47
English
M2 USER MANUAL
and holding the SEL/ESC button. The M2 will
display the text Gas 1 and its MOD, flashing. At
this point press +/UP to select Gas 2 or press
the SEL button to confirm the switch. The M2
will display the text Gas 1 for five seconds
without flashing and adapt the decompression
schedule accordingly.
4.9.3
Gas switch not carried out at
the planned depth
If you fail to confirm the gas change
within the 30 seconds of when the M2
suggests it, the gas is excluded from
the decompression calculation and the
decompression schedule is adapted
accordingly, basically reflecting the fact that
you will finish the dive without using the
excluded gas.
F
NOTE:
If, after the M2 has changed
the decompression schedule to reflect
the missed gas switch, you descend
again below the MOD for Gas d, the
M2 will reintroduce Gas d into the
calculations and the decompression
schedule will change accordingly
.
4.9.4
Delayed gas switch
You can catch up on a planned gas mixture
switch at any time by selecting the gas
manually. Press and hold the SEL/ESC
button to start the gas switch procedure.
The M2 will show the text Gas 2 or Gas d
and its MOD flashing on the display. This
helps you verify that you are performing
a switch to a safe gas. At this point you
would press the SEL/ESC button to
confirm the switch. The M2 will display the
text Gas d without flashing and adapt the
decompression schedule accordingly.
4.9.5
Submerging below the MOD
after a gas switch
If after having switched to Gas d or Gas 2 you
inadvertently drop again below the MOD for
that mixture, the MOD alarm will immediately
be activated. In this case, you would either
switch back to Gas 1 or ascend above the
MOD for Gas d or Gas 2.
4.9.6
Diving with CCR mode
The CCR (Closed Circuit Rebreather) system
is probably older than the Open Circuit
SCUBA system because the basic operating
principle with manual control didn’t require a
highly reliable regulator system.
The CCR system also uses the gas more
efficiently than an open loop system,
because the oxygen is added to the
breathing loop only as needed. Respectively,
the carbon dioxide generated by the body
is bound to calc at the scrubber. As a side
effect the CCR system is nearly bubble-free,
which can be beneficial when engaged in
photography or observing fishes underwater.
In the CCR system the breathing gas ppO
2
(partial pressure of the oxygen) is kept
constant. The CCR system itself takes care
of this. Compared to an open loop system
the constant ppO
2
converts to a variable
nitrox mix at different depths.
For example, a ppO
2
setting of 1.0bar is
comparable to an open loop 50% nitrox mix
at a depth of 10 meters in salt water.
WARNING
All rebreathers require unit specific education
before using them. Get the proper certifications
and follow manufacturer recommendations and
procedures when diving with a rebreather unit.
Deviations may lead to severe injury or death.
Summary of Contents for M2
Page 1: ... M2 User Manual ...
