b).
 DANGER: Always check, prior to diving, the FO2 and
PO2 values of both set mixtures! While on the surface, it is
possible to check their values, by depressing button A ( ),
which visualizes the previously set parameters.
 DANGER: do not dive with bottles containing Nitrox
mixtures, without having personally checked their oxygen
percentage.
Related topics:
• 2.3.1. - program parameters setting
• 3.3.1. - PO2 setting
• 3.3.2. - Nitrox mixture/s oxygen fraction F02 setting
• 3.3.4. - CNS toxicity display.
• 3.3.5. - PO2 alarms.
3.3.4. - CNS toxicity display
Archimedes II computer is display a graph of the Central
Nervous System toxicity level as to the oxygen level. Its toxi-
city level is bound with the oxygen’s partial pressure and
with the exposure to high oxygen partial pressures (PO2).
Picture 15 represents the UFDS display’s 8 pixels column,
which shows the increasing accumulated oxygen quanti-
ties. When all 8 pixels light up, 100% of the maximum tole-
rance allowable to the CNS has occurred and serious dan-
ger of an oxygen intoxication exists.
It is important to understand, monitor, and control the oxy-
gen toxicity level.
In order to reduce the risk of oxygen toxicity, Archimedes II
displays a graph which is easy to be read in any situation.
When the oxygen level reaches warning values, next to the
maximum allowable toxicity (corresponding to 7 of 8 lighted
pixels), the graph starts flashing along with the display, and
an alarm starts sounding which lasts 15 seconds, showing
the proximity of a CNS toxicity level.
When the eighth pixel lights up, a second (100%) alarm
starts sounding. At this time the graph and display flash and
the alarm sounds, until the diver surfaces, letting the oxygen
partial pressure decrease.
When the eighth pixel turns off and the graph stops flashing,
the alarm will be entered in the Logbook.
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