Cylinder pressure interpolation and end pressure display for CCR

[Robert C. Helling]

On 09 Nov 2014, at 12:49, Willem Ferguson <willemferguson at zoology.up.ac.za> wrote:

Hi,

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> As far as the present implementation is concerned, I suspect it would be fairly easy (not simple) to to changes. We just need to agree on the principle of interpolation for the diluent.

ok, so here is my attempt at this: The first patch adds a strategy parameter to the interpolation. For all OC gases we use SAC-based while for both CCR gases we now use TIME-based (as long as we have continuous señor readings for diluent as in your example that should be fine).

While reading your code I realised that some of our confusion resulted from the fact that you wanted to treat the O2 cylinder as an extension of the current cylinder in the OC case and make the diluent the additional cylinder. What I had in mind (and I think this is the better way since it makes it more straight forward to determine the breathing gas) is to treat the diluent as the normal case and O2 as special. So the second patch is a code refactor which implements this switch. For me, this was a bit like open heart surgery and I am not convinced I did not miss anything. So this needs some testing and looking at code.

This also affects the xml format for those dives: The O2 pressure gets a special keyword while the diluent is now just “pressure”. I changed the sample file with search&replace but you should better regenerate it (I don’t know how you did that).

Best
Robert

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Robert C. Helling     Elite Master Course Theoretical and Mathematical Physics  
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