How-To Guide

• 2. SET DIVE
2.1. MODE
In this menu you define the type of gas you will
be breathing during the dive ( AIR as SINGLE
GAS, NITROX as SINGLE GAS, NITROX as
MULTIGAS, TRIMIX as MULTIGAS ). Y ou
can also set CXR-I to BOTTOM TIMER , in
which case CXR-I will show only time, depth
and temperature: it will not carry out any
decompression calculation and it will not sho w
any warnings and alarms.
Use and to highlight your choic e,
then press SELECT to activate it. AIR is the
equivalent of setting NITROX to 21% and a
ppO max of 1.4bar.
2
When selecting NITROX , you are taken to a
submenu in which you can define the
percentage of oxygen in the mixture (O %) and
2
the maximum value of oxygen partial pr es sure
(ppO max) for up to three breathing mixes. The
2
maximum possible value for the ppO max is
2.2. ALGORITHM
CXR-I employs the unmodified Bühlmann ZH-
L16C algorithm with gradient f act or s. Gradient
f act or s are used to lower the maximum
tolerated supersaturation in the tissues with
respect to Bühlmann’s original v alues. This
results in less nitrogen in the body at the end of
the dive, which under normal circumstances
makes the dive safer. Gr adient f act or s are
expressed in pairs: the first v alue, also called
GF low, represents the per c entage of the
original Bühlmann value that defines the
beginning of the final ascent (r el e v ant only in
decompression dives); the second value, also
called GF high, represents the percentage of
the original Bühlmann value that defines the
residual nitrogen at the surface at the end of
a dive. As an example GF 50/85 will get you t o
the surface with a 15% additional margin with
respect to Bühlmann’s original maximum
tolerated supersaturation and, if this was a
decompression dive, your first decompr es sion
stop would have been at a depth such that y ou
would not have exceeded 50% of Bühlmann’ s
original value at that depth.
For more information about gradient f act or s,
please refer t o
www .mares.c om /sports/diving/gr adientf act or
From the home display, press and hold the
third button from the left ( GF ) to display a t abl e
listing all settings (Fig. 6).
MENU
Descrip tion
SET DIVE
Allows you to choose
between air, nitrox, trimix and
bottom timer mode.
MODE
Allows you to set main and
alternate gradient f act or s,
personalization levels, and
mor e.
AL GORITHM
Allows you to synchr onize
your CXR-I with optional
tank modules and to define
all parameters conc erning
gas integration (tank v olume,
operating tank pressure, t ank
reserve and mor e).
GAS
INTEGRA TIO
N
Allows you to define and
activate certain warnings
individuall y .
2
1.6bar. Most training agencies r ec
to exceed a value of 1.4bar.
ommend not
W ARNINGS
Once inside this menu, use
and to change
Allows you to define
parameters relating t o
multigas div es.
the O %, and watch how this affects the
maximum operating depth (MOD). Then pr es s
NEXT to move on to the ppO max and use
2
MUL TIG AS
2
and to change the value, again noticing
how this affects the MOD. Press SET to sav e
and exit the menu. Note that you can pr es s
BACK after having set the O % to save and e xit
2
skipping the ppO max setting.
2
Allows you to set the
parameters for the futur e
dec o prediction. Please r ef er
to section 2.6 for more det ails
on this.
FUTURE
DECO
2.2.1. MAIN GF
This is where you set the conservatism l e v el
of the ZH-L16C algorithm via gradient f act or s.
We use Bühlmann’s original values reduced by
15% as a starting point, and you can make the
algorithm more conservative from there. Ther e
are four predefined sets of gradient f act or s
with increasing conservatism from R0 (85/85)
to R3 (50/60) for recreational dives and from
T0 (30/85) to T3 (25/40) for tech dives. Y ou
can also enter the GF low and GF high v alues
directly via the CUSTOM setting. The def ault
value is R0 (85/85).
Allows you to choose
between salt and fresh wat er .
W A TER
Allows you to choose the night
mode display (white number s
on black background) as
default display .
NIGHT MODE
Allows you to activate or
deactivate the visualization of
deep s t ops.
DEEP STOP
Allows you to choose the
depth of the shallowest s t op
among 3m/10ft, 4.5m/15ft,
6m/20ft.
DECO STOP
2.2.2. ALTERNATE GF (TO BE INTRODUCED
VIA FREE FIRMWARE UPGRADE SOON)
CXR-I allows you to define an alternate set
of gradient f act or s, to use when you need
to cut your decompression short in case of
an emergency. The set of alternate gr adient
f act or s cannot be more conservative (i.e.
lower) than the main set of GF v alues. The
default value is R0 (85/85).
This is also the menu where you would be
setting your decompression gases if you div ed
with more than one gas. See chapter 11 f or
more information about diving with more than
one gas or for dives with trimix.
Allows you to show the div e
time in minutes and sec onds.
SECONDS
Allows you to select a map
which you can call up on the
display during the div e.
LINKED MAP
Allows you to reset the
inert gas saturation to zer o,
thereby erasing the effects of
a previous dive. This is only f or
people who plan to lend their
computer to another div er
who has not performed a div e
within the last 24 hour s.
ERASE
DESAT
ALL SILENT
MODE
Allows you to silence the div e
comput er .
Allows you to turn off the div e
violation due to unc ontr oll ed
ascent. This is for div e
instructors only, who may
find themsel v es in such a
situation because of their
teaching r equir ements.
ASCENT
VIOLA TION
7
W ARNING
- Diving with Nitrox may only be
attempted by experienced divers aft er
proper training from an int ernationall y
recognized agency.
- Before every dive and after changing the
tank, you must make sure that the set
oxygen concentration in CXR-I
corresponds to the oxygen conc entr ation
in the tank. Setting the wrong oxygen
concentration can lead to serious injury
or death.