Operation Manual

DIVE TIME REMAINING (DTR)

One of the most important pieces of information on AERIS dive computers is the 'Dive Time Re-

maining (DTR) display'. The dive computer constantly monitors no decompression status.

No Deco Dive Time Remaining (DTR)

No Deco Dive Time Remaining (DTR) is the maximum amount of time that you can stay at your

present depth before entering a decompression situation. It is calculated based on the amount of

nitrogen absorbed by hypothetical tissue compartments. The rates each of these compartments ab-

sorb and release nitrogen is mathematically modeled and compared against a maximum allowable

nitrogen level. Whichever one is closest to this maximum level is the controlling compartment for

that depth. Its resulting value will be displayed numerically (Fig. 9a) along with the No Decom-

pression Dive icon and graphically as the Nitrogen Bar Graph (Fig. 9b).

As you ascend from depth following a dive that has approached the

no decompression limit, the Nitrogen Bar Graph will recede as

control shifts to slower compartments. This is a feature of the de-

compression model that is the basis for multilevel diving, one of

the most important advantages that AERIS dive computers offer.

The no decompression algorithm is based upon Haldanes theory

using maximum allowable nitrogen levels developed by Merrill

Spencer. Repetitive diving control is based upon experiments de-

signed and conducted by Dr. Ray Rogers and Dr. Michael Powell

in 1987. Diving Science and Technology

(DSAT), a corporate af-

filiate of PADI

, commissioned these experiments.

Fig. 9 - No Deco DTR