comedi_from_physical man page
comedi_from_physical — convert physical units to sample
lsampl_t comedi_from_physical (double data, const comedi_polynomial_t *conversion_polynomial);
Converts data given in physical units into Comedi's integer sample values (lsampl_t, between 0 and maxdata). The conversion_polynomial parameter is obtained from either comedi_get_hardcal_converter() or comedi_get_softcal_converter(). The result will be rounded using the C library's current rounding direction. No range checking of the input data is performed. It is up to you to insure your data is within the limits of the output range you are using.
This function is intended to supplant comedi_from_phys(), and was introduced in order to support software calibrations.
Comedi sample value corresponding to input physical value.