Valve regulating device, process plant having a valve regulating device, fault diagnosis method and use of a valve regulating device

Abstract

In a position regulator (31) for a valve regulator (1) of a process plant (100), the position regulator (31) comprises a first signal input (11) for a guiding signal, such as a process regulating signal (p g ) of a process regulator (120) of the process plant (100) and a second signal input for a position actual signal (i) associated with a regulating valve (35), wherein the position regulator (31) is arranged for generating a regulating parameter (g), in particular a gas pressure, for an actuator (33) actuating the regulating valve based on the guiding signal and the position actual signal (i) and comprises a control output for the regulating parameter (g), in particular a gas pressure, it is provided that the position regulator (31) is arranged for calculating an approximation signal (a p ) from the guiding signal by means of a configurable regulator model associated with a specific regulator, in particular the process regulator (120), wherein the regulator model is configured such that a signal generated from the approximation signal (a p ) by the specific regulator corresponds to the guiding signal.

Description

Technical Field

[0001] This article relates to valve control devices used in process equipment such as chemical equipment (e.g., petrochemical equipment), power plants (e.g., nuclear power plants), and food processing equipment (e.g., breweries). This article may particularly relate to process equipment with valve control devices. This article also relates to the use of valve control devices to perform fault diagnosis methods related to process equipment. Background Technology

[0002] Valve regulating devices are typically used in process equipment for cascade process regulation, such as in, for example, in Figure 0 As illustrated in the diagram. In cascaded process control or cascaded regulation, multiple controllers are cascaded, and their respective control loops are nested within each other. Here, the upper level of the control device (1) is at least another process controller (120). The output parameter (p) of the process controller (120) g It is used as a reference parameter for valve regulating devices.

[0003] Typical applications in process control utilize valve control devices with regulating valves to influence subsequent processes for predetermined static or dynamic targets through changes in the volumetric or mass flow. The process controllers used in process control do not directly control the mechanical position of the regulating valves. This is achieved through the regulating electronics of the valve control device in lower-level, cascaded controller stages.

[0004] exist Figure 0 In the example of the regulator cascade, in the upper stage, picture The external control loop is used as an input parameter to provide the process controller (120) with the theoretical process signal (p). g ) and the actual process signal (p) i The process of adjustment formed by the difference between (Regeldifferenz)(p) d The process control method of the process controller (120) can be set to compensate for disturbance parameters affecting the process. Through the control method implemented in the process controller (120), process variability (p) is achieved. e The output parameters generated can be referred to as process control signals (p). g And describe the target position of the control valve (35). Process control signal (p g The signal (i) is provided to the regulating device (1). The valve regulating device (1) also receives a signal (i) representing the actual position of the regulating valve. The position adjuster (31) of the valve regulating device (1) determines the regulating signal (g) from it to control the actuator (33), which may be, for example, a pneumatic or electric regulating drive for the regulating valve. The regulating method of the position adjuster (31) may be set with valve interference parameters to compensate for valve disturbances acting within the valve regulating device.

[0005] EP1451649B1 addresses the identification and differentiation of instabilities within control systems. In the process environment of a valve control system comprising a position controller, actuator, and control valve, it is necessary to identify whether unwanted vibrations are caused by mechanical interference from the actuator connected to the control valve or by misconfiguration of the position controller. To this end, EP1451649B1 proposes obtaining signals within the valve control system and using an estimation unit to determine the presence and source of instabilities. To identify the presence of instabilities, the estimation unit should perform statistical analysis. To identify the cause of the discovered instability, the estimation unit should examine the control loop of the valve control system for the presence of a limiting period, considering the phase angle of the causally related signals. It may also be necessary to determine the timing discrepancy between the control pressure and the valve position to pinpoint the cause of the fault within the control system. The fault diagnosis routines described in EP1451649B1 are generally aimed at identifying the cause of the fault within the control system.

[0006] The effects of disturbances from valve control units combined with upstream process controllers are often insufficiently considered. This makes diagnosing the root cause of problems difficult when multiple control loops cascaded with a single controller exhibit undesirable characteristics. Furthermore, the diagnosis of faults assumed to occur in valve control units may be an artifact of the operating characteristics of the valve control unit highlighted by the process controller. In such cases, it may be useful to provide additional process signals during fault diagnosis of the valve control unit, allowing for the clear identification of the actual cause of the fault.

