| 摘要 |
<p>The position of a rotating pump element is sensed by a reflective object sensor (406) in association with a view disk (412) coupled to the operative element for rotation in synchrony with the operative element. The view disk has first (S1) and second (S2) surface portions that present themselves in succession to the reflective object sensor during rotation of the operative element. The first surface portion is spaced at or near the optical focus (C) of the reflective object sensor, whereas the second surface portion is not. The reflective object sensor thus generates different outputs, depending upon whether the first surface or second surface portions are in optical alignment with the reflective object sensor.</p> |
