7. PDIS (Profile Dependent Intermediate Stop)
7.3
Special considerations
when diving with more
than one gas mixture
(Aladin 2G)
Switching to a higher oxygen concentration
mix during the dive influences the PDI stop.
This needs to be accounted for, in line with
the predictive nature of multigas handling in
ZH-L8 ADT MB PMG.
When diving with more than one gas
mixture, Aladin 2G displays the PDIS depth
according to the following rules:
• if the PDI stop calculated for the bottom
mix (gas 1) is deeper than the switch
depth, than this calculated value is
displayed;
• if the PDI stop calculated for gas 1
is shallower than the switch depth to
gas d, then the displayed PDI stop is a
function of gas d.
In case of a missed gas switch, Aladin 2G
reverts to the PDI stop for the actively
breathed mix.
7.4
Diving with PDIS
)
NOTE:
To use the PDIS feature, you must set
PDIS to ON in the PDIS menu under
Set 1. The default setting is OFF.
When the calculated PDI stop is deeper
than 8m/25ft, Aladin 2G shows it on
the display and continues to do so until
you reach the displayed depth during
an ascent. The displayed value changes
during the dive as Aladin 2G tracks the
uptake of nitrogen in the 8 compartments
46
and updates the PDIS depth accordingly to
reflect the optimum at all times.
The PDIS depth is shown in the lower left
corner, with the label PDIS. During a no-
stop dive, as soon as you reach that depth
during an ascent, a 2-minute countdown
will appear in place of the no-stop value
with label STOP. In addition, the PDIS
label will blink. You can have one of three
situations:
• you have spent 2 minutes within 3m/10ft
above the indicated depth. The
countdown timer disappears and the
PDIS value is replaced by the label
YES as an indication that you have
performed the PDI stop;
• you have descended by more
than 0.5m/2ft below the PDIS. The
countdown timer disappears and will
reappear again, starting at 2 minutes,
the next time you ascend to the PDIS
depth;
• you have ascended by more than
3m/10ft above the PDIS. The PDIS
value and countdown timer are replaced
by the label NO to indicate the fact that
you have not performed the PDI stop.
If Aladin 2G is displaying a decompression
obligation when you reach the PDIS depth
during an ascent, all rules apply the same
way, but the 2-minute countdown runs in
the background and is not displayed on
the screen. The PDIS label however will still
be blinking to show you that you are in the
PDIS range.
SCUBAPRO ALADIN 2G