[0007] US7,085,610B2 ​​relates to an industrial process fault diagnosis device for identifying the source or primary cause of anomalies in an industrial process. Fault diagnosis of process control loops within a process facility should be determined using a primary cause calculation device based on numerous process signals (including process variables, control signals, and fault diagnosis signals) within the process facility. The primary cause calculation device should perform analysis to determine the primary cause of the anomaly, which may be based on control or can be performed using regression learning, fuzzy logic, or neural networks. The primary cause calculation device should be implemented in any process unit of the process facility, such as in a computer within a transmitter, controller, mobile communication device, or central control console. In practice, it has been shown that the process signals required to perform fault diagnosis in conjunction with cascaded control loops to determine the primary cause of a fault are located at most in the upstream process controller. Downstream valve control units are generally not informed of process signals from upstream control loops or other valve control units. Typically, there is not even a communication interface available for transmitting the various process signals. Even if all the necessary interfaces are ready, many process signals may not be available to some valve regulators, especially not in real time, due to the limited available bandwidth in the typical communication networks of process equipment. Summary of the Invention

[0008] Therefore, the objective is to overcome the problems of the prior art, particularly to provide a valve regulating device and / or a fault diagnosis method that allows for the explanation of fault causes, both internal and external, based on a limited number of process signals locally available in the valve regulating device. Thus, a position regulator for a valve regulating device in a process equipment is specified. The position regulator includes a first signal input for a guide signal, particularly a process regulating signal of the process equipment's process regulator. The guide signal can be, in particular, discrete or continuously variable in time. The guide signal can be defined as a timing sequence, wherein the timing sequence particularly includes discrete time-related reference values. The position regulator is configured to generate regulating parameters for the actuator based on the quasi-signal, particularly the process regulating signal, and the actual position signal. These regulating parameters can be, in particular, discrete or continuously variable in time. The valve regulating device particularly includes a position sensor, such as a regulating displacement sensor or a position sensor, which generates an actual position signal based on the actual position of the regulating valve, particularly the valve core or regulating rod of the regulating valve, and provides it to the position regulator.

[0009] The position controller may include position controller electronics and possibly a computer-implemented position controller module. The position controller has a first input for, in particular, an electrical guide signal, and in particular, a process control signal. The position controller may have a second input for, in particular, an actual electrical position signal. The position controller may particularly have a second signal input for an actual position signal regarding the control valve, such as a second signal input for receiving sensor values ​​regarding the absolute or relative position of the control valve. The position controller has an output for outputting a control parameter for an actuator, in particular, an electrical or pneumatic pressure. The output of the position controller may have a digital-to-analog converter or a pneumatic-electric converter. The actuator may be configured to convert the acquired electrical or pneumatic pressure control parameter into a force or torque applied by the actuator to the control valve. The position controller may be configured to generate, in particular, a pneumatic pressure control parameter for an actuator to actuate the control valve based on the guide signal and the actual position signal, and includes a control output for the pneumatic pressure control parameter.

[0010] According to a general alternative, the position regulator is configured to calculate an approximate signal from the pilot signal using a configurable regulator model involving a specific regulator, particularly a process regulator, wherein the regulator model is configured such that the signal generated from the approximate signal by the specific regulator corresponds to the pilot signal. Specifically, it is assumed that the signal and the pilot signal can approximately correspond to each other. The regulator model is particularly decisive. The decisive regulator model can be limited to a clear, unambiguous, and especially reversible association between the pilot signal and the approximate signal.

[0011] According to a particular alternative, the position regulator is also configured to determine an approximate signal from the pilot signal, particularly the process control signal, and the control reversal involved in the process regulator. Additionally, the position regulator is configured to perform at least one fault diagnosis routine taking the approximate signal into account. The approximate signal can be, in particular, discrete or continuously variable in time. The approximate signal can be defined as a timing sequence. The approximate signal can be referred to as a virtual input parameter timing sequence, wherein, in particular, the input parameter timing sequence contains discrete time-dependent input parameter values.

[0012] The position controller may include a computer-implemented reversal module. The position controller, and especially its reversal module, is configured to asymptotically calculate the upstream process controller of the valve control device, considering only the control device signal prepared in the control device. The reversal module may be configured to calculate an approximate signal corresponding to the actual signal of the process controller, which cannot be transmitted from the process controller to the valve control device. For example, the position controller can determine an approximate signal corresponding to the process controller input signal of the process controller, such as the actual process controller signal.

[0013] The position regulator electronics and reversal module can be functionally integrated through a particularly configurable electronic computing and data storage device, such as a microcontroller, within the valve regulating device. The position regulator may include fault diagnosis electronics and / or regulating electronics. The valve regulating device, especially its reversal module, can be specifically designed to perform approximate calculations of the process theory signal or process variability based on the guide signal received by the valve regulating device, particularly the process regulation signal, to determine an approximate signal.

[0014] The fault diagnosis electronics or module for position regulators, especially valve control devices, can then execute fault diagnosis routines that consider the aforementioned approximate signals to, for example, check whether the fault occurs with a certain probability, preferably reliably, within the valve control device or has its cause in a cascaded controller above the valve control device, especially in a process controller. For example, the valve control device can be configured to check whether the approximate signal is within an inconspicuous or conspicuous range, where the latter indicates that the upstream process controller is the source of the fault. The fault diagnosis module, position regulator module, and / or reversal module can be implemented using various at least partially different hardware components, such as various microcontrollers for a single valve control device, or alternatively, using the same hardware, such as a single microcontroller for the valve control device.

