A waveguide runs the length of the cylinder and a magnet in the piston marks position. The electronics launch a pulse down the waveguide and time the torsional return generated where the magnet sits. Nothing touches, nothing wears, and the measurement is absolute.

The sensor knows its position immediately at power-up, with no homing sequence. An incremental sensor must be re-referenced after every power interruption, which on a machine that stops unexpectedly means a homing routine before work resumes - a real operational difference rather than a specification detail.

Not the integrated type, which needs a gun-drilled rod and a magnet in the piston - those are manufacturing features, not additions. External linear transducers, cable-extension sensors and rod-mounted arrangements exist for retrofit, trading some protection and accuracy for the ability to fit what is already installed.

High - magnetostrictive transducers resolve position finely enough for demanding closed-loop motion control, and the figure is usually limited by the control system and the hydraulics rather than by the sensor. Actual positioning accuracy also depends on valve quality and system stiffness.

The whole chain: a position sensor, a controller running the loop, and a proportional or servo valve with its amplifier. Adding a sensor alone gives position indication, not control, and the valve and electronics are usually the larger part of both the cost and the engineering.

Integrated transducers are designed for full system pressure inside the cylinder and are well protected there, which is a major advantage of the approach. External sensors are exposed to the machine environment instead, so ingress protection and mechanical protection become the specification points.

Where only the ends matter, magnetic proximity switches sensing the piston magnet through the barrel are far cheaper and entirely adequate. Continuous position measurement is only needed where intermediate positions must be commanded or known, so the requirement should be established before specifying a transducer.