Method for diagnosing faults in intelligent valve positioners

Abstract

The present application relates to the technical field of data analysis, and particularly relates to a fault diagnosis method of an intelligent valve positioner, which solves the technical problem of low accuracy of fault diagnosis in the prior art. The method comprises: after valve adjustment, obtaining monitoring data of the valve during the last multiple adjustments; the monitoring data comprises actual valve flow before and after adjustment, set valve flow, and valve dead zone value during adjustment; the valve dead zone value is used to represent the response hysteresis interval of the valve actuator to the control instruction; according to the difference between the actual valve flow before and after adjustment and the set valve flow, and the change rule of the valve dead zone value, the necessity of the valve fault alarm is determined; the necessity of the valve fault alarm is used to represent the emergency degree of maintenance inspection of the valve actuator; and the valve is diagnosed according to the necessity of the valve fault alarm.

Description

Technical Field

[0001] This invention relates to the field of data analysis technology, and more specifically to a fault diagnosis method for intelligent valve positioners. Background Technology

[0002] In industrial production, valves, as core components of fluid control, directly impact production continuity, safety, and economy. Intelligent valve positioners, as key equipment in valve control, enable precise control and status monitoring of valve actuators. They prevent unplanned downtime through fault warnings, avoid safety accidents, improve production continuity, and optimize maintenance plans based on data, achieving cost reduction, efficiency improvement, and refined asset management.

[0003] Currently, industry-wide fault diagnosis for intelligent valve positioners largely relies on the difference between the valve's set flow rate and the actual flow rate. However, this traditional monitoring method has certain limitations. In actual production processes, external interference factors such as fluctuations in the gas supply system pressure and insufficient gas volume can cause deviations between the valve's set flow rate and the actual flow rate, and even sudden changes in the dead zone value. If judgment is based solely on flow rate differences, external interference can easily be misjudged as mechanical failures of the actuator, resulting in low accuracy in fault diagnosis. It also fails to effectively distinguish between internal valve wear and external gas source problems, thus affecting the reliability of maintenance decisions. Summary of the Invention

[0004] To address the problem of low accuracy in fault diagnosis in existing technologies, the present invention aims to provide a fault diagnosis method for intelligent valve positioners, and the specific technical solution adopted is as follows:

[0005] This application provides a fault diagnosis method for an intelligent valve positioner, including:

[0006] After the valve is adjusted, monitoring data of the valve during the most recent adjustments is acquired; the monitoring data includes the actual flow rate and set flow rate of the valve before and after adjustment, as well as the valve dead zone value during adjustment; the valve dead zone value is used to characterize the hysteresis range of the valve's actuator in response to control commands;

[0007] Based on the difference between the actual flow rate and the set flow rate of the valve before and after the adjustment, as well as the change pattern of the valve dead zone value, the necessity of the valve's fault alarm is determined; the necessity of the fault alarm is used to characterize the urgency of the valve's actuator requiring maintenance and inspection.

[0008] The valve is diagnosed based on the required fault alarm level.

[0009] In some embodiments, the method includes:

[0010] Obtain the valve set flow rate before and after each most recent adjustment through the valve controller;

[0011] The differential pressure transmitter measures the medium pressure difference of the valve before and after each recent adjustment, and calculates the actual flow rate of the valve before and after each adjustment by combining the valve flow coefficient and the medium specific gravity parameter.

[0012] By sampling and statistically analyzing the valve position control signal and valve position feedback signal during each recent adjustment, the valve dead zone value during each adjustment is calculated.

[0013] In some embodiments, the method includes:

[0014] Based on the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, as well as the valve dead zone value at the time of the current adjustment and the previous adjustment, the numerical anomaly of the valve at the current adjustment is determined; the numerical anomaly is used to characterize the degree to which the operating state of the valve after the current adjustment deviates from the normal operating state.

[0015] The numerical anomaly degree is corrected based on the valve dead zone value during the most recent adjustments to obtain the valve's fault alarm necessity degree.

[0016] In some embodiments, the method includes:

[0017] Based on the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, and the change between the actual flow rate and the set flow rate of the valve after the current adjustment, the numerical mismatch degree of the valve in the current adjustment is determined; the numerical mismatch degree is used to characterize the degree of lag in the response of the actual flow rate of the valve to the change in the set flow rate of the valve.

[0018] The numerical anomaly of the valve in the current adjustment is determined based on the valve dead zone value at the current adjustment and the previous adjustment, as well as the numerical mismatch.

[0019] In some embodiments, the method includes:

[0020] The valve dead zone change rate during the current adjustment is determined based on the valve dead zone value during the current adjustment and the previous adjustment.

[0021] The numerical anomaly of the valve during the current adjustment is determined based on the valve dead zone value, the rate of change of the valve dead zone, and the numerical mismatch.

