SUUNTO D6I - Manual (Page 51)

In the NITROX setting mode, the equivalent maximum operating depth (MOD), based
on the chosen setting, is displayed. After entering values for Mix1, you can similarly
set an additional mix, Mix2. You can set Mix2 to "Primary", "Secondary" or "Off". Set
the gas as "Primary" if you use the Mix2 for decompression. Set the gas as "Secondary"
if this gas is for back-up/emergency purpose only (for example, dive partner's gas mix
which differs from your own primary gas). "Secondary" gas is not taken into account
in decompression calculations unless you enable it. Mix1 is always set as the "Primary"
gas. The default oxygen percentage (O2%) setting is 21% (air) and oxygen partial
pressure (PO2) setting is 1.4 bar.
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 gases enable as Primary gas are changed as soon as their
maximum operating depth allows it. That is, using the gases that are set as primary,
the most optimal ascent schedule for the moment is calculated.
To view the most pessimistic ascent schedule, that is, a schedule for the situation in
which the gases are not changed at all, you can set the Mix2 gas as Secondary gas,
and the time it takes to finish the decompression using the current breathing gas is
shown as the ASC time. Note however, that 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).
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