SUUNTO D4i - Manual (Page 70)

6.1.3. Tank pressure data
When using the optional wireless pressure transmitter, the pressure of your scuba
cylinder in bars (or psi) is shown digitally in the lower left corner of the alternative dis-
play. Whenever you start a dive, the remaining air time calculation begins. After 30–60
seconds (sometimes more, depending on your air consumption), the first estimation
of remaining air time is shown in the left center window of the display. The calculation
is always based on the actual pressure drop in your cylinder and automatically adapts
to your cylinder size and current air consumption.
CURRENT TANK PRESSURE
IS 165 BAR AND THE REMAINING
AIR TIME IS 52 MINUTES.
The change in your air consumption is based on constant one second interval pressure
measurements over 30–60 second periods. An increase in air consumption influences
the remaining air time rapidly, while a drop in air consumption increases the air time
slowly. In this way, an over optimistic air time estimation, caused by a temporary drop
in air consumption, is avoided.
The remaining air time calculation includes a 35 bar/500 psi safety reserve. This means
that when the instrument shows the air time to be zero, there is still about 35 bar/500
psi of pressure left in your cylinder, depending on your air consumption rate. With a
high consumption rate, the limit will be closer to 50 bar/700 psi and with a low rate
closer to 35 bar/500 psi.
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