> do you want to say that i must
> asign a decimal value to the
> binary value obtained from the adc?

Not quite that. At first you need
to calibrate your measurement system.
You need to know which digital values
correspond to some *real* measured
values -- and they aren't sometimes
the same as ADC input values due to
their nature. Temperature, for example.
Usually the only math needed later
is interpolation. How many calibration
points to assign to the entire
measurement range, one can estimate by
a few experiments.
Did I answered?

--
Tomas