SUUNTO D9tx - Manual (Page 57)

In order to minimize the risk of error during a dive, it is highly recommended that the
mixes are set in the proper order. This means that as the mix number rises, so does
oxygen content, and this is the order they are usually used during the dive. Before a
dive, only enable the mixes you actually have available and remember to check the
set values to ensure they are correct.
The ASC time is calculated based on the assumption that you start the ascent profile
immediately and all the PRIMARY gases are changed as soon as their maximum op-
erating depth allows it. That is, using the gases that are set as primary, the most op-
timal ascent schedule for the moment is calculated.
To see the most pessimistic ascent schedule, that is, a schedule for the situation when
gases are not changed at all, you can set the gases as secondary and the time it takes
to finish the decompression using the current breathing gas is shown as the ASC time.
Showing the most pessimistic ascent schedule during a long dive can easily result in
the ascent time no longer fitting the reserved field and the dive computer displays "--
-" (max. 199 min).
NOTE
While setting the gases, notice that the calculated maximum
operating depth is displayed in the upper field. You cannot
change to this gas before you have ascended above this
depth.
In MIXED mode, the default oxygen percentage (O
2
%) setting is 21% (air) and oxygen
partial pressure (PO
2
) setting 1.4 bar.
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