MARES CXR-I : How-To Guide : Page 15

CXR-I

Dive

Comput

er

switch

screen appear,

which shows all

activ

e

gases

(Fig. 35).

11.4.

DIVING WITH MORE

THAN

ONE GAS MIXTURE

-

TRIMIX

OR HELIOX (TO

BE

INTRODUCED VIA

FREE

FIRMWARE UPGRADE

SOON)

CXR-I allows you to set up to 5

gases

in

which

in

addition to the oxygen

percentage

you

c

an

also

set the

helium percentage.

In the

tis

sue

saturation graph

you will see

bars

for

the

nitrogen partial pressure

and for the

helium

partial pressure.

Everything else is the

same

as

with

multigas

nitrox diving with the addition of

OTUs (Oxygen Toxicity Units) in the

sequence.

Press

to scroll

through

the

available

gases,

then

press

to

activate

it. The

decompr

es

sion

calculation

will

reflect

the switch in

br

eathing

gas. In addition, the display will now

sho

w

the symbol of the new gas and its

oxygen

concentration.

In profile view, the

area

bel

o

w

the

MOD

of the deco gas is

depicted

in

r

ed.

•

12.

BOTTOM TIMER

MODE

When CXR-I is set to

BOTTOM TIMER

mode,

it will only

monitor

depth, time, tank

pr

es

sure

and

temperature,

and will not carry out

any

decompression calculation.

Y

ou

can

onl

y

switch to bottom timer mode if the

computer is

compl

et

el

y

desaturated.

All

audible

and

visual

alarms, other

than the low

battery alarm,

are

turned

off

.

-

Y

ou

can

select another

gas using , if

To use

multiple gases,

you will need to

enabl

e

the

gases

and set the oxygen

per

c

entage

and the ppO max for each one, as

described

2

in Figure 33. Keep in mind that the

MOD

f

or

G2

and

G3

is the depth at which CXR-I will

prompt

you to

perform

the gas switch

(see

section

11.2

bel

o

w).

11.3.

SPECIAL SITUATIONS

11.3.1.

SWITCHING BACK TO

A

G

AS

MIXTURE WITH LOWER

OXY

GEN

CONCENTRATION

There may be

situations

in which you have t

o

switch back to a gas with lower

oxygen

concentration

than what you are

curr

entl

y

breathing.

This can

happen

for

instance

if

y

ou

want to

descend deeper

than the

MOD

for

the

current

gas, or if for

instance

you have run

out

of gas in G3 during the

decompression.

To

do

so, simply

press

and hold to call up the

gas

switch

screen.

Use to

choose another gas,

then

press

to

activate

it. The

decompr

es

sion

calculation

will

reflect

the switch in

br

eathing

gas.

11.2.

SWITCHING

G

AS

During Nitrox dives with the gas

switching

function

enabled,

the third button from the

l

eft

has two

functions, indicated

by a double ic

on:

•

Press: scrolls through

the

sequence of

During a dive in

gauge

mode, the

f

ollowing

information

is

displayed

(Fig. 36):

-

current depth

max

depth

average depth

s

t

opwatch

dive

time

t

emperatur

e

time of

day

battery

s

tatus

tank

pr

es

sure

in

case

of an

ascent: ascent speed

(in

m/min

or

ft/min).

information

to the right of the dive

time

• Press

and hold:

displays

the gas

switch

screen .

CXR-I always

begins

the dive with

G1

, which

has the lowest

percentage

of

oxygen.

When

during the

ascent

you

reach

the

depth

.

corresponding

to the

MOD

of

G2

,

CXR-I

sounds

an

audible

signal and

displays

the

message

SWITCH TO GAS G2

below the top

row

(Fig.

34). The left button now has label

NO

whil

e

the

second

and the third button have label OK.

Press

or

press

and hold

either

of the

OK

buttons

to

perform

the switch, at which point

CXR-I

shortly

displays

the

message

GAS SWITCH

OK;

press

or

press

and hold the

NO

button to

stay on

the

current

gas, at which point CXR-I

shortl

y

displays

the

message

GAS NOT SWITCHED

.