[0022] In some embodiments, the method includes:

[0023] The interference parameter is determined based on the valve dead zone value during the most recent adjustments of the valve; the interference parameter is used to characterize the degree of interference affecting the monitoring data.

[0024] The numerical anomaly degree is corrected based on the disturbance degree parameter to obtain the fault alarm necessity degree of the valve.

[0025] In some embodiments, the method includes:

[0026] Based on the valve dead zone values ​​during the most recent adjustments, determine the valve dead zone change value for each adjustment;

[0027] A positive change set is constructed based on the valve dead zone change value during each adjustment, and the valve dead zone change rate during each adjustment in the positive change set is determined; the positive change set includes the valve dead zone change values ​​that are positive in the most recent adjustments;

[0028] A difference analysis is performed on the rate of change of valve dead zone during each adjustment in the positive change set to determine the disturbance parameter.

[0029] In some embodiments, the method includes:

[0030] If the interference parameter is less than the preset interference threshold, determine the average rate of change of the valve dead zone change rate during each adjustment in the positive change set;

[0031] The numerical anomaly degree is corrected based on the disturbance degree parameter and the average rate of change to obtain the fault alarm necessity degree of the valve.

[0032] In some embodiments, the method includes:

[0033] If the fault alarm necessity is greater than the alarm threshold, it is determined that the valve actuator has malfunctioned.

[0034] In some embodiments, the method further includes:

[0035] Send fault alarm information; the fault alarm information includes the valve dead zone value when the valve is currently adjusted, the actual flow rate of the valve after the current adjustment, and the necessity of the fault alarm.

[0036] The present invention has the following beneficial effects:

[0037] Based on the above technical solution, this application can acquire monitoring data including actual flow rate, set flow rate, and dead zone value after the valve is adjusted. By comprehensively analyzing the flow rate difference and dead zone value change pattern, the necessity of a fault alarm can be determined. This effectively distinguishes between gas supply system interference and actual actuator malfunctions, and then diagnoses the valve based on the required fault alarm. The above technical solution can effectively identify flow deviations caused by external interference such as gas supply pressure fluctuations, solving the technical problem of insufficient diagnostic accuracy in traditional methods and improving the accuracy and timeliness of fault warnings for intelligent valve positioners. Attached Figure Description

[0038] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart illustrating a fault diagnosis method for an intelligent valve positioner provided in one embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the hardware structure of a fault diagnosis device for an intelligent valve positioner provided in one embodiment of the present invention. Detailed Implementation

[0041] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the fault diagnosis method for the intelligent valve positioner proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0043] In all division and logarithmic operations covered in this application, a smoothing mechanism is employed to prevent computer program crashes or invalid values ​​from being generated due to a zero denominator or a zero input. Specifically, a positive correction factor is superimposed on the denominator term of the division operation or the argument term of the logarithmic function. For example, the value is This ensures the robustness and feasibility of the algorithm under extreme conditions.

[0044] The normalization function mentioned in this application Unless otherwise specified, all values ​​are normalized using maximum and minimum values. The maximum and minimum values ​​are preset empirical extreme values ​​derived from a large amount of historical experimental data. If the calculated result exceeds the [0,1] interval, it is restricted to the [0,1] range by a truncation function (i.e., if the result is less than 0, it is taken as 0, and if it is greater than 1, it is taken as 1) to eliminate the influence of outliers on the evaluation index.

[0045] The specific scheme of the fault diagnosis method for the intelligent valve positioner provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Please see Figure 1 The diagram illustrates a method flowchart for fault diagnosis of an intelligent valve positioner according to an embodiment of the present invention, which includes the following steps:

[0047] Step 101: After valve adjustment, obtain monitoring data of the valve during the most recent adjustments.

[0048] The monitoring data includes the actual valve flow rate and the valve set flow rate before and after adjustment, as well as the valve dead zone value during adjustment. The valve dead zone value is used to characterize the hysteresis range of the valve actuator's response to control commands.

[0049] It should be noted that valve adjustment in this application refers to the modification operation of step change or continuous adjustment of valve flow setpoint according to production needs. "Recent adjustments" typically refers to the current adjustment and the previous 2-10 consecutive adjustments (for example, it can be set to the most recent 5 adjustments; the specific number can be flexibly set according to the complexity of the production process and the requirements for data reliability). Acquiring monitoring data is the foundation of fault diagnosis. By collecting these dynamic parameters in real time, the response characteristics of the valve actuator under different operating conditions can be comprehensively reflected.

