Operating Instructions
Page 16
Doc. 15301-RevB (2023-11-24)
3.6. Info Screen Descriptions
Last Dive Info
Maximum depth and dive time from the last dive� Only
available at the surface�
Maximum Depth
The maximum depth of the current
dive� When not diving, displays the
maximum depth of the last dive
Average Depth
Displays the average depth of the
current dive, updated once per
second� When not diving, displays
the average depth of the last dive�
Maximum Operating Depth
MOD is the maximum allowable
depth of the current breathing gas
in the currently selected depth units
as determined by PPO2 limits�
Displays in Flashing Red when exceeded�
Read more about PPO2 Limits on page 52�
m
m
MODCNS
%
11
m
min
PPO2
.2157
SURFACE
m
CNS Toxicity Percentage
Central Nervous System oxygen
toxicity loading percentage� Turns
Red when greater than 100%�
The CNS percentage is calculated
continuously, even when on the
surface and turned off� When deco
tissues are reset, the CNS will also
be reset�
The CNS value (short for Central Nervous System
Oxygen Toxicity) is a measure of how long you have
been exposed to elevated partial pressures of oxygen
(PPO2) as a percentage of a maximum allowable
exposure� As PPO2 goes up, the maximum allowable
exposure time goes down� The table we use is from
the NOAA Diving Manual (Fourth Edition)� The
computer linearly interpolates between these points
and extrapolates beyond them when necessary�
Above a PPO2 of 1�65 ATA, the CNS rate increases at a
fixed rate of 1% every 4 seconds�
During a dive the CNS never decreases� When back at
the surface, a half-life of elimination of 90 minutes is
used�
So for example, if at the end of the dive the CNS was
80%, then 90 minutes later it will be 40%� In 90 more
minutes it will be 20%, etc� Typically after about 6
half-life times (9 hours), everything is back close to
equilibrium (0%)�
%
11
m
min
PPO2
1.0257
TTS
OC
SURFACE
mh
3412
NDL
%
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