User`s guide

Nemo Excel dive computer
12
At the same time as the audible alarm is
triggered, the computer begins monitoring an
“Uncontrolled Ascent”. An ascent is considered
“uncontrolled” when the diver exceeds the
maximum rate for a stretch equal to at least
two thirds of the depth at which the audible
alarm was triggered. This criterion only
applies to alarms triggered below a depth of
12 m (39 ft). In case of an uncontrolled ascent,
on surfacing Nemo Excel disables the Air and
Nitrox functions of Dive Mode, and will only
function as a timer and depth gauge (BT). The
other operating modes remain active (fig. 31).
The “Stop” on uncontrolled ascent function can
be disabled in Set Dive mode.
Fig. 31
SAFETY STOP
If the maximum depth of a dive exceeds
10 meters, a “Safety Stop” is activated
for the ascent. In this case Nemo Excel
prompts for a 3 minute safety stop, at a depth
between 2.5 and 6 m (8 - 19 ft), displaying
the “SAFESTOP” message until the stop has
been completed. If the diver moves outside
the above mentioned depth range, the safety
stop timer is halted. When the diver re-enters
the correct depth range, the safety stop timer
resumes from where it left off. If the diver
returns to a depth below 10 m (32 ft), the safety
stop timer will ignore the previously aborted
stop and subsequently start counting down
from 3 minutes again.
In the case of a decompression-stop dive,
the safety stop extends the duration of the
decompression stop at 3 m (10 ft) by an
additional 3 minutes, displaying the safety stop
information as described previously (fig. 32).
Fig. 32

WARNING
Disabling the “Stop” on uncontrolled
ascent should only be done by highly
experienced divers, who take full
responsibility for the consequences of this
action.
SURFACING  AIR
When the measured depth is less than 1 m
(3 ft), Nemo Excel considers the dive to be
suspended (“Surfacing”) and halts the dive
timer. If the diver does not return below 1.2 m
(4 ft) within the next 3 minutes, Nemo Excel
considers the dive to be finished and records
its data in the Log Book memory. If the diver
does re-descend within 3 minutes, the dive
continues and the dive timer resumes from
where it left off (fig. 33).
Fig. 33
Data displayed in Surface mode:
• duration of the dive;
• maximum depth;
• icons for any mistakes made during the
dive(omitted stop, uncontrolled ascent).
SURFACE MODE  AIR
When the dive is considered finished, Nemo
Excel Excel switches from Dive Mode to Time
Mode, with the desaturation and no-fly times
shown on the display bar as described in the
Time Mode section.
In addition, Nemo Excel displays the icons for
any errors made during the dive (omitted stop,
uncontrolled ascent) (fig. 34).
Fig. 34
For further information, refer to the “Time”
section of this manual.

WARNING
Do not fly or travel to high altitudes while
the no-fly indication remains active.
DIVE  NITROX EAN
Due to the lower percentage of nitrogen in the
breathing mix, oxygen-rich mixtures make
it possible to extend the no-decompression
limits, as compared to the same dive with air.
However, the higher oxygen content in the mix
exposes the diver to oxygen toxicity hazards
which are not generally encountered in
recreational dives with compressed air.
In Nitrox mode, Nemo Excel computes oxygen
toxicity on the basis of the dive time, the depth
and the oxygen percentage setting, providing
indications which enable the diver to remain
within the safe limits for oxygen exposure.
To do a Nitrox dive, it is necessary to select
Nitrox in the Set Dive - Mode menu.
Nemo Excel handles Nitrox dives in a similar
manner to compressed air dives, That means
that you will have the same functions and
procedures for selecting the Dive mode. The
only differences between compressed-air
and Nitrox dives concern the monitoring and
display of Nitrox dive parameters in addition to
the normal air dive parameters (discussed in
the preceding section).
The following section only describes the dive
parameters specific to Nitrox dives, and the
differences in the display layouts.

WARNING
Before the dive, make sure you have
correctly set up all the Nitrox dive
parameters: percentage of oxygen in the
mix and limit for the partial pressure of
oxygen, which together determine the
maximum depth of the dive.

WARNING
It is essential to correctly set the oxygen
percentage in the mix to ensure correct
readouts of:
• no decompression time remaining;
• decompression stop times;
• alarm on exceeding the maximum
permitted PPO
2
.

WARNING
The use of oxygen rich mixes exposes
the diver to different hazards from those
associated with compressed air. The
diver should be aware of these risks and
understand how to avoid them.

WARNING
Nemo Excel should be used for diving with
oxygen rich mixes (Nitrox) only by divers
who have the necessary certification. Lack
of appropriate diver training may result in
possibly serious injury.

WARNING
The user is advised to carefully read the
section on compressed air diving before
reading the section on Nitrox dives.