[0050] Among them, the valve set flow rate refers to the flow rate value that the valve is expected to achieve as preset by the valve controller, the valve actual flow rate refers to the flow rate value that the valve actually outputs during operation, and the valve dead zone value is a key parameter characterizing the response hysteresis characteristics of the actuator. Specifically, it refers to the range of set value changes in which the actual flow rate does not produce an observable response (or the response does not exceed the noise band) when the flow set value undergoes a step change. It comprehensively reflects the influence of factors such as valve mechanical dead zone, actuator hysteresis, and process disturbances.

[0051] In one possible implementation, this application can obtain the valve set flow rate before and after each most recent adjustment through the valve controller, measure the medium pressure difference of the valve before and after each most recent adjustment through the differential pressure transmitter, and calculate the actual valve flow rate before and after each adjustment by combining the valve flow coefficient and the medium specific gravity parameter. By sampling the valve position control signal and valve position feedback signal at each most recent adjustment and performing statistical analysis, the valve dead zone value at each adjustment can be calculated.

[0052] The valve controller is the core control unit of the intelligent valve positioner, and it stores the set flow parameters for each adjustment. During valve adjustment, the controller records the set flow before adjustment (i.e., the target flow value of the valve before adjustment) and the set flow after adjustment (i.e., the new target flow value). This data can be directly read through the controller's communication interface (such as RS485, HART, etc.). The data acquisition process is simple, accurate, and does not interfere with valve operation.

[0053] Differential pressure transmitters are installed across the valve to measure the pressure difference of the medium in real time, accurately reflecting the flow state of the medium. The valve flow coefficient is a design parameter provided by the valve manufacturer and characterizes the valve's rated flow capacity. The specific gravity of the medium is the relative gravity of the transported medium to water and is preset according to the type of medium being transported.

[0054] For example, taking the adjusted actual flow rate of the valve as an example, the actual flow rate of the valve satisfies the following formula:

[0055]

[0056] in, The actual flow rate of the valve after adjustment. This is the valve flow coefficient. The matching flow coefficient (dimensionless) corresponds to the adjusted valve opening degree. This matching flow coefficient is obtained by querying or calculating the valve's preset flow characteristic curve. This application can use the preset flow characteristic curve data of the valve (provided by the valve manufacturer, usually a table or fitting formula relating valve opening degree and matching flow coefficient). When the valve opening degree... (Unit: %) Once determined, the matching flow coefficient for that opening degree can be obtained by looking up a table or substituting it into the fitting formula. The adjusted valve's medium pressure differential, This refers to the specific gravity of the medium. The calculation method for the actual flow rate of the valve before adjustment is the same and will not be repeated here.

[0057] The valve position control signal is the desired valve opening signal (in %) output by the positioner, while the valve position feedback signal is the actual valve opening signal (in %) measured by a high-resolution non-contact magnetoresistive sensor with a sampling frequency in the millisecond range (for example, the sampling period is 10ms), ensuring that the valve's rapid response process can be captured.

[0058] In some embodiments, when the flow setpoint undergoes a step change, this application can statistically analyze the control signal change range from the start of the control signal change to the point where the feedback signal produces an observable response (response amplitude exceeding the noise band, e.g., the noise band is ±0.1%). Specifically, the dead zone value is calculated using a statistical fitting method by analyzing the time lag and amplitude difference between the control signal and the feedback signal. When the flow setpoint undergoes a step change, this application can record the changes in the control signal and the valve position feedback signal over time. At this time, the control signal changes from its initial steady-state value until it reaches the new setpoint. The feedback signal responds from its initial value. From the initial moment when the control signal begins to change, the response moment when the feedback signal begins to respond is determined, and the difference between the response moment and the initial moment is determined as the dead zone value. For example, if the control signal steps from 50% to 60%, and the feedback signal only begins to respond when the control signal reaches 52%, then the dead zone value is 2%.

[0059] Step 102: Based on the difference between the actual flow rate and the set flow rate of the valve before and after adjustment, as well as the change pattern of the valve dead zone value, determine the necessity of the valve fault alarm.

[0060] Among them, the fault alarm necessity level is used to characterize the urgency of the valve actuator requiring maintenance and inspection.

[0061] It should be noted that the difference in flow rate before and after adjustment reflects the accuracy of the valve's response to changes in the setpoint, while the change pattern of the dead zone reflects the gradual state of mechanical wear and aging of the actuator. Combining these two factors can effectively distinguish between current actuator malfunctions and abnormalities caused by external interference. A higher fault alarm necessity level indicates a higher risk of actuator malfunction and a greater urgency for maintenance and inspection.

[0062] In some embodiments, actuator malfunctions (such as valve stem jamming, spring fatigue, etc.) typically manifest as a continuous increase in flow response deviation and a gradual change in dead zone value, while anomalies caused by external disturbances (such as fluctuations in gas supply pressure) manifest as abrupt and irregular changes in flow deviation and dead zone value. Therefore, based on the above characteristics, this application can effectively filter interference by integrating the features of the two types of parameters, making the calculation of fault alarm necessity more consistent with the actual fault state and avoiding misjudgment.

