Measurement without inversion of probing direction
In the above examples, all heights are measured by down hits. All measurements therefore
have a similar probing direction.
Measurement with inversion of probing direction
The above examples show that the measured elements require two hits, one by pushing
upward and one downward. This is called a measurement that requires an inversion of
probing direction as the two measurements have an opposite direction.
The list of measurement functions is defined by two types of keys:
• Action keys (single or double probing)
• Calculation keys