[0015] According to one embodiment, the position adjuster includes a memory occupied by process scenario data. The position adjuster may be configured to determine an approximate signal taking into account the process scenario data. Additionally or alternatively, the position adjuster may be configured to execute the at least one fault diagnosis routine taking into account the process scenario data.

[0016] According to one embodiment of the position adjuster, process scenario data can characterize a particularly constant process theoretical signal. According to a first embodiment, process scenario data can characterize the time signal curve of the process theoretical signal and, in particular, the time-constant process theoretical signal. According to an improvement, process scenario data can define a particularly constant process theoretical signal over a certain time period. According to a second embodiment, process scenario data can define a set of specified moments or time periods and the corresponding constant process theoretical signal. According to an alternative design, it is conceivable that process scenario data defines characterization parameters for the process theoretical signal. Characterization parameters can in particular be constant values ​​for the process theoretical signal, the first derivative of the signal curve, or the second derivative of the signal curve. Approximating the process signal using a sinusoidal time curve may be suitable. For a process theoretical signal having a known or assumed sinusoidal curve shape, parameters such as amplitude, frequency, and the offset of the process theoretical signal relative to the actual process signal in the time and / or amplitude dimensions can be defined as those characterized by the process scenario data. For a process theoretical signal having a known or assumed abrupt change curve, parameters such as the abrupt change amplitude and / or the abrupt change time can be defined as those characterized by the process scenario data. Process scenario data can be used to calculate and constrain the regulator structure of the process regulator used in the regulator model, such as a certain PID regulator structure, such as a P regulator structure, I regulator structure, PI regulator structure, PD regulator structure or PID regulator structure, or alternatively other regulator structures such as a two-point regulator structure.

[0017] Position controllers, especially reversing modules, can be configured to determine approximate signals while taking into account process scenario data. For example, a position controller can be configured to perform approximate calculations of process controller droop or actual process signals based on guide signals received by the process controller, especially process control signals, and based on a description of the controller's structure contained in the process scenario data. Alternatively or additionally, position controllers, especially fault diagnosis modules, can consider process scenario data in addition to approximate signals to determine whether the controller's approximation characteristics indicate normal or malfunctioning operation.

[0018] According to another improvement that can be combined with prior improvements, the position controller further establishes a procedure for performing at least one fault diagnosis routine while considering at least one control device signal from a list including control parameters, actual position signals, and guide signals, particularly process control signals. In particular, the control device signals can be selected from the list consisting of control parameters, actual position signals, and guide signals. For example, the fault diagnosis routine may include checks where control device signals available at least within the position controller are used to perform known control device fault diagnoses. Fault diagnosis routines are disclosed, for example, by DE102017124293A1, DE102010015647B4, DE102006003750B4, DE102005024674B4, DE102005024686B4, and DE19723650B9.

[0019] According to an alternative or additional design, the position regulator, and especially the reversing module, can be configured to determine an approximate signal corresponding to the process signal of the process regulator, such as the process differential signal and / or the actual process signal, which is not prepared for use by the valve control unit. The valve control unit can be configured to determine an approximate signal corresponding to the process signal of the process regulator, which is not directly transmitted from the process regulator to the valve control unit. In this way, the valve control unit can approximate the process signal of the upstream control loop. The approximate process signal can be used to perform fault diagnosis related to potential faults whose underlying causes are not within the cascade stage of the valve control unit, but rather within the cascade stage of the upstream process regulator of the valve control unit.

[0020] This document also relates to a valve regulating device for process equipment, comprising a regulating valve for regulating the flow of process fluid, an actuator for actuating the regulating valve, and a position regulator designed as described above for generating regulating parameters for the actuator. The actuator may be a pneumatic actuator, such as a pneumatic regulating drive, or an electric actuator, such as an electric drive.

[0021] This article also relates to process equipment, such as food processing equipment like breweries, power plant equipment like nuclear power plants, and chemical equipment like petrochemical equipment. Process equipment includes valve regulating devices for regulating the flow of process fluids. Process equipment may include multiple valve regulating devices for regulating the flow of one or more process fluids. One or more valve regulating devices of the process equipment can be designed as described above.

[0022] Furthermore, process equipment includes at least one process fluid user that receives or outputs a process fluid flow defined by valve regulation, particularly upstream, or by valve regulation, particularly downstream. Process fluid users may be, for example, reactors, heat exchangers, or cooling towers. Generally, a process fluid user refers to a component of the process equipment that generates, uses, or consumes process fluids.

[0023] Process equipment also includes process sensors that acquire process-specific signals relating to process fluid users and / or process fluids. Process-specific signals relating to process fluids can describe, for example, their temperature, pressure, volumetric flow rate, flow rate, etc. Process-specific signals relating to process fluid users can specifically describe measurements relating to process fluid users, such as mixing ratios, the content of multiple materials to be processed in the process, ambient temperature, pressure, pressure differentials or pressure gradients within the process fluid user, etc.

