| 摘要 |
A non-contacting gauge for measuring thickness deviations of strip material including alloyed metal strip. The gauge includes a radiation source for emitting a beam of material-penetrating radiation, a detector circuit for sensing the radiation, a meter for indicating deviations in strip thickness from a nominal thickness and a standards magazine for selectively inserting elements of different standard thicknesses into the beam. The composite thickness of standards is made equal to the nominal thickness for all values within a given measurement range. Compensation for alloy constituents in the strip and an accurate correlation between meter readings and a range of thickness variations are automatically provided. With one or more standards in the beam, the meter is nulled to the nominal thickness of the strip by signals developed and fed back to adjust, for example, the source radiation level. A second calibration is then effected by adding other standards corresponding to the anticipated range of thickness variations and repeatedly adjusting the detector circuit gain to yield an accurate correlation between a meter reading and a value of strip thickness in that range. These gain adjustments are performed until a predetermined sensitivity to thickness variations is obtained.
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