Instruction manual

Page 150
Universal Linear (P600=11)
This volume calculation creates a linear approximation of the level/volume
relationship, and works best if the vessel has sharp angles between each
section.
Level
Volume
You should enter a level/volume breakpoint for each place where the vessel
changes direction, and numerous where the section is slightly curved
(mostly linear, but has got a small arc). You can enter any number of pairs
between 2 and 32.
Universal Curved (P600=12)
This volume calculation creates a curved approximation of the level/volume
relationship, and works best if the vessel is non-linear, and there are no
sharp angles.
Level
Volume
You should enter 2 level/volume breakpoints at the minimum and maximum
levels, and several for each place where the vessel has got an arc. You can
enter any number of pairs between 2 and 32.