[0024] Furthermore, the process equipment includes a process controller, which provides a process control signal for valve control devices as a guide signal, based on theoretical and actual process signals. The process controller can be designed to compare the actual process signal with the theoretical process signal and provide a process control signal for the valve control devices from the comparison. For example, the process controller can calculate the process skew between the theoretical and actual process signals and determine the process control signal from the process skew using a process control routine and provide it to the valve control devices. The process controller can optionally be implemented in a PID controller architecture. In particular, the process equipment is designed such that the process controller directly provides the process control signal only to the valve control devices. In particular, the process equipment is designed such that the process controller neither directly transmits the theoretical process signal nor directly transmits the actual process signal and process skew to the valve control devices. This document also relates to a fault diagnosis method for valve control devices used in process equipment, which includes valve control devices and a process controller. During the use of the valve control devices within the equipment, the process controller provides process control signals to the valve control devices. The process control signal can be determined based on one or more process signals by the process controller. The valve regulating device can be designed, in particular, as described above. The process equipment can be designed, in particular, as described above.

[0025] In fault diagnosis methods, an approximate signal, particularly corresponding to the process signal, is determined from the process control signal and the controller model involving a specific controller, especially a process controller, and particularly the control reversal, via a valve control device. At least one fault diagnosis routine is executed by the valve control device, taking into account the approximate signal. In this way, the fault diagnosis method for the valve control device allows execution not simply limited to control parameters directly available within the control device. Fault diagnosis routines can be executed to ascertain the fault diagnosis result and generate a fault diagnosis code representing the result. It has been shown that it is advantageous for the fault diagnosis method to at least approximate the process signal, which, although existing in a higher-level controller, especially a higher-level process controller or a cascade of higher-level process controllers, cannot be directly provided to the valve control device from there. In this way, fault diagnosis routines implemented in the valve control device can identify the cause of a fault in the ball positioner or within the cascade stage.

[0026] This document may also relate to a method for operating a valve regulating device in a process apparatus having a process controller, wherein the process controller provides a process regulating signal to the valve regulating device. The process regulating signal may be processed by the valve regulating device in conjunction with a position actual signal to determine a regulating signal. Using the regulating signal, particularly an electrical or pneumatic signal, the actuator of the valve regulating device is controlled to actuate the regulating valve to regulate the flow of the process fluid. In this operating method, the regulating signal may be a pneumatic or electrical regulating signal, generated by the regulating electronics of the valve regulating device and provided to the actuator of the valve regulating device. The valve regulating device may consider the position differential between the process regulating signal and the position actual signal within the scope of the operating method in order to generate regulating parameters. The operating method may include the valve regulating device performing at least one fault diagnosis method as described above. This fault diagnosis method can take into account the process regulating signal, the position actual signal, and / or the regulating parameters.

[0027] According to an improved fault diagnosis method, the regulator model, particularly regulation reversal, i.e., the determination of the approximate signal and / or the fault diagnosis routine, is performed based on process scenario data characterizing the theoretical process signal. The process scenario data can particularly characterize a constant theoretical process signal. For example, regulation reversal can be performed first in the fault diagnosis method, involving a known regulator structure of the process regulator. The process scenario values ​​can define one or more boundary conditions that describe the mathematical composition or system of equations of the process regulator. The fault diagnosis routine can calculate the difference between the process approximate signal corresponding to the actual process signal and the particularly constant approximation of the theoretical process signal in the form of process scenario data to determine another approximate signal corresponding to the process skew. The fault diagnosis routine can compare the approximate signal corresponding to the process skew with an allowable numerical range and output a fault diagnosis result indicating an error in the process regulator characteristics when there is a deviation from the allowable numerical range.

[0028] In an improved fault diagnosis method, the time intervals involved in the process scenario data can be determined. Fault diagnosis routines may involve the execution of predetermined time intervals also involved in the process scenario data. For example, the process scenario data can be defined by involving one or more time-stable segments, within which the process scenario data represents a constant theoretical process signal, wherein different, especially consecutive, time intervals can correspond to different theoretical process signals.

[0029] According to an alternative implementation, the process scenario data may include a delay line and / or a signal shape definition for the theoretical process signal. In such a design of the fault diagnosis method, it may be advantageous to provide the theoretical process signal to the valve control device. The fault diagnosis method can be performed based on the process scenario data and at least one predetermined theoretical process signal, taking into account known delay lines and / or known signal shape definitions. By determining the time intervals involved in the process scenario data, the fault diagnosis method can be based on the time relationship between the process scenario data and valve control device parameters obtained in the valve control device, such as process control signals, actual position signals, position droops during control reversals, and / or fault diagnosis routines. Therefore, for example, the fault diagnosis method may include a delay line to account for the time misalignment between the process control device receiving the theoretical process signal and the process control device outputting the process control signal, particularly caused by the control cycle time, so that the fault diagnosis method, especially the control reversal and / or fault diagnosis routine analysis, analyzes signals that are typically closely related. The fault diagnosis method may, for example, consider the sinusoidal shape definition of the theoretical process signal as the process scenario data, from which it is known, for example, that the theoretical process signal has a ramp-like trend, a sinusoidal trend, or abrupt change. If the sinusoidal shape of the theoretical process signal is known at least approximately, this allows the valve regulator to perform more accurate fault diagnosis methods, even when the theoretical process signal cannot be characterized as a constant value.

