Specifications

500AI

Oxygen Accumulation Time Remaining

Oxygen accumulation (exposure) during a dive, or 24 hour period, appears

graphically as the O2 Bar Graph (Fig. 13a). As time remaining before reaching

the oxygen exposure limit decreases, segments are added to the O2 bar graph.

When the amount of time remaining before reaching the oxygen limit becomes

less than the No Decompression Dive Time Remaining, calculations for the

dive will be controlled by oxygen. Oxygen Time Remaining will then appear as

the main numeric time display (Fig. 13b) as signified by the O

icon appearing

to the right of the display.

As oxygen accumulation continues to increase, the O2 bar graph will enter the

yellow Caution Zone. High O2 Mode is explained in detail later in the Han-

dling the Extremes section.

Breathing Gas Time Remaining

The 500AI calculates Breathing Gas Time Remaining using a patented algo-

rithm that is based on a diver's individual breathing gas consumption rate and

current depth. Tank pressure is measured once each second, and an average

rate of consumption is calculated over a 90 second period. This rate of con-

sumption is then used in conjunction with a knowledge of the depth depen-

dence to predict the breathing gas required for the diver to make a safe con-

trolled ascent including any required decompression stops.

Fig. 13 - O2 Accumulation

Time Remaining

140

210

280

350

5000

4000

3000

2000

1000

MAX