Technical information

3. Meridian as a dive computer
3. Meridian as a dive computer
39
English
SCUBAPRO MERIDIAN
something  did  not  work  as  planned. 
WARNING
• Diving with two 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 two 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 a proper training and certifications to
make multi-gas dives prior of making them.
Meridian enables you to use up to two gas 
mixtures  during  the  dive  (air  and  Nitrox 
only). The two mixtures are labeled  1  and 
d, and must be  in  ascending  order of the 
oxygen fraction. 
1 d
d
Time
Bottom mix
Diving with 2 gas mixtures
Deco mix
Depth
Switching gas mixture during the dive
During the ascent phase, when you reach a 
depth corresponding to the MOD of Gas d, 
Meridian 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 Meridian will consider 
that Gas d will not be used and adapts the 
decompression  schedule  accordingly.  To 
confirm  the  gas  switch,  press SEL/ESC
button.
F
NOTE: Start breathing from the tank
with the new gas mixture before
confirming a switch.
WARNING
Always make sure you are switching to the
intended gas. Failure to do so may result in
serious injury or death.
After  you  confirm  the  switch,  the  text 
Gas d remains  on  the  screen  for  five 
seconds without flashing.
Switching back to a gas mixture with
lower oxygen concentration
There may be situations in which you have 
to switch back to Gas 1from Gas d. This 
can  happen  for  instance  if  you  want  to 
descend again below the MOD for Gas d, 
or if  for  instance  you  have  run out of Gas 
d during the decompression. At this point 
you can manually initiate the gas switch by 
pressing and holding SEL/ESC  button. 
Meridian  will  display  the  text  Gas 1 and 
its  MOD,  flashing.  At  this  point  press
SEL/ESC button to  confirm  the  switch. 
Meridian will display the text Gas 1for five 
seconds  without  flashing  and  adapt  the 
decompression schedule accordingly. 
Gas switch not carried out at the
planned depth
If you  fail  to confirm the change to Gas  d
within  the  30  seconds  of  when  Meridian 
suggested  it,  Gas  d is  excluded  from 
the  decompression  calculation  and  the 
decompression  schedule  is  adapted