A 'breakpoint' conversion is a complex set of calculations in which different
equations are applied to input voltages depending on where they lie in relation
to a specified 'breakpoint' voltage. For example, you might apply a linear
conversion to all data of <2 volts, but a polynomial conversion for values
>= 2 volts**.** This window lets you set the breakpoint conversion
conditions:

Each breakpoint conversion operation involves up to three different equations,
each of which can be linear, exponential, 2-order polynomial, or power.
The **initial** conversion is (optionally) applied to all data regardless
of voltage. The other two** 'secondary' **conversions are (optionally)
applied to data above or below breakpoint, respectively. The secondary conversion
can either be **added to or multiplied by** the results of the initial
conversion (this is selected with the '**operator**' buttons) and can
use either raw voltages or the values from the initial conversion (selected
with the '**apply to**' buttons). Note that **the
breakpoint itself is always specified as a raw input voltage**.

The window shows a summary table of the three equations at the bottom.
You enter the coeffients in the three edit fields at top center, and then
click the appropriate button to enter them into the initial or secondary
conversions. The '**get x**' and '**store as x**' buttons let you
save and retrieve up to 6 complete breakpoint conversions **in
memory**. To save them more permanently in a preferences file,
click the '**store values**' button or use the '**store preferences**'
option in the **FILE** menu. If you
save them in a file called "**LabHelper prefs**" and it is
located in the same folder as the **LabHelper** program, it will be loaded
automatically at startup.** **