Suunto D6I manual

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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