Switching Gas Mixture During The Dive; Switching Back To A Gas Mixture With Lower Oxygen Concentration - Uwatec MANTIS User Manual

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 a proper training and certifications to
make multi-gas dives prior of making them by
yourself.
MANTIS 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.
Setting the gas mixture and the depth
for changing the gas mixture
Range of O
The O concentration of gases can only
2
be set in ascending order as show in the
picture above.
O concentration setting shown "--" means
2
that gas is disabled.
MANTIS requires the MODs of gasses to
be at least 3m/10ft apart.
Setting the ppO
to Gas 1 only. Gas 2 and d are always
limited to a maximum value of ppO
1.6bar.
For oxygen concentrations of 80% and
higher, the ppO
cannot be changed.
The MOD for Gas 2 and d are the switch
depths for those gases. This is what
MANTIS uses for its calculations, warnings
and suggested switch points.
When diving with more than one gas
mixture, the Nitrox reset time function
(described in the section on Nitrox reset
time) has the following effect: Gas1 is set to
21% Gas 2 and d are set to OFF.
MANTIS USER MANUAL
O fraction
2
100%
21%
fraction
2
max value to OFF applies
2
2
max is fixed at 1.6 bar and
2
F
NOTE: Start breathing from the tank
with the new gas mixture before
confirming a switch. Always make
sure you are switching to the intended
gas. Failure to do so may result in
serious injury or death.
4.8.1 Switching gas mixture during
the dive
During the ascent phase, when you reach
a depth corresponding to the MOD of Gas
d, MANTIS will suggest that you perform
the switch. An audible sequence goes off,
and the text Gas d starts flashing on the
display together with the value of the MOD.
You have 30 seconds to respond to this
message, otherwise MANTIS will consider
that Gas d will not be used and adapts
the decompression schedule accordingly.
To confirm the gas switch, press the SEL
button. After you confirm the switch, the
text Gas d remains on the screen for five
seconds without flashing.
max of
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