SUUNTO COBRA User Guide - Manual (Page 70)

6.2.1. Before diving in the NITROX mode
If set to the NITROX mode, the correct oxygen percentage of the gas in your cylinder
must always be entered into the computer to ensure correct nitrogen and oxygen
calculations. The dive computer adjusts its mathematical nitrogen and oxygen calcu-
lation models accordingly. The dive computer will not accept fractional percentage
values of oxygen concentration. Do not round up fractional percentages. For example,
31.8% oxygen should be entered as 31%. If you want to adjust the computer to provide
more conservative calculations, use the personal adjustment feature to affect decom-
pression calculations, or reduce the PO
2
setting to affect oxygen exposure according
to the entered O
2
% and PO
2
values. Calculations based on nitrox use result in longer
no-decompression times and shallower maximum depths than diving with air.
When the dive computer is set in NITROX mode, the Dive Planning mode calculates
using the O
2
% and PO
2
values that are currently in the computer.
Default nitrox settings
In the NITROX mode, the default setting is standard air (21% O
2
). It remains in this
setting until the O
2
% is adjusted to any other percentage of oxygen (22%–50%). The
default setting for maximum oxygen partial pressure is 1.4 bar, however you are able
to set it in the range of 1.2–1.6 bar.
If unused, the computer will retain the manually entered value for the selected oxygen
percentage for about two hours, after which it will revert to the default setting of 21%
O
2
.
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