A sensor arrangement is arranged to detect at least one position of a displaceable component in a fluid device, which fluid device comprises a wall enclosing a cavity, in which cavity the component is displaced by pressurized fluid selectively applied to the component. The sensor arrangement includes a magnetic sensor mounted outside the wall and a first sensor element that is connected to the magnetic sensor and extends through the wall and a predetermined distance into the cavity. The magnetic sensor is arranged to detect the position of at least one predetermined second sensor element located on the displaceable component by sensing a change in magnetic flux induced in the first sensor element by the second sensor element.