12
O
2
ATR
5
10
20
40
50
60
0
O
2
30
As your oxygen exposure (accumulation) increases during the
dive, segments will add to the Bar Graph, and as loading de-
creases, it will begin to recede, indicating that additional expo-
sure is allowed for that dive and 24 hour period.
Variable Ascent Rate Indicator (VARI)
The Variable Ascent Rate Indicator (Fig. 3a) provides a visual
representation of ascent speed (i.e., an ascent speedometer).
Green is a 'normal' rate, yellow a 'caution' rate, and red is 'Too
Fast'. The segments of the VARI represent two sets of speeds
which change at a reference depth of 60 feet (18 meters). Refer
to the chart for segment values.
WARNING: At depths greater than 60 feet (18 meters),
ascent rates should not exceed 60 fpm (18 mpm). At
depths of 60 feet (18 meters) and shallower, ascent
rates should not exceed 30 fpm (9 mpm).
Air Time Remaining Bar Graph (ATRBG)
The Air Time Remaining Bar Graph (Fig. 3b) provides a graphic
representation of the time that you can remain at your present
depth and then, following a safe ascent, surface with a predeter-
mined reserve of Air. This calculation and display is based on
your Air Consumption Rate that is continuously monitored by the
VT Pro, and it takes into account the air required for a safe
ascent including any required decompression stops.
Fig. 3 - VARI & ATRBG
a
60 feet (18 m) & Shallower
Segments
Ascent Rate =
Displayed
FPM
MPM
0
0-10
0 - 3
1
11-15 3.5-4.5
2
16-20 5-6
3
21-25 6.5-7.5
4
26-30 8-9
5
>30
>9
Deeper than 60 feet (18 m)
Segments
Ascent Rate =
Displayed
FPM
MPM
0
0-20
0 - 6
1
21-30 6.5-9
2
31-40 9.5-12
3
41-50 12.5-15
4
51-60 15.5-18
5
>60
>18
VARI Values
b
