摘要 |
<p>IMPROVED MAGNETIC SENSING FOR MONITORS AND CONTROLLERS There are disclosed an improved method of and apparatus for use in monitoring or controlling the positional relationship of two relatively movable members. A leading and a trailing magnetic sensing probe are coupled to one of the members. Each probe is fixedly spaced relative to the other probe, and both are arranged so as to cut a magnetic field along a path of varying field strength generated by magnetic means on the other member. Control means are provided for periodically determining the values of the field strength measured by each of the probes and storing a value related to the measured value of a leading one of the probes as viewed in the direction of relative movement. The control means compares the stored value with the present value of the lagging probe so as to define the relative movement in accordance with the incremental separation of the probes and the relationship of the stored and present values.</p> |