Missing pO2 samples from CCR download [was: 4.7.8: a couple of questions]

Jef Driesen jef at libdivecomputer.org
Fri May 25 09:24:03 PDT 2018

On 25-05-18 16:35, Willem Ferguson wrote:
> On 25/05/2018 15:55, Jef Driesen wrote:
>> The main disadvantage is that you'll no longer know which type of ppO2
>> (sensor or voted/average) you are getting. Especially if you only have
>> one sensor.
> I would agree, but at least one gets the calculated pO2 as perceived by
> the machine at the time, even though there is no idea about sensor
> problems during the dive. It is so much better than having no pO2 data
> to evaluate after a dive. This pO2  would still correspond to the data
> in the pO2 graph of the Shearwater Desktop software.
> I do not quite get the argument about one sensor? For one sensor there
> is no averaging or voting?? I'm not seeing something, so please spell it
> out?

The average ppO2 is always a single value. But there is often more than one 
sensor. So you could assume that if you get more than one ppO2 value that they 
are values from a sensor. But in the case of a single sensor, that doesn't work, 
and you won't be able to tell which value you got.

I'm not sure if the average ppO2 is always equal to the sensor ppO2 for the 
single sensor case. Maybe the dive computer does averaging over several 
measurements to ignore outliers? (Is simply don't know.)


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