For long distances and when it is not possible to work with a rigid axis , we can apply the technology of measurement by cable.
The transmitter transforms a lineal move of the cable in a rotation of the axis proportional to the distance (number of rounds and angle).
This mechanical processing of a linear displacement to an angular one, is measured by any angular measurement system described in the angular measurement section.
In general, the more economic devices incorporate an angular potenciómetro (with direct output or amplified) or an encoder.