CN-121995124-A - Diagnostic device, diagnostic method and field device

Abstract

The present disclosure provides a diagnostic apparatus including a generation circuit that generates an inspection signal that is an alternating current signal of a single frequency, a conversion circuit that converts a response signal of a piezoelectric element in response to the inspection signal into a direct current signal, and a controller that analyzes the direct current signal and determines whether the piezoelectric element is operating normally based on the analysis of the direct current signal.

Inventors

• KONDO KOHEI
• Chuan yuan Tuo also
• YOSHIDA FUMIHIRO

Assignees

• 横河电机株式会社

Dates

Publication Date

20260508

Application Date

20211022

Priority Date

20201022

Claims (13)

1. 1. A field device, comprising: A generation circuit that generates an inspection signal that is an alternating current signal of a single frequency, A conversion circuit for converting a response signal of the piezoelectric element in response to the inspection signal into a DC signal, and A controller that: analyzing the DC signal, and Determining a health of the piezoelectric element based on the analysis of the direct current signal, wherein The controller determines the health of the piezoelectric element by analyzing the direct current signal and calculating a capacitance value of the piezoelectric element.
2. 2. The field device of claim 1, wherein the conversion circuit comprises a half-wave rectifier.
3. 3. The field device according to claim 1 or 2, wherein the inspection signal is an alternating current signal whose frequency does not belong to a frequency band of an electric signal according to a physical quantity output from the piezoelectric element.
4. 4. The field device of any of claims 1-3, wherein the controller is further to: Analyzing the direct current signal to calculate a capacitance value of the piezoelectric element; Comparing the capacitance value with a predetermined standard value, and Based on the result of the comparison, the health of the piezoelectric element is determined.
5. 5. The field device of any of claims 1-3, wherein the controller is further to: analyzing the DC signal to calculate a capacitance value of the piezoelectric element, and An expected failure time for the piezoelectric element is determined based on the calculated capacitance value and a previously calculated capacitance value.
6. 6. The field device of claim 5, wherein the controller determines a predicted time to failure for the piezoelectric element as the health condition based on a slope of a graph showing a change in a previously calculated capacitance value of the piezoelectric element.
7. 7. The field device of claim 5, wherein the controller determines a predicted failure time for the piezoelectric element as the health condition based on a slope or a changing average of a graph showing changes in previously calculated capacitance values of a plurality of the piezoelectric elements.
8. 8. The field device of any one of claims 1 to 7, further comprising: a memory storing information related to a physical quantity measured by the piezoelectric element, wherein, The controller, in response to receiving an electric signal corresponding to a physical quantity output from the piezoelectric element, causes the memory to store a measured value of the physical quantity calculated based on the electric signal, and The controller outputs the measured value stored in the memory immediately before determining the health of the piezoelectric element while determining the health of the piezoelectric element.
9. 9. The field device of any one of claims 1 to 8, wherein the controller is further to: Controlling operation of at least one of the generating circuit or the converting circuit; changing a parameter associated with the operation while analyzing the direct current signal; The health of the piezoelectric element is determined based on the changed parameter.
10. 10. The field device of any one of claims 1 to 9, further comprising: a resistor located between the generating circuit and the piezoelectric element, wherein, The controller: Calculating an insulation resistance value of the piezoelectric element based on a diagnostic reference voltage, an output signal of the piezoelectric element with respect to the diagnostic reference voltage, and a resistance value of the resistor when the diagnostic reference voltage is applied from the generating circuit to the piezoelectric element via the resistor, and The health of the piezoelectric element is determined based on the insulation resistance value.
11. 11. The field device of any one of claims 1 to 10, comprising a plurality of piezoelectric elements, wherein, The controller selects one piezoelectric element from the plurality of piezoelectric elements and determines a health condition of the piezoelectric element.
12. 12. The field device of claim 8, further comprising a display device, wherein the display device displays the measurement output by the controller.
13. 13. A diagnostic method comprising: Generating an inspection signal, wherein the inspection signal is a single-frequency alternating current signal; converting a response signal of the piezoelectric element in response to the inspection signal into a direct current signal, and Analyzing the DC signal and determining the health of the piezoelectric element, wherein The determination of the health of the piezoelectric element is performed based on analyzing the direct current signal and calculating a capacitance value of the piezoelectric element.

