On 08 May, 2017 - Robert Helling wrote:

> Davide,
> 
> > On 8. May 2017, at 17:15, Davide DB <[email protected]> wrote:
> > 
> > I've logged the first few CCR dives with a Shearwater Petrel and a SF2 unit.
> > I discovered that most fields get filled by data coming form the
> > Petrel and some doubt arose on how to correctly log these dives.
> > Basically I find the equipment tab filled with my default cylinder (3
> > liter) and the CC gas set on my Petrel. i.e 3L 18/45 and a column
> > called "use" with the value "OC Gas".
> > I can only change it with "no use". What does it mean?
> > I would expect "CC use". It's my diluent. Of course in my Petrel I
> > have the same mix set as bailout gas but I guess it isn't.
> > Moreover for each dive I have to add another cylinder to record my
> > Oxygen tank setting initial and final pressure.
> > Once I go in the stats tab I find gas calculation only for the 18/45
> > mix, no trace for the oxygen consumption.
> > Why I do not find any data for the Oxygen? Would it be very useful add
> > these tanks by default. I don't know CCR units without a Oxygen tank
> > and actually Oxygen consumption is the most important parameter. Isn't
> > it?
> > If I understand correctly the logic behind I guess I should add my
> > bailout tanks marking them as "no use".
> > 
> > If someone is already using Subsurface proficiently with CCR logs
> > could you give me some hints?
> 
> 
> as was recently discussed on github “OC gas” is a misnomer, the text should 
> be changed to “gas used”.
> 
> To be honest, Subsurface currently does not really do any reasonable gas 
> calculations for CCR dives. As always, it only considers gas used if it is 
> ever switched to and has the implicit assumption that at any moment in time, 
> the diver is only breathing a single gas. Both is of course wrong for CCR 
> dives. Apart from displaying the initial and final pressures of the cylinders 
> anything more advanced is really hard to do (like interpolating pressures for 
> example). For oxygen in CCR dives, I would only make a linear in time 
> interpolation (independent of depth) while predicting diluent use as a 
> function of the depth profile is really hard to do right.
> 

We actually do handle the diluent and o2 consumption simultaneously,
via the MkVI import.

I don't know if you can "activate" that functionality manually.


You can all see it in action when importing the test data
"dives/Poseidon_MkVILog.txt".


//Anton


-- 
Anton Lundin    +46702-161604
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