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OCi OPERATING MANUAL
© 2002 Design, 2013 Doc. No. 12-5335-r01 (6/27/13)
DIVE TIME REMAINING (DTR)
The OCi constantly monitors No Deco status (nitrogen loading) and O2 accumulation, and will use whichever time is the least
available to calculate DTR.
Either NDC (No Deco Time Remaining), or OTR (O2 Time Remaining), is displayed as DTR (Dive Time Remaining) on the Dive
Main screen (Fig. 65A/B). The graphic NDC or OTR will signify which time is being displayed.
NO DECO DIVE TIME REMAINING (NDC)
NDC is the maximum amount of time that you can stay at your present depth before entering decompression. It is calculated
based on the amount of nitrogen absorbed by hypothetical tissue compartments.
• The rates each of these compartments absorb and release nitrogen is mathematically modeled and compared against a
maximum allowable nitrogen level.
• Whichever one is closest to this maximum level is the controlling compartment for that depth. Its resulting value will be
displayed numerically as NDC time remaining and graphically as the TLBG (Tissue Loading Bar Graph).
• As you ascend, TLBG segments will recede as control shifts to slower compartments. This feature of the decompression
model is the basis for multilevel diving, one of the most important advantages that Oceanic dive computers offer.
O2 DIVE TIME REMAINING (OTR)
When set for Nitrox operation, O2 during a dive is displayed on an ALT screen as a % of total exposure allowed (Fig. 66).
The limit for oxygen exposure (100%) is 300 OTU (oxygen tolerance units) per dive or 24 hour period.
As time before reaching the limit decreases, % O2 increases and oxygen time remaining (OTR) decreases.
When OTR becomes less than the NDC, calculations for the dive will be controlled by O2 and OTR will be displayed on the
Main. NDC will then be displayed on an ALT screen that can be accessed.
AIR TIME REMAINING (ATR)
The OCi
calculates ATR using a patented algorithm that is based on the diver's air consumption rate and current depth.
ATR is the time you can remain at your present depth and still safely surface with the tank pressure reserve that you selected dur-
ing setup (the End Pressure alarm setting).
Tank pressure is measured once each second and an average rate of consumption is calculated over a 90 second period, and
used in conjunction with the depth to predict the amount of air required to make a safe controlled ascent, including the No Deco
Deep and Safety Stops and any required Deco Stops.
Air consumption and depth are continuously monitored and ATR reflects any change in circumstances, such as beginning to
breath more rapidly when swimming against a current which the OCi will recognize as a change and adjust ATR accordingly.
ATR is displayed numerically (from 0 to 99* min) on the Dive Main screen (Fig. 67).
*ATR remains at 99 min when => 99 minutes.
ATR Alarm
When ATR (Air Time Remaining) decreases to 5 minutes, the audible will sound and the ATR digits will flash (Fig. 68). If it de-
creases to 0, the audible will sound again. The digits will continue to flash until ATR becomes greater than 5 minutes.
Action (upon activation of the alarm) >> You should initiate a controlled ascent while monitoring tank pressure. However, there
is no reason to panic, the OCi has allowed for the air necessary for a safe ascent including the No Deco Deep and Safety
Stops, if set on, and any Deco Stops required.
RESET DURING A DIVE (ERROR)
If for any reason, the OCi shuts Off then turns On again during any dive, the graphics UP and ERROR will be displayed with the
Up Arrow icons and current Depth with FT (or M) icon (Fig. 69).
If this occurs, it is highly recommended that you terminate the dive and begin a safe ascent to the surface.
Upon surfacing, ERROR will be displayed for 5 seconds (Fig. 70) and operation will revert to Watch Mode.
Any time thereafter, when access to Dive Computer Operating Mode is attempted from Watch Mode, only the graphic ERROR
will be displayed and operation will revert to Watch Mode. No Dive Computer modes/screens will be accessible.
If this occurs, the OCi must be returned to the factory for evaluation/service prior to any further use for diving activities.
Fig. 65A -NO DECO MAIN
(NDC is DTR)
Fig. 66 - NO DECO ALT 3
(% of O2 Saturation)
Fig. 69 -ERROR
(during dive)
Fig. 70 -ERROR
(after surfacing)
Fig. 65B -NO DECO MAIN
(OTR is DTR)
Fig. 67 - NO DECO MAIN
(38 min ATR remaining)
Fig. 68 - NO DECO MAIN
(during ATR Alarm)