[0063] Step 103: Perform fault diagnosis on the valve according to the necessity of the fault alarm.

[0064] Fault diagnosis can be achieved by comparing the necessity of a fault alarm with an alarm threshold, and the presence of a fault in the actuator can be determined based on the alarm threshold. The setting of the alarm threshold needs to be combined with the valve type, application scenario, and industrial safety requirements. For example, the alarm threshold can be set to 0.7. This threshold can be calibrated through a large amount of experimental data to achieve a balance between avoiding the omission of serious faults and reducing unnecessary warnings.

[0065] In one possible implementation, if the fault alarm necessity is greater than the alarm threshold, it is determined that the valve actuator has malfunctioned.

[0066] When the fault alarm necessity is greater than the alarm threshold, it indicates that the actuator has a high risk of failure (such as valve stem jamming, spring fatigue, etc.). If maintenance is not carried out in time, the failure may be aggravated and affect production safety. When the fault alarm necessity is less than or equal to the alarm threshold, it indicates that the actuator is operating normally or the risk of failure is low and no immediate maintenance is required.

[0067] In some embodiments, the alarm threshold can be flexibly adjusted according to the actual application scenario. For example, in chemical scenarios with extremely high safety requirements, the threshold can be adjusted to 0.6 to trigger the alarm earlier; in ordinary water supply scenarios, the threshold can be adjusted to 0.8 to reduce unnecessary maintenance.

[0068] In some embodiments, this application may also send fault alarm information.

[0069] The fault alarm information includes the valve dead zone value at the time of the current valve adjustment, the actual flow rate of the valve after the current adjustment, and the necessity of the fault alarm.

[0070] When the microprocessor of the intelligent valve positioner determines that the necessity of the fault alarm is greater than the alarm threshold, it sets the actuator alarm bit in the internal register (the binary bit changes from 0 to 1) and updates the stored data such as the dead zone value at the time of adjustment, the actual flow rate after the current adjustment, and the necessity of the fault alarm. Then, it packages and sends the alarm information to the industrial control system through digital communication protocols (such as HART, Profibus PA). After the gateway of the control system unpacks the alarm, it notifies the operator in the form of sound and light (such as pop-up window, flashing red light, buzzer alarm) to ensure that the operator receives the alarm information in a timely manner.

[0071] For example, the alarm message format is: "Valve No.: V-001; Current Dead Zone Value: 3.2%; Current Actual Flow Rate: 15.6 m³ / h; Fault Alarm Necessity: 0.85; Alarm Level: Emergency; Recommended Action: Immediately stop the machine and check the actuator", enabling the operator to quickly grasp the key information and take corresponding measures.

[0072] Based on the above technical solution, this application can acquire monitoring data including actual flow rate, set flow rate, and dead zone value after the valve is adjusted. By comprehensively analyzing the flow rate difference and dead zone value change pattern, the necessity of a fault alarm can be determined. This effectively distinguishes between gas supply system interference and actual actuator malfunctions, and then diagnoses the valve based on the required fault alarm. The above technical solution can effectively identify flow deviations caused by external interference such as gas supply pressure fluctuations, solving the technical problem of insufficient diagnostic accuracy in traditional methods and improving the accuracy and timeliness of fault warnings for intelligent valve positioners.

[0073] As a possible embodiment of this application, step 102 above can be implemented through the following steps:

[0074] Step 201: Based on the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, as well as the valve dead zone value during the current adjustment and the previous adjustment, determine the numerical abnormality of the valve during the current adjustment.

[0075] The numerical anomaly degree characterizes the extent to which the valve deviates from its normal operating state after adjustment. A higher anomaly degree indicates a more severe deviation from normal operation. The determination of the numerical anomaly degree comprehensively considers both the matching degree of the flow response and the absolute change in the dead zone value. When a valve experiences faults such as stem jamming, sticking, excessively tight or worn packing glands, or actuator spring fatigue or breakage, not only will the actual flow rate differ from the set value, but it will also cause an abnormal increase in the dead zone value. Therefore, this application, by combining these two types of parameters for analysis, can more accurately identify the abnormal state of the actuator.

[0076] Step 202: Correct the numerical anomaly degree based on the valve dead zone value during the most recent adjustments to obtain the valve fault alarm necessity degree.

[0077] Since external interference (such as gas supply pressure fluctuations) may affect the numerical anomaly, this application can correct the numerical anomaly by using the valve dead zone value, thereby eliminating the influence of external interference and making the final fault alarm necessity more consistent with the actual fault state of the actuator.

