MARES CXR-I : How-To Guide : Page 14

9.8.

VIEWING MAPS DURING A DIVE

module,

the

screen

shows the tank

pr

es

sure

as well (Fig. 31).

If you

submerge

again

before

the

3-minut

e

countdown

is over, the dive time will

r

esume

from

where

it left off, including the time

spent

on

the

surface.

If you do not

submerge

bef

or

e

the

end of the

countdown,

CXR-I

considers

the

dive finished,

records

the data to the

logbook

and

r

e

v

erts

to the

so-called

post-dive

mode.

The

post-dive screen

shows the

f

ollowing

information

(Fig. 32):

•

11.

DIVING WITH MORE THAN

ONE

GAS

MIXTURE

To call up the map

selected under

SET

DIVE/LINKED MAP

,

press

from

the

decompression summary table.

The map will

remain

on the display for 10

seconds,

aft

er

which the

screen

r

e

v

erts

to dive inf

ormation.

Y

ou

can

press

to

return

to the main

scr

een

before

the 10

seconds

have

elapsed

(Fig. 29).

-

The

remaining desaturation

time (DESAT):

this is

calculated

by the

decompr

es

sion

model in the

computer.

Any

dive

s

tart

ed

while

there

is

remaining desaturation on

your

computer

is

considered

a

r

epetitiv

e

dive,

meaning

that CXR-I

accounts

for

the

pre-existing nitrogen

load in your body

.

The no-fly time

(NO-FLY TIME)

:

this

is

the time during which an

exposure

t

o

the

reduced pressure

inside the cabin of

an

airplane

could

cause

decompr

es

sion

sickness.

CXR-I

employs,

as

r

ec

ommended

by

NOAA, DAN

and

other agencies,

a

standard 12-hour (no-deco

non-r

epetitiv

e

dives) or

24-hour

(deco and

repetitive

div

es)

countdo

wn.

9.9.

UNDERWATER

MENU

By

pressing

and holding the left button ( )

y

ou

can call up a

menu

which allows you to

change

certain settings

during the dive. These

are

described

in detail in

section

2

although

some

names

have

changed

a bit due to the

limit

ed

length available

in the

UW

menu

(Fig. 30).

BOOKMARK

-

allows you to set a

bookmark

which you can

later review

in the

downl

oaded

dive

pr

ofil

e

AIR

(or G1)

- corresponds

to

MODE

in 2.1.

This

is

meant

for

those occasions

when you

f

or

got

to

update

the oxygen

percentage setting

in

the

computer

after a

change

of nitrox, a

switch

from air to nitrox or

vic

e

v

er

sa,

which w

ould

force you to abort the dive or at

least

go to

the

surface,

wait

three minutes

to exit the dive

and

then

perform

the

change.

This

menu

is

activ

e

only during the

first minute

of the dive and

onl

y

if the depth has not

exceeded

6m

/ 20ft.

-

CXR-I

enables

you to use up to

three gas

mixtures

during the dive (air and

Nitr

o

x

only). The

three mixtures

are

labeled

G1, G2

and

G3

and

must

be in

ascending order of

oxygen

content,

i.e.

G1

has the lowest

oxygen

concentration,

G2

an

intermediate

value,

and

G3

has the

highest

oxygen

concentration

of

the

three.

Two or more

tanks

can also be set to

the

same

oxygen

concentration.

If you are diving

with only two

mixtures,

you will be

utilizing

tanks

G1

and G2.

CXR-I can be set to

consider

all active

gases

in the

decompression calculation,

or it

c

an

be set to

consider

only the gas

curr

entl

y

in

use. In the

first case

(

PREDICTIVE

=

ON

in

2.5.1), when you switch gas when

pr

ompt

ed

to do so during an

ascent,

you will not

see

a

change

in the

decompression

c

al

culation:

CXR-I

considered

that you were going

t

o

switch gas and

already considered

the

eff

ect

of this on the

decompression.

In the

sec

ond

case

(

PREDICTIVE

=

OFF

in 2.5.1) you will

see

a

reduction

in the total

ascent

time as

y

ou

switch to a gas with

higher

oxygen

content and

CXR-I

considers

this for the

decompr

es

sion

c

al

culation.

CXR-I can show the tank

pressure

of

each

tank if the

corresponding first stage

r

egulator

is

equipped

with a Mares tank

module,

paired

as

described

in

section

1.8. Note that

CXR-I

can be

programmed

and used for diving

with

more than one gas

mixture whether

you

use

tank

modules

for each or

not.

