SUUNTO D4 - Manual (Page 31)

NOTE When the backlight is turned OFF, it does not illuminate when an
alarm is activated.
WARNING WHEN THE OXYGEN LIMIT FRACTION INDICATES THAT THE
MAXIMUM LIMIT IS REACHED, YOU MUST IMMEDIATELY
TAKE ACTION TO REDUCE OXYGEN EXPOSURE. Failure to
take action to reduce oxygen exposure after the warning is given
can rapidly increase the risk of oxygen toxicity, injury, or death.
5.7. Error conditions
The dive computer has warning indicators that alert you to react to certain situations
that would significantly increase the risk of DCI. If you do not respond to its warnings,
the dive computer will enter an Error mode, indicating that the risk of DCI has greatly
increased. If you understand the dive computer and operate it sensibly, it is very unlikely
you will ever put the instrument into the Error mode.
Omitted decompression
The Error mode results from omitted decompression, i.e. when you stay above the
ceiling for more than three minutes. During this three-minute period the Er warning is
shown and the audible alarm beeps. After this, the dive computer will enter a permanent
Error mode. The instrument will continue to function normally if you descend below
the ceiling within this three-minute period.
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