[0078] In some embodiments, this application can utilize the changing patterns of dead zone values ​​during multiple adjustments to identify and eliminate the impact of external disturbances such as gas supply system malfunctions. Since mechanical failures of actuators typically manifest as a gradual and unidirectional increase in dead zone values, while disturbances such as gas supply pressure fluctuations manifest as random and bidirectional changes in dead zone values, analyzing historical change patterns can effectively distinguish between these two situations, thereby reasonably correcting numerical anomalies and avoiding misjudgments.

[0079] Based on the above technical solution, this application can determine the numerical anomaly degree of the valve in the current adjustment based on the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, as well as the valve dead zone value during the current adjustment and the previous adjustment, to reflect the current instantaneous state of the valve. Then, based on the valve dead zone values ​​during the most recent adjustments, the numerical anomaly degree is corrected to obtain the fault alarm necessity degree of the valve. This hierarchical calculation method considers both the current operating conditions and the influence of historical trends, thereby effectively distinguishing between the performance degradation of the actuator itself and external system interference, improving the accuracy of fault alarm necessity degree calculation, and reducing the false alarm rate.

[0080] As a possible embodiment of this application, step 201 above can be implemented through the following steps:

[0081] Step 301: Determine the degree of numerical mismatch of the valve under the current adjustment based on the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, as well as the difference between the actual flow rate and the set flow rate of the valve after the current adjustment.

[0082] Among them, the numerical mismatch degree is used to characterize the degree of lag in the response of the actual flow rate of the valve to changes in the valve's set flow rate.

[0083] For example, the numerical mismatch degree satisfies the following formula:

[0084]

[0085] in, For the first The degree of numerical mismatch during the next adjustment. For the first The absolute value of the difference between the valve's set flow rate and its actual flow rate after the adjustment. The maximum absolute value of the difference between the set flow rate and the actual flow rate of the valve across all historical adjustments is selected. For the first The valve set flow rate before the adjustment. For the first The valve set flow rate after the second adjustment. For the first Actual valve flow rate before the adjustment For the first The actual flow rate of the valve after the second adjustment. It is a safety parameter used to correct for fractions where the denominator is 0; its dimension is flow rate. The specific value can be determined according to The value of the value determines the outcome. The specific value can be determined according to The value of the value determines the outcome, such as It can be .

[0086] This reflects the ratio of the current flow deviation to the historical maximum deviation; a larger ratio indicates a more significant current flow deviation. Reflects the adjustment range of the set flow rate. The response magnitude reflects the actual traffic flow. It reflects the actual rate of change; ideally, the actual rate of change should be 1. This indicates the degree to which the actual rate of change deviates from the ideal value of 1. The larger the value, the greater the deviation of the actual flow rate from the set change (whether it fails to reach or exceeds the set change). The larger the current flow rate deviation, the larger the set flow rate adjustment range, and the smaller the actual flow rate response range. The larger.

[0087] Step 302: Determine the numerical abnormality of the valve in the current adjustment based on the valve dead zone value and numerical mismatch degree during the current adjustment and the previous adjustment.

[0088] In one possible implementation, this application can determine the valve dead zone change rate during the current adjustment based on the valve dead zone value during the current adjustment and the valve dead zone value during the previous adjustment. Then, it can determine the numerical anomaly degree of the valve during the current adjustment based on the valve dead zone value during the current adjustment, the valve dead zone change rate, and the numerical mismatch degree.

[0089] For example, the numerical outlier satisfies the following formula:

[0090]

[0091] in, For the first Numerical anomaly at the time of adjustment For the first Valve dead zone value during the next adjustment The preset standard dead zone value (unit: %) is set by the engineer according to the valve type and control requirements (for example, it can be 1%). The maximum permissible safe rate of change is determined through accelerated aging tests and statistical calibration of field operation data, based on the material of the valve actuator, its design life, and the reliability requirements of the industrial application scenario. For example, it can be taken as 0.3% / h under high temperature and high pressure conditions, and 0.5%-0.8% / h under normal conditions. For the first The rate of change of valve dead zone during the first adjustment can be based on the... The valve dead zone change value during the second adjustment and the first The second adjustment and the first The ratio of the interval length of the adjustment is determined, the first The valve dead zone change value during the second adjustment can be the first The second adjustment and the first The absolute value of the difference in valve dead zone values ​​after each adjustment is expressed as follows. For the first The degree of numerical mismatch during the next adjustment. This represents the maximum value of the numerical mismatch across all adjustments. It is a safety parameter used to correct fractions where the denominator is 0. Dimensions and The same applies; the specific value can be determined based on... The value of the value determines the outcome. Dimensions and The same applies; the specific value can be determined based on... The value of the value determines the outcome, such as It can be . This is the function for finding the maximum value.