The

DESAT TIME

could be

shorter

than

the

NO-FL

Y

TIME,

which would imply that

y

ou

cannot

fly

although

you are

desaturated.

This

is

simply the

consequence

of the

desatur

ation

time being

calculated

by the

algorithm

based

on the

actual

dive profile, while the no-fly

time

is an

accepted standard

in the diving

industry.

Since the

real

effect of flying after diving

has

never been fully

investigated,

this

approach fits

with our

philosophy

.

-

The

surface

interval

(SURF. INT.)

:

this

is

displayed

from the

moment

the dive

is

closed

(3

minutes

after

surfacing)

for

as

long as

there

is

remaining

desaturation or

no-fly time on the

comput

er

.

CNS: this allows you to track how the CNS

load from the

gr

aduall

y

reduced

during the

surface

interv

al.

GF

DIVE

-

as

described

in

2.2.3

LINKED MAP

-

as

described

in

2.12

NIGHT MODE

-

as

described

in

2.8

FUTURE DECO

-

as

described

in

2.6

MAX

DEPTH

-

as

described

in

2.4.1

DIVE TIME

-

as

described

in

2.4.2

BRIGHTNESS

-

as

described

in

3.4

TANK VOLUME

-

as

described

in

2.3

MAX

PRESSURE

- corresponds

to

OPERA

TING

TANK

PRESSURE in

2.3

HALF TANK

- corresponds

to

MID TANK

WARNING

in

2.3

TANK RESERVE

-

as

described

in

2.3

WATER

-

as

described

in

2.7

-

The

screen

also shows the main data of

the

last dive: max depth,

temperature,

dive

time,

initial and final tank

pr

es

sur

e.

In addition, the

supersaturation

with

respect

t

o

ambient pressure

at the

surface

in all

16

compartments

of the

algorithm

is

sho

wn

discretized

in ten

segments.

The

tallest

bar

is

also

reproduced

along the left edge in the

same

fashion as it is also during the dive.

Y

ou

c

an

use this to

gauge

your

progress

in

getting

rid of

nitrogen

as the

surface

interval grows.

CXR-I

continues

to

perform decompr

es

sion-relat

ed

calculations

(inert gas

release),

for as long

as

there

is

desaturation

or no-fly time

l

eft.

•

10.

AFTER THE

DIVE

Upon

returning

to the

surface,

CXR-I

fi

rst

goes into the

so-called

surfacing mode.

This

mode allows you to

resume

your dive after

a

brief period of

orientation.

The

screen

sho

ws

a

3-minute countdown,

a profile of the dive,

your

maximum

depth, dive time,

average depth

and, for nitrox dives, the CNS% at the end of

the dive. When used with the optional

t

ank

11.1.

SETTING MORE THAN ONE

G

AS

The

characteristics

of the

gases must be

entered

in the

computer before

the dive. It will

then be your

responsibility

to tell CXR-I

which

gas is

curr

entl

y

being used during the

v

arious

phases

of the

div

e.

15

NOTE

Y

ou

can set all the

gases

to the

same

oxygen

per

c

ent

age.

NOTE

This

menu

is not

meant

for

switching

to

a

high oxygen

content decompression

gas.

W

ARNING

Flying while CXR-I

displays

NO-FLY

c

an

result

in

serious

injury or

death.

NOTE

-

In the event of an

alarm, CXR-I

aut

omatic

all

y

switches

back to

the

standard

display

.

-

The map is

static,

and does not

change

as you swim during the

div

e.

W

ARNING

-

Diving with more than one gas

mixtur

e

represents

a much

higher

risk

than

diving with a single gas

mixture, and

mistakes

by the diver may lead

t

o

serious

injury or

death.

-

During dives with more than one

gas

mixture,

always make

sure

you

are

breathing

from the tank that you

int

end

to

breathe

from.

Breathing

from a

high

oxygen

concentration

mix at the

wrong

depth can kill you

ins

t

antl

y

.

-

Mark all your

regulators

and

tanks so

that you

cannot confuse

them

under any

cir

cums

t

anc

e.

-

Before each dive and after

changing

a

tank,

ensure

that each gas

mixtur

e

is set to the

correct

value for

the

corresponding

t

ank.