Step 4 defines the calculation of the output signals.
There are two linear functions to transform the unity coordinates
of X and Y to physical quantities using imports C to F. With a differential
amplifier and an integration the closed-loop is implemented to hold a constant
distance. This is controlled by imports G (locked tunnel current)
and H (reaction factor) and exports the result in point 3. Please note
that 21st Century Project calculates with ranges of quantities, which makes
it easy to control measurement errors and missing values.
