Plate coating thickness measurement device - has signal processing and sensitivity correction circuits ensuring uniform sensitivity over all ranges

摘要

A coating thickness measuring device is esp. for dielectric, non-magnetic, electrically conducting materials etc. It is applicable to plate coating regulation in metallurgy and industrial machine mfr., e.g. for corrosion protection. It ensures uniform sensitivity over all measurement regions, eliminates region boundary null drift, and guarantees a high degree of measurement accuracy. A thickness detector electrical output is fed to a circuit converting it into an electrical signal proportional to thickness. Thickness detector output signals are fed to a peak detector driving a subtractor and a measurement range switch. A reference voltage is connected to the other switch input and the switch output drives the other subtractor input. The subtractor and range switch drive a sensitivity correction circuit. The thickness proportional signal is produced by a summer adding the range switch output and the correction circuit output.