Salted or fresh water

[Stan]

Le 30/06/2015 23:10, Anton Lundin a écrit :
> On 30 June, 2015 - Stan wrote:
>
>> Hi,
>>
>> Does anybody know how to configure lidivecomputer in order to get depth in
>> fresh water. (Assuming it calibrated for salted water).
>> For the Reefnet Sensus Ultra, I get the raw pressure and then I compute the
>> depth.
>>
>> I guess there is something to change in units.h ?
>>
> Looking at the code, you can adjust the calibration values you're self
> by calling:
>
> reefnet_sensusultra_parser_set_calibration(dc_parser_t *abstract, double atmospheric, double hydrostatic)
>
>
> The defaults are:
> #define ATM         101325.0
> #define GRAVITY     9.80665
>
> parser->atmospheric = ATM;
> parser->hydrostatic = 1025.0 * GRAVITY;
>
>
> And the depth returned is computed by:
>
> #define BAR         100000.0
>
> sample.depth = (depth * BAR / 1000.0 - parser->atmospheric) / parser->hydrostatic;
>
>
> So, in my tired mind, something like:
> reefnet_sensusultra_parser_set_calibration(parser, ATM, 1000.0 * GRAVITY);
>
>
> Should give you your depth for fresh water.
>
>
> //Anton
Assuming the density of the salted water to be 1.025g/l (compares to 
density ==1g/l for fresh water), that should work !
Thanks again Anton.

Stanislas