[0030] According to one embodiment of the fault diagnosis method, process control signals are stored. In particular, the time curves of the process control signals are stored. It may be advantageous to store the process control signals or their time curves in the fault diagnosis method, especially at time intervals, for example as a series of discrete values, so that the fault diagnosis method can use the process control signals or their time curves as the basis for control reversal and / or fault diagnosis routines. With the help of the stored process control signals or the stored process control signal time curves, the characteristics of the superior process controller can be accurately described, especially in conjunction with process scenario data involving time intervals.

[0031] According to a preferred embodiment, the regulation reversal of the fault diagnosis method is determined based on a predetermined time-continuous, particularly real and / or parallel, regulator structure. The predetermined time-continuous regulator structure may correspond to a simulated process regulator regulation routine. According to an alternative design, the regulation reversal of the fault diagnosis method may be determined based on a predetermined time-discrete, particularly real and / or parallel, regulator structure. In particular, this regulation reversal may be performed based on a PID regulator structure. The predetermined time-discrete regulator structure may correspond to the digital regulation of a process regulator.

[0032] The reversal or inversion module can be configured to set up a transfer function G for reversal using a process PID controller. This transfer function G is calculated as the reciprocal of the variable z over the Z region by the following formula.

[0033] (1)

[0034] For the assumption that is available in many cases: τ = T C / 2, which simplifies the transfer function to:

[0035] (2) The parameters a0, a1, a2, and b0, b1, and b2, or a, b, and c, can be transmitted in a manner consistent with the process scenario data system characterizing the process regulator. These parameters can, in a suitable design, include constant predetermined parameters (a, b, and / or c) for calculating the reversible process regulation function. The stored parameters can be based on the signal a used to determine the approximate process signal. p The adjustment is reversed. It has been shown that the following simplified formula, assumed for c=0, provides sufficiently accurate results in simplified calculations:

[0036] (3) Parameters a, b, and / or c can be provided to the valve regulating device through manual user input.

[0037] It is conceivable that process scenario data can be determined at least partially automatically by the valve control device using initialization routines. Based on reference equipment or empirical values, the process scenario data can be stored in the memory of the valve control device, especially the position controller.

[0038] According to one implementation, the fault diagnosis method may include calculating an approximate actual process signal. The approximate actual process signal can be asymptotically calculated from the process control signal using, in particular, a linear function. For example, in a particularly simple approach, the actual process signal can be considered as a control parameter.

[0039] In a preferred embodiment of the fault diagnosis method, a comparison is performed between the fault diagnosis result and the predetermined theoretical characteristics of the regulating device. If a deviation between the fault diagnosis result and the predetermined theoretical characteristics is determined at this time, a fault diagnosis code can be generated. If no deviation between the fault diagnosis result and the predetermined theoretical characteristics is determined at this time, the fault diagnosis code can be disabled and / or deleted. Because the fault diagnosis method first performs a regulation reversal involving the upstream process controller of the valve regulating device to generate an approximate signal, the process approximate signal describing the characteristics of the upstream process controller of the valve regulating device can be taken into other fault diagnosis methods to check whether the current characteristics of the regulating device under the approximation characteristics of the process controller are consistent with the expected or at least permissible theoretical characteristics of the valve regulating device. If the valve regulating device indicates a prominent characteristic, but simultaneously eliminates the approximate signal determined by the fault diagnosis method, such that the prominent characteristic is consistent with the characteristic engraved by the process controller, the fault diagnosis code can be disabled and / or deleted; otherwise, the prominent characteristic of the valve regulating device will be generated and may be output. This avoids the output of false positive fault diagnosis codes. Alternatively or additionally, if the fault diagnosis results can identify inconsistencies with predetermined theoretical characteristics, a fault diagnosis code can be generated, indicating the prominent characteristics of the upstream process controller of the valve control device. A fault diagnosis code can be output, especially when a deviation is determined during comparison between the actual characteristics of the valve control device and known theoretical characteristics, even if the prominent characteristics of the valve control device are not indicated from the approximate characteristics of the process controller described by approximation signals.

[0040] This article also relates to the use of the valve regulating device, particularly as described above, for performing the fault diagnosis method, particularly as described above. The valve regulating device described above can be configured to perform the fault diagnosis method described above. Appendix picture illustrate

[0041] Other performance, advantages and features are described in the appendix below. picture The description of the preferred embodiments becomes clear, wherein:

[0042] Figure 1 A schematic diagram of a process equipment with a valve regulating device is shown. picture ;

[0043] Figure 2 A schematic box showing a digital position adjuster. picture ;

[0044] Figure 3 A schematic diagram illustrating the first operating method of a process equipment with a valve regulating device. picture ;and

[0045] Figure 4A schematic diagram illustrating a second operating method for a process equipment with a valve regulating device. picture . Detailed Implementation

[0046] In the following description of preferred embodiments, to facilitate readability, identical or similar components are accompanied by identical or similar attachments. picture mark.