Description

Diagnostic device, diagnostic method and field device Cross Reference to Related Applications The application is a divisional application of an application patent application with the application date of 2021, 10-month 22, the application number of 202111232797.4 and the application name of diagnostic equipment, diagnostic method and field equipment. Technical Field The present invention relates generally to a diagnostic device, a diagnostic method, and a field device. Background It is well known that field devices (e.g., vortex flowmeters) use piezoelectric elements that convert a physical quantity, such as oscillation, pressure, etc., into a voltage. In such field devices, in general, the piezoelectric element is typically disposed inside the field device. Therefore, there is a need to be able to diagnose whether a piezoelectric element is operating properly without removing the piezoelectric element from the field device. Patent document 1 describes a configuration concerning diagnosis of a piezoelectric element. Patent literature Patent document 1 JP 2005-526228A (translation of PCT application) However, in the configuration according to patent document 1, since an alternating current signal is applied to the piezoelectric element at least two different frequencies and the response thereof is measured, the circuit configuration is complex and large-scale. Disclosure of Invention One or more embodiments of the present invention provide a diagnostic device and a diagnostic method and a field device capable of diagnosing the health of a piezoelectric element using a simple configuration. The diagnostic apparatus according to several embodiments is provided with a generating circuit for generating an inspection signal that is an alternating current signal of a single frequency, a converting circuit for converting a response signal of a piezoelectric element in response to the inspection signal into a direct current signal, and a control section for analyzing the direct current signal to determine a health condition of the piezoelectric element. In particular, the conversion circuit may be provided with a half-wave rectifier. Accordingly, the diagnosis apparatus applies a single-frequency alternating current signal to the piezoelectric element and measures the response thereof, so that the health condition of the piezoelectric element can be diagnosed with a simple configuration. In the diagnostic apparatus according to one or more embodiments, the generating circuit generates, as the inspection signal, an alternating-current signal whose frequency does not belong to a frequency band of the electric signal according to the physical quantity output from the piezoelectric element. Therefore, in the case where the inspection signal does not affect the electric signal corresponding to the physical quantity output from the piezoelectric element, the diagnostic apparatus analyzes the direct current signal reflecting the response of the piezoelectric element in response to the inspection signal, and determines the health of the piezoelectric element with respect to the capacitance. In the diagnostic apparatus according to one or more embodiments, the control section analyzes the direct current signal to calculate a capacitance value of the piezoelectric element, and compares the capacitance value with a predetermined standard value to determine whether the piezoelectric element is operating normally as a health condition of the piezoelectric element. Therefore, the diagnostic apparatus can easily and accurately determine whether the piezoelectric element is operating normally. In the diagnostic apparatus according to one or more embodiments, the control section analyzes the direct current signal to calculate a capacitance value of the piezoelectric element, and determines an expected failure time with respect to the piezoelectric element as a health condition based on the calculated capacitance value of the piezoelectric element and a previously calculated capacitance value. Therefore, the diagnostic apparatus can predict the malfunction of the piezoelectric element based on past data. The diagnostic apparatus according to one or more embodiments is further provided with a storage section for storing information related to a physical quantity measured by the piezoelectric element, wherein the control section, in response to receiving an electric signal corresponding to the physical quantity output from the piezoelectric element, causes the storage section to store a measured value of the physical quantity calculated based on the electric signal, and outputs the measured value stored in the storage section immediately before the health condition of the piezoelectric element is determined while the health condition of the piezoelectric element is determined. Therefore, even while the health state of the piezoelectric element is determined, the measured value of the physical quantity obtained by using the piezoelectri