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Abstract

An industrial process field device includes a piezoelectric transducer, a sensor circuit, a test circuit, a controller and a communications circuit. The sensor circuit generates a sensor signal indicating a process variable based on a voltage across the piezoelectric transducer. The test circuit is configured to apply a voltage pulse having a pulse voltage to the piezoelectric transducer that induces a response signal, and capture peak positive and negative voltages of the response signal. The controller calculates a current condition value of the piezoelectric transducer based on the peak positive voltage, the peak negative voltage and the pulse voltage, and generates a diagnostic test result based on a comparison of the current condition value to a reference condition value corresponding to a properly operating piezoelectric transducer. The communications circuit communicates the process variable and the diagnostic test result to an external control unit over a process control loop.

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