[0047] This implementation may in particular demonstrate how a position regulator in a regulating device can obtain additional information for regulating device fault diagnosis through approximate reconstruction of the guide parameters or regulation parameters of a higher-level regulator, and how the approximate reconstruction can be mathematically understood one by one as the inversion of the transfer function of a sufficiently accurate model of the higher-level regulator.

[0048] Figure 1 A schematic diagram of the process equipment 100 is shown. picture It contains one or more cascaded control loops. For simplicity, based on... Figure 1 The illustration picture Only one control stage is shown. This control stage includes an upper-level process controller 120 and a lower-level valve control device 1. The upper-level process controller 120 may have exactly one field instrument, two or more field instruments, and especially control devices, which are not shown in detail here.

[0049] The upstream process controller 120 can be configured to guide the process 111. For this purpose, the process controller 120 can obtain a process actual signal p, for example, from the process sensor 105 of the process fluid used in 110. i Or multiple actual process signals. Regarding the desired process characteristics, a theoretical process signal p is set for the process controller 120. W Process theory signal p W The process controller 120 can be configured, for example, via a user interface such as the control computer 101 within the control console of the process equipment. The process controller 120 is configured to execute the theoretical process signal p. W With the actual signal p in the process i The comparison is used to determine the process skew p. e Based on process adjustment p e The process control routine is implemented by the process controller 120. As a result of the process control routine, the process controller 120 outputs a process control signal p. g The process control signal is supplied to the lower-level valve control device 1 so that the valve control device 1 acts on the process fluid in a desired manner, with the aim of making the actual process signal p i Convergence with process theory signal p W .

[0050] Valve regulating device 1 includes a position adjuster 31, an actuator 33, and a regulating valve 35. The regulating valve 35 acts on the process fluid supplied to the process fluid user 110. Alternatively, the regulating valve may also act on the outflow (not shown) of process fluid from the process fluid user 110. The regulating valve 35 can affect process fluid pressure, flow rate, etc. Clearly, the process fluid user 110 may include multiple process fluid inlets and / or multiple process fluid outlets, wherein the valve regulating device may correspond to one or more process fluid inlets and / or outlets associated with the process fluid user 110.

[0051] Valve regulating device 1 includes a position regulator 31 having an analog or digital position regulator electronics 400, as follows: Figure 2 The position regulator electronics 400, as detailed in the description, can be implemented at least partially by a computer-based adjustment module 401. The position regulator electronics 400 has a process control signal p. g The system includes a first signal input 420 and a second signal input 436 for the actual position value i. Based on the actual position value i and the process control signal p... g The adjustment routine is used to perform a comparison to calculate the position adjuster droop and determine the adjustment signal g. The position adjuster electronics 400 outputs the adjustment signal g at output 433 to actuate the actuator 33.

[0052] The position regulator electronics 400 also includes a reversal module 405, to which the process regulation signal p is generated. g As a signal input, process scenario data k describing the behavior of the superior process regulator 120 can be obtained from memory 404. Reversal module 405 is set up for obtaining process regulation signal p. g The process controller 120 is determined by reversing the regulation to approximate the signal a describing the upstream process controller 120. P Approximate signal a P This could correspond, for example, to the actual value of the process controller or the droop of the process controller. e The actual process signal is generally based on the time curve of the actual value of the process controller, such as a series of discrete actual values ​​of the process controller or the continuous time evolution of the actual value of the process controller. The following details the suitable design and function of the reversal module 405.

[0053] The valve regulating device 1 may also include a fault diagnosis module 407, such as a fault diagnosis electronic device, which can execute fault diagnosis routines associated with the valve regulating device 1. The fault diagnosis module 407 may be configured to execute known fault diagnosis routines for valve regulating devices. The fault diagnosis module 407 may be configured to generate at least one fault diagnosis code 408 based on at least one fault diagnosis routine. The fault diagnosis code may be displayed to the user on an optical display of the valve regulating device 1. The fault diagnosis code 408 may be processed on a process control console, process controller 120, or portable computer, such as a tablet PC. The fault diagnosis module 407 may be configured to be based on an approximate signal a. P At least one fault diagnosis routine is executed. The fault diagnosis module 407 can consider other signals available in the valve regulating device 1, and especially its position regulating electronics 31, under a fault diagnosis routine based on approximate signals. For example, the fault diagnosis module 407 can perform a fault diagnosis routine based on approximate signal a P When executing fault diagnosis routines, consider the process control signal p. g The following describes a possible design for a position regulator 400 with a configurable electronic computing and data storage device, including a computer-implemented fault diagnosis module 407, and parameters such as adjustment signal g, actual position signal i, and position regulator droop.

