User`s manual

211

Of course, the diver must analyze the subsequent dive‘s mixtu-

re and set the computer with the new FO2 value.

Should you neglect to set the new FO2 percentage on the

computer, you would be warned by the PO2 alarm (picture 15),

at a depth of only 13 ft. (toxicity limit of an EAN 99% mixture, with

PO2 set on 1.4). This is done to warn the diver and get him to

correctly 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 the safety

value of FO2 = 99%. The dive’s parameters setting will

change as shown in picture 14.

Related topics:

• 2.4.1. - DIVE program parameters setting

• 3.3.1 - Partial pressure setting (PO2)

• 3.3.3. - CNS toxicity display (OLI).

• 3.3.4. - PO2 alarms.

• 4.1.1. - Surface interval after a DIVE program

3.3.3. – CNS toxicity display

Cressi sub computer displays a graph of the oxygen

toxicity level to the Central Nervous System (CNS). The toxicity

level depends on the oxygen partial pressure and on the expo-

sure to high oxygen partial pressures (PO2). Picture 16 repre-

sents the display’s 8 pixels column which shows the increasing

accumulated oxygen amount. When all 8 pixels light up, 100%

of the maximum tolerance allowable to the CNS has occurred

and serious danger of an oxygen intoxication exists.

It is important therefore to understand, monitor and control

the oxygen toxicity level.

In order to reduce the risk of oxygen intoxication,

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 as well, a second (100%)

alarm starts: the graph and display start flashing and an alarm

starts sounding, as long as the diver does not surface, and

the oxygen partial pressure does not decrease. Only when

the eighth pixel turns off, the graph stops flashing, while the

alarm will be entered in the Logbook.

NOTE: The result of the oxygen exposure computations

is approximated to the above percentage value.