An apparatus for measuring the displacement in the case of frequency change of an oscillator

摘要

A measuring head (1) measures displacement by variation in frequency of an oscillator due to movement of a core in a coil. The signal from the oscillator is used to gate a high frequency crystal clock (10) into a counter (12). The count is representative of the change in frequency of the oscillator and thus the displacement to be measured. The count is compared by a microprocessor (14) with a look-up table (16) stored in the memory during initial calibration. The operating and processing electronics connected to the sensor head (1) are mounted in a connector which can be directly coupled to connectors of other sensors to form a bus connecting multiple sensors to a host.