[0054] Figure 2 A block diagram of a digital position adjuster 31 configured with a configurable electronic computing and data storage device 400 is shown. picture Indicative box picture This describes a digital position regulator electronics device 400 with configurable electronic computing and data storage devices. However, the functions disclosed herein can be implemented, in part or entirely, using analog position regulator electronics components.

[0055] The digital position regulator electronics 400 includes, for example, a processor 403 in the form of a microprocessor, configured to perform various calculations. The processor 403 of the digital position regulator electronics 400 is logically associated with a memory 404. Various data and / or routines may be stored in the memory 404 for use by the processor 403. A first calculation module 401 for the adjustment routine of the valve regulating device 1 may be stored in the memory 404. The first calculation module 401 can be described as an adjustment module. Digital position adjustment can be implemented using the adjustment module. The adjustment module 401 can be implemented using the processor 403 to provide an adjustment signal g at the output 433 of the digital position regulator electronics 400 to actuate the actuator 35. The processor 403 can be configured with the help of the adjustment module 401 to perform calculations based on the actual position signal i provided by the position sensor 36 and the process adjustment signal p provided by the upstream process regulator 120. gThe calculation module 401 calculates the control routine. The control routine of the calculation module 401 can be, for example, a digital PID control routine.

[0056] The position regulator electronics 400 may have two or more signal inputs 420, 436 for signals to be processed in the processor 403 according to a routine. The digital position regulator electronics 400 includes a function for receiving process control signals p. g The first signal input 420 may include a digital-to-analog converter in an embodiment to generate a digital signal for use in the digital position regulator electronics 400, for example, based on a simple analog signal such as an analog 4.20mA process adjustment signal. The digital position regulator electronics 400 also includes a second signal input 436 for inputting the actual position signal i. The digital position regulator electronics 400 also includes an adjustment signal output 433. The processor 403 may be configured to design the adjustment module 401 with adjustment routines to adjust the signal i and p received at inputs 420 and 436. g Position adjustment is performed, and as a result, an adjustment signal g for actuating actuator 33 is provided at adjustment signal output 433. In an embodiment, adjustment signal output 433 may have a digital-to-analog converter or an electro-pneumatic converter to provide an adjustment signal g adapted to actuator 33. The digital position adjuster electronics 400 may have other signal inputs or signal outputs (not specifically shown). Additionally, the position adjuster may have an interface for manual data input.

[0057] Actuator 33 may be equipped with a signal amplifier to amplify the regulation signal g when using auxiliary electrical energy and / or auxiliary pneumatic energy from an auxiliary energy source.

[0058] The memory 404 of the digital position regulator electronics 400 can be occupied by one or more fault diagnosis routines to implement a fault diagnosis module 407. The fault diagnosis routines are configured for execution by the processor 403. The processor 403 can execute fault diagnosis routines, for example, those involving the adjustment signal g and the actual position signal. For example, the fault diagnosis routines can facilitate the execution of a partial stroke test and evaluate its results.

[0059] Memory 404 can be occupied by input data 402, wherein the input data 402 stored in memory 404 is appropriately associated with a certain time or time interval. In one embodiment, input data 402 is simply a regulating device signal. Processor 403 can be configured to execute a fault diagnosis routine using input data 402, which involves predetermined time intervals to compare current input data 402, for example, at the current time interval, with historical input data 402 at another time interval or a certain reference interval. Deviation from historical fault diagnosis results from the reference interval can, for example, indicate wear at regulating valve 35. The fault diagnosis routine can be designed to determine whether a prominent signal curve, such as operation, is present.

[0060] The valve regulating device 1 may include a position regulator 31 as shown above, which is configured to execute fault diagnosis routines. This is achieved by equipping the position regulator 31 with digital position regulator electronics 400, which includes a memory 404 along with fault diagnosis routines 407 stored thereon and a processor 403 for executing the fault diagnosis routines 407. The position regulator 31 may generate regulation parameters g for the actuator 33 using the digital position regulator electronics 400.

[0061] Within the scope of this document, the position regulator is also configured to perform regulation reversal, which involves the upstream process regulator 120. Regulation reversal can be initiated from the process regulation signal p. g Determine the approximate signal a P Fault diagnosis routine 407 can be based on approximate signal a. P Therefore, the memory 404 of the configurable electronic computing and data storage device 400 may be equipped with a second computing module 405, which may be referred to as a modulation module or an inversion module.

[0062] The second calculation module includes configuration data 406 for determining a regulator model for a given regulator. The configuration data 406 for adjusting the model is used to adapt the regulator model to a specific regulator, such as a process regulator upstream of a valve control device. Process scenario data 409, characterizing the features of the process regulator 120 upstream of the valve control device 1, may optionally be stored in memory 404. The processor 403 may be configured to execute the second calculation module 405 and / or at least one fault diagnosis routine 407, incorporating the process scenario data 409. A diagram illustrating position adjustment performed in the position regulator 31, and concurrent adjustment reversals and, possibly, fault diagnoses. picture exist Figure 3 The first embodiment and in Figure 4 The embodiments shown are illustrated in the examples.

