SUUNTO EON STEEL - Manual (Page 24)

In such a condition, you should descend back below the ceiling level
to continue the decompression. If you fail to do so within three (3)
minutes, Suunto EON Steel locks the algorithm calculation and
displays ERROR instead, as shown below. Note that the ceiling value
is no longer present.
In this state, you significantly increase your risk of decompression
sickness (DCS). Decompression information is not available for the
next 48 hours after surfacing.
It is possible to dive with the device when the algorithm is locked,
but instead of the decompression information, ERROR is shown.
Going to dive mode when algorithm is locked resets the algorithm
lock time back to 48 hours when you surface.
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