[0092] It reflects the deviation of the current dead zone value from the standard value (a positive value indicates that it exceeds the standard). It reflects the difference between the current rate of change of the dead zone and the historical maximum rate (the smaller the difference, the closer the change is to the maximum rate). This reflects the ratio of the current mismatch to the historical maximum mismatch. A larger dead-zone deviation and a rate of change closer to the maximum rate indicate a higher mismatch. The larger.

[0093] Based on the above technical solution, this application can determine the numerical mismatch degree of the valve in the current adjustment by considering the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, as well as the change in the actual flow rate and the set flow rate of the valve after the current adjustment. Then, based on the valve dead zone value and numerical mismatch degree during the current and previous adjustments, the numerical anomaly degree of the valve in the current adjustment is determined. The numerical mismatch degree directly reflects the control accuracy of the valve, while the dead zone change rate reflects the mechanical wear or loosening of the actuator. Therefore, by analyzing these two dimensions to determine the numerical anomaly degree of the valve in the current adjustment, this application can more sensitively detect signs of actuator performance degradation and improve the ability to identify progressive faults.

[0094] As a possible embodiment of this application, step 202 above can be implemented through the following steps:

[0095] Step 401: Determine the interference parameter based on the valve dead zone value during the most recent valve adjustments.

[0096] Among them, the interference degree parameter is used to characterize the degree of interference affecting the monitoring data.

[0097] It should be noted that performance degradation caused by mechanical wear is typically unidirectional and gradual, meaning the dead zone value increases continuously over time at a relatively stable rate. In contrast, external disturbances such as fluctuations in air pressure exhibit bidirectional randomness, with the dead zone value changing in an unpredictable direction and at a significantly fluctuating rate. Therefore, this application can quantify the impact of such disturbances by analyzing the gradual change pattern of the dead zone value during recent adjustments.

[0098] In one possible implementation, this application can determine the valve dead zone change value for each adjustment based on the valve dead zone value during the most recent adjustments.

[0099] For example, for the most recent N adjustments (e.g., 10), calculate the th adjustment. Next and first The difference in valve dead zone value during the first adjustment is denoted as the first adjustment. Valve dead zone change value during the second adjustment ( The value of is from 2 to N), where For the first Valve dead zone value during the next adjustment For the first Valve dead zone value during the next adjustment.

[0100] Then, a positive change set is constructed based on the valve dead zone change value at each adjustment, and the valve dead zone change rate at each adjustment in the positive change set is determined.

[0101] The positive change set includes valve dead zone changes that are greater than a preset noise threshold during recent adjustments. The preset noise threshold is determined based on the valve positioner's measurement accuracy, control signal resolution, and the dead zone fluctuation range in historical normal operation data. For example, the preset noise threshold could be 0.1%. The positive change set refers to the set of all positive dead zone changes, reflecting the increasing trend of the dead zone value (actuator wear typically manifests as a gradual increase in the dead zone value). For each element in the positive change set, the corresponding dead zone change rate is calculated. ,in For the first Valve dead zone change value during the next adjustment For the first The second adjustment and the first The interval between adjustments.

[0102] It should be noted that if there are no valve dead zone changes with values ​​greater than the preset noise threshold during recent adjustments, this application does not need to perform the calculation of the interference degree parameter. That is, when determining the necessity of the valve fault alarm, it is not necessary to correct the numerical abnormality through the interference degree parameter.

[0103] Thus, this application can perform difference analysis on the rate of change of valve dead zone during each adjustment in the positive change set, and determine the interference parameter.

[0104] For example, the interference parameter satisfies the following formula:

[0105]

[0106] in, For the first The interference parameter during the next adjustment The number of elements in the set undergoing positive change. The first in the set of positive changes The corresponding dead zone change rate is adjusted each time. This represents the average dead zone rate of change for all adjustments in the set of positive changes. This is a normalization function (e.g., maximum / minimum normalization) used to map the calculation results to the range of 0 to 1.

[0107] This reflects the number of times the valve dead zone value increases; the fewer the number of times, the weaker the regularity of the dead zone increase. This reflects the degree of deviation between the rate of change of the dead zone of each valve and the average rate; the greater the deviation, the more irregular the change. The smaller, The greater the deviation, the better. The larger.

[0108] Step 402: Correct the numerical anomaly degree based on the disturbance degree parameter to obtain the valve fault alarm necessity degree.

[0109] This application can determine subsequent correction operations by combining the magnitude of the interference degree parameter and the preset interference degree threshold. When the interference degree parameter is less than the preset interference degree threshold, it indicates that the current anomaly is mainly caused by a failure of the actuator, and further correction is required based on the average dead zone change rate. When the interference degree parameter is greater than or equal to the preset interference degree threshold, it indicates that the current anomaly is caused by external interference, and there is no need to trigger a fault alarm.

