Shearwater CCR tools

[JonG1]

Is anyone else using this app, I have downloaded this weekend and haven't had a good look yet.

It seems to track mv and ppo2 during dive (amongst other data) but how useful is this because exact loop contents would be unknown, unless if course you dil flushed or 02 flushed at 6m.

Or am I missing something?

 

[Noctilux]

Nice tool to check the linearity and behaviour of the cells. You can switch the graph to different types.

 

[JohnnyC]

Are you talking about the android CCR Tools app?

 

[Noctilux]

Yes

 

[taimen]

How do you use it to measure linearity?

 

[Noctilux]

This graph gives me some info for each cell. The green line gives the theoretical curve/line. Blue are measurements and the red line the mV's. The second picture is an example of strange recordings. Does this answer your question?

.

 

[JonG1]

But without knowing the exact composition of the loop ie with an o2 flush or a dil flush can it be that accurate.

And what caused the graph in the 2nd image.

Also what does records IC 95% mean, is it the linearity at 1.0 so 95% linear at initial calibration?

All mine seem to be 95%

 

[taimen]

Well, not completely. Where does this data come from? I assume it is your real life dive data downloaded from Shearwater computer?
I can see a plot with mV against pO2, but where does this pO2 information come from? I could imagine that in a 3-cell rebreather someone could define pO2 as the result of 2 out of 3 cell voting and then plot single cells against that? This type of analysis could reveal a cell becoming current limited before the other two.
But the app has no documentation and the link to the user forum is dead.
So how does it work? How are pO2 and reference defined?

 

[Noctilux]

Good questions!

The data is indeed coming from the shearwater. I asume that the 95% value is the 95% cofidence of the measured data. The graph is only for one cell. The pO2 value is the value displayed on the computer. Which I think is also some kind of an average over time. For that reason the mV are not always directly the same as the displayed pO2.

And I don't know what the problem was in the second graph. It is not visible in my logfile. So probably this is corrected by the computer. So the mV can be seen as an input/measured value and the pO2 is then calculated and not translated 1:1.

 

[rjack321]

Well, not completely. Where does this data come from? I assume it is your real life dive data downloaded from Shearwater computer?
I can see a plot with mV against pO2, but where does this pO2 information come from? I could imagine that in a 3-cell rebreather someone could define pO2 as the result of 2 out of 3 cell voting and then plot single cells against that? This type of analysis could reveal a cell becoming current limited before the other two.
But the app has no documentation and the link to the user forum is dead.
So how does it work? How are pO2 and reference defined?

reference would in theory be 1:1 for the theoretical mv : pO2 slope
The rest is dubious. I don't know how the software knows the true loop contents.