Have been doing research on CNS Oxygen Exposure over the last two days. I understand that most computers do CNS Oxygen Exposure calculations *live* for you while diving, but I wanted to understand the underlying math and algorithms that they use.
Of particular interest to me was the difference between the PADI Oxygen exposure table and the more detailed multi-level calculations that my computer appears to be doing. The PADI table just lists a highest PP02 and the max dive time allowed. This would force one to use a square profile for the dive. The computer appears to do a multi-level dive calculation giving credit for shallower depths.
The best reference that I have found is the NOAA Divers Manual, Chapter 3 which gives % saturation calculations for various PP02s in 5 minute intervals. This would allow one to calculate Oxygen saturation in multi-level and repetitive dives manually
As I researched the Shearwater algorithms it appears they have extrapolated the data in the NOAA 5 minute interval tables to do live calculations.
Two questions:
1. Do other computer manufacturers do the same thing?
2. Is there a published table somewhere that shows the data with a data interval of less than 5 minutes?
Of particular interest to me was the difference between the PADI Oxygen exposure table and the more detailed multi-level calculations that my computer appears to be doing. The PADI table just lists a highest PP02 and the max dive time allowed. This would force one to use a square profile for the dive. The computer appears to do a multi-level dive calculation giving credit for shallower depths.
The best reference that I have found is the NOAA Divers Manual, Chapter 3 which gives % saturation calculations for various PP02s in 5 minute intervals. This would allow one to calculate Oxygen saturation in multi-level and repetitive dives manually
As I researched the Shearwater algorithms it appears they have extrapolated the data in the NOAA 5 minute interval tables to do live calculations.
Two questions:
1. Do other computer manufacturers do the same thing?
2. Is there a published table somewhere that shows the data with a data interval of less than 5 minutes?