OzTek 2017

Anton Lundin glance at acc.umu.se
Sun Jan 22 11:14:47 PST 2017


On 22 January, 2017 - Dirk Hohndel wrote:

> 
> > On Jan 22, 2017, at 2:32 AM, Anton Lundin <glance at acc.umu.se> wrote:
> >> Shearwater we have great relationships with (ok, they still owe me a
> >> response on more details of the new BTLE communication, but hey, they
> >> already sent me a Perdix AI). We used to have a contact at Mares, but he
> >> left. Do they still produce new dive computers?
> > 
> > I would love to get some feedback from them about their calibration
> > values of their O2 sensors. I've reverse-engineered a patch which
> > produces what looks to be the right values, but it would be great if
> > someone with internal knowledge about how its thought could comment on my
> > analysis.
> > 
> > ( The short and curly: Shearwater stores their voted/computed/averaged
> > ppO2, and the mV from the actual sensors in each sample. They also store
> > a "calibration value" in the dive header of unknown unit. If I take that
> > * about 1000 (1024?) the average of the sensors will produce the same
> > ppO2 as they have stored in my sample data. Is that bogus math or is it
> > the right<tm> way? )
> 
> Can you write this up with a bit more context and maybe the pertinent code
> sample and send it to me? I'll be happy to poke them about this.

Here you go.

The real questions are:
What's the unit of the Sensor Calibration values?

What's the unit of the Sensor ADC Offset?

Is the Sensor ADC Offset already factored in into the stored Sensor
millivolts?


//Anton


-- 
Anton Lundin	+46702-161604
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