[PATCH] Visualisation of individual oxygen sensor data for CCR dives

[Anton Lundin]

On 14 April, 2017 - Jef Driesen wrote:

> On 2017-04-13 17:04, Jef Driesen wrote:
> I tried a different approach yesterday. Instead of adding 1024 to
> the calibration value, I simply used the stored value as is, and
> calculated the average ppO2 over all three sensors. Then I plotted
> all those values against the average ppO2 reported by the device.
> And guess what, there is a nice linear relationship between the two!
> Doing a linear regression on the data gives a scaling factor of 2.2.

Interesting find.

> For the example above this gives:
> 
> Sensor 0: 0.642 = 33 mV * 885 / 100000.0 * 2.2
> Sensor 1: 0.630 = 29 mV * 989 / 100000.0 * 2.2
> Sensor 2: 0.674 = 26 mv * 1179 / 100000.0 * 2.2
> 
> As you can see, the average ppO2 (0.648) is now very close to the
> average ppO2 reported by the device (0.65). This seems to be true
> for all samples. The largest difference is now 0.018.
> 
> The next question is of course what's the source of this factor 2.2?

Could it be that the calibration value is stored in some odd format, and
thats where the / 100000.0 * 2.2 part comes from?

> And is correct for all Predators?

How did it line up on the petrels?


//Anton


-- 
Anton Lundin	+46702-161604