[0110] In one possible implementation, this application can determine the average rate of change of the valve dead zone change rate during each adjustment in the positive change set, provided that the interference parameter is less than a preset interference threshold.

[0111] The preset interference threshold can be determined based on experimental testing, for example, it can be set to 0.7. When the interference parameter is less than the preset interference threshold, it is considered that the change in the current dead zone value conforms to the gradual wear characteristics of the actuator, rather than being caused by external interference.

[0112] Subsequently, the numerical anomaly degree is corrected based on the disturbance degree parameter and the mean rate of change to obtain the valve's fault alarm necessity degree.

[0113] For example, the necessity of a fault alarm satisfies the following formula:

[0114]

[0115] in, For the first Necessity of valve fault alarm during the second adjustment For the first Numerical anomaly at the time of adjustment For the first The interference parameter during the next adjustment The maximum value of the numerical anomaly during all adjustments. This represents the average dead zone rate of change for all adjustments in the set of positive changes. A normalization function (e.g., maximum / minimum normalization) is used to map the calculation result to the range of 0 to 1. It is a safety parameter used to correct fractions where the denominator is 0. Dimensions and The same applies; the specific value can be determined based on... The value of the value determines the outcome. Dimensions and The same applies; the specific value can be determined based on... The value of the value determines the outcome, such as It can be .

[0116] This reflects the ratio of the current numerical outlier to the historical maximum numerical outlier. The average rate of increase in dead zone indicates that the higher the rate, the faster the wear. The more severe the current anomaly and the faster the wear rate, the less interference there is. The larger.

[0117] If, during the most recent adjustments, there are no valve dead zone change values ​​with a median value greater than the preset noise threshold (i.e., the set of positive changes is empty), the necessity of the fault alarm satisfies the following formula:

[0118]

[0119] in, For the first Necessity of valve fault alarm during the second adjustment For the first Numerical anomaly at the time of adjustment The maximum value of the numerical anomaly during all adjustments. A normalization function (e.g., maximum / minimum normalization) is used to map the calculation result to the range of 0 to 1. It is a safety parameter used to correct fractions where the denominator is 0. Dimensions and The same applies; the specific value can be determined based on... The value of the value determines the outcome, such as It can be .

[0120] Based on the above technical solution, this application determines the interference parameter according to the valve dead zone value during the most recent adjustments, and then corrects the numerical anomaly based on the interference parameter to obtain the fault alarm necessity of the valve. The above technical solution, by introducing the interference parameter to correct the numerical anomaly, effectively eliminates the influence of external interference such as gas supply system faults on the diagnostic results. By analyzing the regularity and unidirectional characteristics of dead zone value changes, it distinguishes between mechanical wear and external interference, and combines the wear rate and anomaly to calculate the fault alarm necessity, achieving accurate quantitative assessment of actuator fault risk and significantly improving the reliability and practicality of fault early warning.

[0121] It should be noted that the various embodiments of this application can be referenced or learned from each other. For example, the same or similar steps, method embodiments, system embodiments and device embodiments can be referenced from each other without limitation.

[0122] This application embodiment also provides a hardware structure diagram of a fault diagnosis device for an intelligent valve positioner (denoted as fault diagnosis device 20 for intelligent valve positioner), see [link to diagram]. Figure 2 The fault diagnosis device 20 of the intelligent valve positioner includes a processor 21, and optionally, a memory 22 connected to the processor 21.

[0123] In the first possible implementation, see Figure 2The fault diagnosis device 20 for the intelligent valve positioner also includes a communication interface 23. The processor 21, memory 22, and communication interface 23 are connected via a bus. The communication interface 23 is used to communicate with other devices or communication networks. Optionally, the communication interface 23 may include a transmitter and a receiver. The device in the communication interface 23 used to implement the receiving function can be considered as a receiver, which is used to perform the receiving steps in the embodiments of this application. The device in the communication interface 23 used to implement the transmitting function can be considered as a transmitter, which is used to perform the transmitting steps in the embodiments of this application.

[0124] Based on the first possible implementation method Figure 2 The structural diagram shown can be used to illustrate the structure of the fault diagnosis device for the intelligent valve positioner involved in the above embodiments.

[0125] in, Figure 2 The system chip in the fault diagnosis device of the intelligent valve positioner can also be illustrated. In this case, the actions performed by the fault diagnosis device of the intelligent valve positioner can be implemented by the system chip. The specific actions performed can be found above and will not be repeated here.

[0126] In implementation, each step of the method provided in this embodiment can be completed by integrated logic circuits in the processor or by instructions in software form. The steps of the method disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules in the processor.

