22
Variable Ascent Rate Indicator
™
- (VARI)
The VARI occupies the bottom portion of the PRODIGY display (Fig.
18b). The purpose of the VARI is to assist the diver in preventing too rapid
an ascent by providing a visual indication of ascent speed. The bar graph is
made up of 5 triangular segments and is analogous to an ascent rate speed-
ometer. There are various speed “zones” that are color–coded green, yellow,
and red. The actual speeds that the VARI segments represent are listed on
page 58. Flashing VARI segments alert the diver of an ascent rate that has
exceeded 60 feet (18 meters) per minute (red VARI zone). The Variable
Ascent Rate Indicator currently holds a U.S. Patent.
DIVE TIME REMAINING DISPLAY
One of the most important pieces of information on the PRODIGY is the
no-decompression dive time remaining display (Fig. 19a). The PRODIGY
constantly monitors theoretical loading of twelve different tissue compart-
ments and calculates no-decompression time based on the amount of nitrogen
absorbed by these hypothetical compartments. The rates at which each of
these compartments absorb and release nitrogen is mathematically modeled
and compared against a maximum allowable nitrogen level. Whichever one of
the twelve is closest to this maximum level, known as the no-decompression
limit, will be considered the controlling compartment for that depth. Its
resulting theoretical value will be displayed as the No-Decompression Time
Remaining display and the TLBG.
Fig. 19 – No-decompression
Dive Time Remaining
®
FT
a.
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