Embodiments of the present invention provide a pendulum valve with a full range of normal position control. The probe includes a probe body having a proximal and distal end, a probe tip located at the distal end of the probe body, the probe being configured such that, when the probe tip is applied to the surface, the probe tip is moved to rotate about its axis, whereby the shaft tip can rotatably remove oxidation andor contamination debris from between the shaft tip and the surface. The lengths of the offset PES offset segments are systematically varied in a repeating pattern to provide a unique servo signal pattern for each track in a local group of adjacent tracks.