Display Below Ceiling Zone
The CEILING/ASC TIME symbol and upwards
pointing arrow indicate that you are below the ceiling
zone (Fig. 3.13). You should start your ascent imme-
diately.
Display At Ceiling Zone
When you reach the ceiling zone, the display will
show you two arrows pointing toward each other
(the “hour glass” icon, Fig. 3.14). The two arrows
pointing toward each other will be shown between
the minimum ceiling and 1.8 m [6 ft] below the min-
imum ceiling. All decompression stops must be per-
formed at or below the ceiling depth range.
The depth of the ceiling will depend on your dive
profile. It will be fairly shallow when you enter the
decompression mode, but if you remain at depth, it
will move downward and the ascent time will
increase.
The ceiling depth will be shown on the left side of the center window.
When the sea surface is rough, it may be difficult to maintain a constant depth
near the surface. In this case it will be more manageable to maintain an addi-
tional distance below to the ceiling, to make sure that the waves do not lift you
above the ceiling. TUSA recommends that decompression takes place deeper
than 4 m [13 ft], even if the indicated ceiling is shallower.
Display Above Ceiling
If you ascend above the ceiling, a downward pointing arrow will appear (Fig
3.15). In addition a blinking error warning Er reminds you that you have only
three minutes to correct the situation. You must immediately descend to or
below the ceiling.
If you continue to violate the decompression requirements, the
IQ-400
goes
into a permanent ERROR MODE. In this mode (Fig. 3.16) you must not dive
again for at least two days. See also Section 3.6, Error Conditions.
22
Figure 3.15
Decompression Dive,
Above Ceiling
Note the downward
pointing arrow and the
blinking Er warning, You
should immediately
(within 3 minutes)
descend to or below the
ceiling.
DIVE TIME
CEILING
ASC
A 1
A
m
S
C
S
P
E
E
D
HIS
LOG
ALT
SET
PLAN
¡C
NOTE
It will take more time and more air to decompress below the
ceiling than at the ceiling.
!
!
