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English
M2 USER MANUAL
System effects and less dangerous long-
term Pulmonary Toxicity effects.
The M2 treats high ppO
2
and long exposure
effects in the following ways:
1. Against sudden effects
: the M2 has
an MOD alarm set for a user-defined
ppO
2
max. As you enter the oxygen
concentration for the dive, the M2 shows
you the corresponding MOD for the defined
ppO
2
max. The default value of ppO
2
max
from the factory is 1.4bar. This can be
adjusted to your preference between 1.0
and 1.6bar. It can also be turned off. Please
refer to the chapter on Gas settings for
more information on how to change this
setting.
2. Against long exposure effects
: the
M2 “tracks” the exposure by means of the
CNS O
2
clock. At levels of 100% and higher
there is risk of long exposure effects, and
consequently the M2 will activate an alarm
when this level of CNS O
2
is reached. The
M2 can also warn you when the CNS O
2
level reaches 75% (see section CNS O
2
= 75%). Note that the CNS O
2
clock is
independent of the value of ppO
2
max set
by the user.
The CNS O
2
clock increases when the
oxygen partial pressure is higher than
0.5bar, and decreases when the oxygen
partial pressure is lower than 0.5bar.
Hence, while on the surface breathing air
you will always be decreasing the CNS O
2
clock. During the dive, the depth at which
0.5bar is reached for various mixes is as
follows:
• Air: 13m/43ft
• 32%: 6m/20ft
• 36%: 4m/13ft
F
NOTE: For oxygen concentrations of
80% and higher, the ppO
2
max is fixed
at 1.6bar and cannot be changed.
F
NOTE: Repetitive very long exposures
(technical and rebreather diving) with
high ppO
2
may cause long-term
Pulmonary Toxicity effects that can
be tracked with OTUs. SCUBAPRO
recommends the model Galileo TMx
for completing such dives.
4.9 Diving with two or more
gas mixtures
The M2 is equipped with the ZH-L8
ADT MB PMG algorithm. PMG stands
for Predictive Multi Gas, meaning that
when you program more than one gas
mixture, the M2 will predict the switch
to the higher oxygen concentration gas
at the depth that you specified and alert
you at all times with a comprehensive
decompression schedule of all the gas
mixtures that you programmed. In other
words, you get full credit at any point
during the dive for all the extra gas
mixtures that you are carrying with you.
At the same time the M2 can also show
you what the decompression schedule
would be if you were to finish the dive
using only the gas mixture that you are
currently breathing from, so that you can
be prepared in the event that something
doesn’t work as planned.
WARNING
Diving with multiple gas mixtures represents a
much higher risk than diving with a single gas
mixture, and mistakes by the diver may lead to
serious injury or death.
During dives with multiple gas mixtures,
always make sure you are breathing from the
tank that you intend to breathe from. Breathing
from a high oxygen concentration mix at the
wrong depth can kill you.
Mark all your regulators and tanks so that you
cannot confuse them under any circumstance.
Before each dive and after changing a tank,
ensure that each gas mixture is set to the
correct value for the corresponding tank.
Get the proper training and certifications to
make multi gas dives prior to making them by
yourself.
The M2 enables you to use up to three
gas mixtures during the dive (air and nitrox
only). The three mixtures are labeled 1, 2
and d, and must be in ascending order of
the oxygen fraction.
Summary of Contents for M2
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