Instron Limited

Robert F Mockapetris

Fred L Lehman

Circuitry that is used to determine the strain of a component and includes a waveform random access memory that stores excitation digital data that represent values of an excitation waveform, a digital-to-analog converter to convert the digital data to an analog excitation signal, a strain sensing transducer that receives the excitation signal and generates an analog response signal, an analog-to-digital converter that digitizes the transducer response signal, a demodulator that multiplies the digital response signal times phase adjusted values of the excitation digital data stored in the waveform memory and low-pass filters the digital response signal, and a resistance-to-voltage converter connected to present a voltage indicating the resistance of an identifying resistor to the analog-to-digital converter. Also disclosed are the use of a serial data transmission line to transmit multiplexed excitation waveform data from a host to a plurality of slave sensor conditioning boards and a calibration technique for calculating a phase shift angle for the demodulator.

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Weymouth, MA, United States of America

Robert F Mockapetris