Dive Terminology - Garmin DESCENT MK1 Owner's Manual

Alert Message
Failed to read depth
sensor. End your dive now.
NDL exceeded. Decom­
pression now required.
PO2 is high. Ascend or
switch to lower O2 gas.
PO2 is low. Descend or
switch to higher O2 gas.
Safe to switch to %1.
Switch now?
Safety Stop Cleared
This pool dive will not be
saved to the dive log.

Dive Terminology

Central nervous system (CNS): A measure of central nervous system oxygen toxicity caused by exposure to
increased partial pressure of oxygen (PO2) while diving.
Closed-circuit rebreather (CCR): A diving mode used for dives performed with a rebreather that recirculates
exhaled gas and removes carbon dioxide.
Maximum operating depth (MOD): The greatest depth at which a breathing gas can be used before the partial
pressure of oxygen (PO2) exceeds the safe limit.
No decompression limit (NDL): A dive that does not require decompression time while ascending to the
surface.
Oxygen toxicity units (OTU): A measure of pulmonary oxygen toxicity caused by exposure to increased partial
pressure of oxygen (PO2) while diving. One OTU is equivalent to breathing 100% oxygen at 1 ATM for 1
minute.
Partial pressure of oxygen (PO2): The pressure of the oxygen in the breathing gas, based on depth and oxygen
percentage.
Surface interval (SI): The amount of time that has elapsed since the completion of the last dive.
Time to surface (TTS): The estimated amount of time it will take to ascend to the surface, including
decompression and safety stops.
Diving
Cause
The device has invalid or missing depth
sensor data after you have started a dive
activity.
You have exceeded your no decompres­
sion limit (NDL) time.
Your PO2 value is above the specified
critical value.
Your PO2 value is below 0.18 bar.
In a multi-gas dive, a gas with a higher
oxygen content is now safe to breathe.
During a dive, "%1" is replaced with the
name of the gas.
You completed the safety stop.
The device is in pool dive mode.
Device Action
Use a backup dive computer or dive
plan and end your dive. Call Garmin
Product Support.
None
Your PO2 value flashes red.
The alert appears every 30 seconds, up
to three times, until you ascend to a
safe level or switch gases.
If you are within the first two minutes
of your dive, your PO2 value flashes
yellow. Otherwise, your PO2 value
flashes red.
The alert appears every 30 seconds, up
to three times, until you descend to a
safe level or switch gases.
You can switch gases now, or wait to
switch gases later in the dive.
None
The device will not save the current
dive to the dive log.
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