[0127] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0128] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A fault diagnosis method for an intelligent valve positioner, characterized in that, include: After the valve is adjusted, monitoring data of the valve during the most recent adjustments is acquired; the monitoring data includes the actual flow rate and set flow rate of the valve before and after adjustment, as well as the valve dead zone value during adjustment; the valve dead zone value is used to characterize the hysteresis range of the valve's actuator in response to control commands; Based on the difference between the actual flow rate and the set flow rate of the valve before and after the adjustment, as well as the change pattern of the valve dead zone value, the necessity of the valve's fault alarm is determined; the necessity of the fault alarm is used to characterize the urgency of the valve's actuator requiring maintenance and inspection. The valve is diagnosed based on the required fault alarm level. Specifically, based on the difference between the actual flow rate and the set flow rate of the valve before and after the adjustment, and the changing pattern of the valve dead zone value, the necessity of the valve's fault alarm is determined, including: Based on the difference between the actual flow rate and the set flow rate of the valve before and after the current adjustment, and the change between the actual flow rate and the set flow rate of the valve after the current adjustment, the numerical mismatch degree of the valve in the current adjustment is determined; the numerical mismatch degree is used to characterize the degree of lag in the response of the actual flow rate of the valve to the change in the set flow rate of the valve. The numerical anomaly of the valve in the current adjustment is determined based on the valve dead zone value at the current adjustment and the previous adjustment, as well as the numerical mismatch degree; the numerical anomaly degree is used to characterize the degree to which the valve's operating state after the current adjustment deviates from its normal operating state; The numerical anomaly degree is corrected based on the valve dead zone value during the most recent adjustments to obtain the valve's fault alarm necessity degree.

2. The fault diagnosis method for the intelligent valve positioner according to claim 1, characterized in that, After the valve is adjusted, acquire monitoring data of the valve during the most recent adjustments, including: Obtain the valve set flow rate before and after each most recent adjustment through the valve controller; The differential pressure transmitter measures the pressure difference of the medium before and after each adjustment of the valve, and calculates the actual flow rate of the valve before and after each adjustment by combining the valve flow coefficient and the specific gravity of the medium. By sampling and statistically analyzing the valve position control signal and valve position feedback signal during each recent adjustment, the valve dead zone value during each adjustment is calculated.

3. The fault diagnosis method for the intelligent valve positioner according to claim 1, characterized in that, The numerical anomaly of the valve in the current adjustment is determined based on the valve dead zone value at the current adjustment and the previous adjustment, as well as the numerical mismatch, including: The valve dead zone change rate during the current adjustment is determined based on the valve dead zone value during the current adjustment and the previous adjustment. The numerical anomaly of the valve during the current adjustment is determined based on the valve dead zone value, the rate of change of the valve dead zone, and the numerical mismatch.

4. The fault diagnosis method for the intelligent valve positioner according to claim 1, characterized in that, The numerical anomaly degree is corrected based on the valve dead zone value during the most recent adjustments to obtain the valve's fault alarm necessity degree, including: The interference parameter is determined based on the valve dead zone value during the most recent adjustments of the valve; the interference parameter is used to characterize the degree of interference affecting the monitoring data. The numerical anomaly degree is corrected based on the disturbance degree parameter to obtain the fault alarm necessity degree of the valve.

5. The fault diagnosis method for the intelligent valve positioner according to claim 4, characterized in that, The disturbance parameter is determined based on the valve dead zone value during the most recent adjustments of the valve, including: Based on the valve dead zone values ​​during the most recent adjustments, determine the valve dead zone change value for each adjustment; A positive change set is constructed based on the valve dead zone change value during each adjustment, and the valve dead zone change rate during each adjustment in the positive change set is determined; the positive change set includes the valve dead zone change values ​​that are positive in the most recent adjustments; A difference analysis is performed on the rate of change of valve dead zone during each adjustment in the positive change set to determine the disturbance parameter.

6. The fault diagnosis method for the intelligent valve positioner according to claim 5, characterized in that, Based on the disturbance parameter, the numerical anomaly degree is corrected to obtain the fault alarm necessity degree of the valve, including: If the interference parameter is less than the preset interference threshold, determine the average rate of change of the valve dead zone change rate during each adjustment in the positive change set; The numerical anomaly degree is corrected based on the disturbance degree parameter and the average rate of change to obtain the fault alarm necessity degree of the valve.

7. The fault diagnosis method for the intelligent valve positioner according to claim 1, characterized in that, Based on the required fault alarm level, the valve is diagnosed for faults, including: If the fault alarm necessity is greater than the alarm threshold, it is determined that the valve actuator has malfunctioned.

8. The fault diagnosis method for the intelligent valve positioner according to claim 7, characterized in that, The method further includes: Send fault alarm information; the fault alarm information includes the valve dead zone value when the valve is currently adjusted, the actual flow rate of the valve after the current adjustment, and the necessity of the fault alarm.

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