Abstract: A field device (10) includes a sensor (11) that measures a physical quantity and outputs a measurement signal indicating a measured value, converters (12, 15, 16) that perform a predetermined conversion process on the measurement signal, and a processor (17) that outputs an output signal corresponding to the measurement signal subjected to the conversion process. The processor (17) starts verifying operational soundness of the converters (12, 15, 16) when the measurement signal subjected to the conversion process satisfies a predetermined condition, and outputs, while the operational soundness of the converters (12, 15, 16) is being verified, a signal corresponding to the measurement signal subjected to the conversion process and acquired immediately before the operational soundness of the converters (12, 15, 16) is verified, or a signal corresponding to the measurement signal indicating a predetermined measured value of the sensor (11), as the output signal.

Abstract: A field device includes: a current controller configured to operate with a first power supply voltage and output a control signal for controlling a current to be output to a transmission line; a current output unit configured to operate with a second power supply voltage different from the first power supply voltage, the current output unit being capable of outputting a current of a magnitude corresponding to the control signal output from the current controller to the transmission line; and an abnormality notification unit configured to output, to the current output unit, a first signal for causing the current output unit to output a burnout current indicating that an abnormality has occurred in a case in which an abnormality occurs in the first power supply voltage.

Abstract: A field device (10) includes a sensor (11) that measures a physical quantity and outputs a measurement signal indicating a measured value, converters (12, 15, 16) that perform a predetermined conversion process on the measurement signal, and a processor (17) that outputs an output signal corresponding to the measurement signal subjected to the conversion process. The processor (17) starts verifying operational soundness of the converters (12, 15, 16) when the measurement signal subjected to the conversion process satisfies a predetermined condition, and outputs, while the operational soundness of the converters (12, 15, 16) is being verified, a signal corresponding to the measurement signal subjected to the conversion process and acquired immediately before the operational soundness of the converters (12, 15, 16) is verified, or a signal corresponding to the measurement signal indicating a predetermined measured value of the sensor (11), as the output signal.

Abstract: A diagnostic device includes: a generation circuit that generates an inspection signal that is an alternating current signal of a single frequency, a conversion circuit that converts, into a direct current signal, a response signal of a piezoelectric element in response to the inspection signal, and a controller that analyzes the direct current signal and determines whether the piezoelectric element operates normally based on the analysis of the direct current signal.

Abstract: A field device includes: a current controller configured to operate with a first power supply voltage and output a control signal for controlling a current to be output to a transmission line; a current output unit configured to operate with a second power supply voltage different from the first power supply voltage, the current output unit being capable of outputting a current of a magnitude corresponding to the control signal output from the current controller to the transmission line; and an abnormality notification unit configured to output, to the current output unit, a first signal for causing the current output unit to output a burnout current indicating that an abnormality has occurred in a case in which an abnormality occurs in the first power supply voltage.