Can you modify the device under measurement? if you put into the tank two
close conductive foils, and the liquid is dielectric, yo can measure
capacitance between the foils, and the measure will be linear because
capacitance is linear to S in a two foil parallel condenser. If this is not
possible, i think that te best way is to measure any electrical magnitude
(with a arm buoy coupled to a potentiometer, by example), at certain points
while the level of liquid raises, and keep the measured values in an array
and then compare. The resolution of the resultant comparation will depend on
the resolution of the previously taken measures. If this is not good, you
always could apply the basic diferential approach. Integer from zero to h of
a rectangle of know length, variable side, diferential of side. the
diferential of side can be translated then from the formula of a secant of a
circle (it seems too difficult to program easily, but if there is no other
way...)

keep on PICing.


>Hi !
>I have a cylindrical tank lying on its side (like a fallen beer can -
umm...
>someone WILL make a joke about this!). The diameter and lenght is known,
but
>I should measure the volume of the liquid inside by metering the level.
Now,
>because the sides are rounded, the level of the liquid doesn't increase
>linearly as the liquid is added evenly.
>Could someone help me to calculate this?
>
>juha.tuomi@liperi.inet.fi
>