| 摘要 |
A shiftable valve spool (12) has a plurality of distinct targets (42,44,46) carried thereon. The targets (42,44,46) are preferably axially spaced and located at one end of the valve spool (12). A detector mounted in the valve detects each target (42,44,46) as each target enters a detection field of the detector. The detector generates a distinct output indicative of one target (42,44,46) positioned within the detection field of the detector. A control determines, in response to the output from the detector, the exact valve spool (12) position. <IMAGE> |
