Oceanic GEO 4.0, Operating Manual

Page: 20 / 66

20
GEO 4.0 OPERATING MANUAL
© Pelagic, 2019 Doc. No. 12-5670-r01 (2/27/18)
DTR (DIVE TIME REMAINING)
The Geo 4.0 constantly monitors No Decompression status and O2 Accumulation, and will display whichever time is the least amount available as
DTR on the No Decompression Dive Main screen. The Time being displayed will be identified by the NDC min (no decompression time) or O2 min
icons.
NO DECOMPRESSION
No Decompression 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 math-
ematically modeled and compared against a maximum allowable nitrogen level.
Whichever compartment is closest to this maximum level is the controlling compartment for that depth. Its resulting value NDC (no decompression)
will be displayed. It will also be displayed graphically as the TLBG Bar Graph, see Bar Graphs below.
As you ascend, the TLBG Bar Graph segments will recede as control shifts to slower compartments. This is a feature of the decompression model that
is the basis for multilevel diving, one of the most important advantages that Oceanic dive computers offer.
DTR is
No Decompression
O2 MIN (OXYGEN TIME REMAINING)
When set for nitrox operation, O2 SAT (Oxygen Saturation) during a dive is displayed on an ALT screen as a percentage of allowed saturation
identified by the O2 SAT icon. The limit for O2 SAT (100%) is set at 300 OTU (Oxygen Tolerance Units) per dive or 24 hour period. See the chart at
the back of this manual for specific times and allowances. O2 SAT and O2 min values are inversely related; as the O2 SAT value increases the O2
min value decreases.
When the O2 min value becomes less than the No Decompression calculations for the dive, DTR (Dive Time Remaining) will be controlled by O2 SAT
and the O2 min value will be displayed as the DTR on the Dive Main screen, identified by the O2 min icon.
% O
2
Saturation
DTR is O2 MIN
DIVE ALT 3 DIVE MAIN
BAR GRAPHS
The GEO 4.0 features two specific bar graphs.
1. The one on the left represents nitrogen loading. It is referred to as the TLBG (Tissue Loading Bar Graph).
2. The one on the right represents ascent rate. It is referred to as the VARI Bar Graph.
Ascent Rate
Nitrogen Loading