If

you don’t

perform

any action within 30

sec

onds,

CXR-I shows

GAS NOT SWITCHED

and

r

eturns

to the

normal

display. If set to

PREDICTIVE

=

ON

and the gas was not

switched,

CXR-I will

show the

message

EXCLUDING GAS G2

prior

to

changing

the

decompression calculation

t

o

reflect

the

exclusion

of G2.

If you drop again below the

MOD

for G2,

CXR-I

will show the

message

INCLUDING

G

AS

G2 AGAIN

and

changes

the

decompr

es

sion

calculation

ac

c

or

dingl

y

.

11.3.2.

SUBMERGING BELOW THE

MOD

AFTER

A

GAS

SWITCH

If after having

switched

to a gas

mixture

with

a

higher

oxygen

concentration

you

inadv

ert

entl

y

drop again below the

MOD

for that

mixtur

e,

the

MOD

alarm

will

immediat

el

y

go off.

Either

switch back to a gas

mixture suited

for

that

depth, or

ascend

above the

MOD

for the

gas

mixture

you are

breathing

from.

The

stop

watch is

reset

by

means

of .

Upon

pressing

and holding the

same button,

the

gas

switch display is called up. The only

result of

switching

gas

mixtures

in bottom timer

mode

is that the

pressure

of the newly

chosen

tank

is

displayed instead

of the

current one.

11.3.3.

RGT WHEN DIVING WITH MORE

THAN

ONE GAS

MIXTURE

CXR-I

determines

the

RGT

based

on

y

our

breathing pattern,

the tank

pressure

for

the

gas you are

curr

entl

y

breathing,

and

the

decompression

time

calculated

for that

gas

only. It does not

account

for

tanks other than

what you are

curr

entl

y

breathing

from,

henc

e

your

actual autonomy

may be

higher.

For

this

reason

when diving with more than one

gas

mixture

the

RGT

= 3 min is a soft warning

and

not an

alarm.

12.1.

DIVE VIOLATION

INDUCED

BOTTOM TIMER MODE

The following violations can occur during

an

Air, Nitrox or Trimix

div

e:

-

Ascent

violation.

-

Missed deco

stop violation.

In

case

of a violation, CXR-I will

restrict the

use

for 24

hours,

and will only allow

oper

ation

in Bottom Timer mode,

continuousl

y

displaying

the

message

LOCKED BY PREVIOUS

DIVE.

11.3.4.

LOGBOOK FOR DIVES WITH MORE

THAN ONE GAS

MIXTURE

For dives

carried

out with more than one

gas

mixture,

CXR-I adds

information

on

oxygen

concentration,

initial, final and

diff

er

ential

pressure

for all

gases used.

On the dive

pr

ofil

e,

switch points are shown on the time

line.

Y

ou

can always

perform

a

manual

switch, by

pressing

and holding . This will make the

gas

16

NOTE

The

same process

is

repeated

when

y

ou

approach

the

MOD

for G3 with the

message

SWITCH TO GAS

G3

W

ARNING

Dives in

gauge

mode are

performed

at

y

our

own risk. After a dive in bottom timer

mode

you

must

wait at

least

24

hours

bef

or

e

diving using a

decompression

comput

er

.

NOTE

permitted

at that

depth.

-

Y

ou

can exit this mode without

changing

the gas by

pressing .

-

If

there

is only one gas set, the

comput

er

will not

enter

this

menu.

NOTE

Y

ou

can

reach

this

screen

at any

time

during the dive, for

instance

to check

on

the tank

pressure

and the

planned

switch

point of

G2

and G3.

NOTE

-

If you dive using just one gas,

select

G1

and

deselect

the

other

two.

-

For dives with two

gases, select

G1

and

G2

and

deselect

the

thir

d.

-

When

enabling

G2

and G3, you

must

fir

s

t

define

G2

and then G3.

-

Y

ou

cannot activate

G3

without

fir

s

t

having

activated

G2.

-

G2

cannot

have an oxygen

per

c

entage

higher

than G3.

-

If you set

G2

to

OFF

,

G3

will

aut

omatic

all

y

be set to

OFF

also.

-

The

MOD

for

G2

and

G3

is the

switch

depth for the

corresponding

gas.

This

is what CXR-I

uses

for its

c

al

culation,

alarms

and

suggested

switch

points.

-

Setting a tank to

OFF

does not affect

the

pairing of the

corresponding

tank

modul

e.