Shearwater published their approach for po2 > 1.6. Seems pretty conservative and given their position in the market I suspect it would be pretty agreeable to most people to follow their lead.
https://www.shearwater.com/monthly-blog-posts/shearwater-and-the-cns-oxygen-clock/ Dean On Sat, 10 Aug. 2019, 6:30 pm Willem Ferguson, < [email protected]> wrote: > On 2019/08/09 23:23, Robert Helling wrote: > > Willem, > > could you please have a look at the final computation in static double > calculate_cns_dive(const struct dive *dive) > in divelist.c > > It seems to me that the first minus in > > cns += (double)t / ((double)cns_table[j][SINGLE_EXP] - > ((double)po2i - (double)cns_table[j][PO2VAL]) * > (double)cns_table[j][SINGLE_SLOPE] / 10.0) * 100; > > should be plus (at least according to the formula in the comment above. At > least, with this minus, you get negative CNS values for a planned air dive to > 80m of depth. > > Best > > Robert > > > The reason for the negative value is because the dive plan involves pO2 > values above 1.6bar (EAN38 at 35m=pO2 of 1.7bar). The NOAA tables do not > provide values above pO2 = 1.6. > > I am working on a sensible solution because we need a sensible approach > for this use case. > > Kind regards, > > willem > > > > This message and attachments are subject to a disclaimer. > Please refer to > http://upnet.up.ac.za/services/it/documentation/docs/004167.pdf for full > details. > _______________________________________________ > subsurface mailing list > [email protected] > http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface >
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