[0063] Reference Figure 1And it is clear that, within the process regulation range executed by process controller 120, the known process variables are the actual process signal p. i and process theory signal p W Based on this premise, the process control signal p is determined by using a predetermined process control routine as an unknown process variable to be calculated. g The process control routine can be represented by a model controller. The process control signal p g The signal p is transmitted to the lower-level position regulator 1. W Actual process signal p i Other process signals are generally unknown to valve position regulator 1.

[0064] Figure 3 The design of the operating method is illustrated, in which adjustment is performed and, in parallel with it, a fault diagnosis method including adjustment reversal and, possibly, fault diagnosis routines. The second calculation module 405 may include configuration data 406 for adjusting the model. The second calculation module or reversal module 405 may in particular establish a process adjustment routine for depicting the reversal of the model regulator, thereby approximating the process adjustment routine of the upstream process regulator 120 of the valve regulating device 1. The second calculation module 405 establishes a transfer function relating to the upstream process regulator 120 in a spectral range such as Laplace space or Z space. The implementation of the adjustment reversal performed by the second calculation module 40 in the processor 403 of the digital position regulator electronics 400 is based on the process adjustment parameter p received by the regulated device 1 from the output of the process regulator 120. g Input data (p) to the gradual reconstruction process regulator 120 i ,p W The second calculation module 405 is designed to adjust the process signal p, which is a known variable, via the processor 403. g The calculation is performed with the aid of process scenario data k, to calculate an approximate signal a, which is considered an unknown variable. P Approximate signal a P Corresponding to process signals, especially process droning p e Or the actual signal p in the process i .

[0065] The process scenario data k or 409 can be correlated with the theoretical process signal. Based on the process scenario data k, the theoretical process signal p, which is at least sometimes constant, can be assumed in the regulation simulation using the second calculation module 405, especially in regulation reversal. w Regulation and reversal can be achieved using process scenario data k based on multiple different, especially constant, process theory signals p. W Each of these is associated with a different time interval. Alternatively or additionally, the second calculation module 405 may use process scenario data k, which depicts the non-constant process theoretical signal p.W The time curve. According to another alternative option, the process scenario data k can provide the second calculation module 405 with information about the process theoretical signal p. W Information about the signal curve characteristics. For example, process scenario data k can provide the second calculation module 405 with information about, for example, the theoretical process signal p. w The information is a linear, sloping curve. The process scenario data k can provide the second calculation module with information about the sinusoidal curve of the process theory signal, such as its frequency, amplitude, amplitude direction offset, or time dimension offset. Alternatively or additionally, the second calculation module can consider the process scenario data, which describes the abrupt change characteristics of the process theory signal, such as its amplitude, frequency, and abrupt change time.

[0066] like Figure 3 The operating method shown involves a position regulator 31, which, from its superior process regulator 120, only processes the process regulation signal p. g Position adjuster 31 according to Figure 3 The embodiments shown, in addition to the process control signal p g It does not process other signals directly obtained from the cascaded upper-level controllers. In particular, the position controller 31, in addition to the process control signal p, does not process other signals. g The external process controller cascaded from the higher level does not receive other signals. Figure 3 In the method shown, the position regulator is provided with predetermined process scenario data k(t), particularly relating to the time interval t2-t1. For example, the process scenario data k can be manually input as an empirical value through a user interface. Alternatively or additionally, the process scenario data k can be stored in the memory 404 of the position regulator electronics 400 under factory-set conditions, after which the valve regulating device 1 is initially put into use.

[0067] Figure 4 An alternative design for the operating method is shown, in which regulation is performed and, in parallel with it, a fault diagnosis method including regulation reversal and, perhaps, fault diagnosis routines. Figure 4 The schematic diagram illustrates the operating method and its basis. Figure 3 The main difference between the methods lies only in providing or obtaining process scenario data k. Valve regulating device 3, according to... Figure 4 In one embodiment, there is another input to receive at least one process theory signal p from the process equipment 100. W Process theory signal p W It can be received, for example, as a series of digital process theory signals. For example, the analog or digital signal input of valve regulating device 1 can be received as another input value to receive the process theory signal p. WIt appears to be supplied in the process equipment 100 to the process controller 120 for process regulation. Alternatively, it can be conceivable that the process controller 120 is configured and adapted for signal transmission to the valve control device 1, and will also transmit the theoretical process signal p. w The other input is transmitted to valve regulating device 1. The theoretical process signal p g The theoretical signal p of the process to be processed can be represented, for example, in digital form as a series of sequential signals by the valve regulating device 1. W The timing q of the process theory signal is received and stored in memory 404 as process scenario data k(q) by the digital position regulator electronics 31. According to an advantageous embodiment, the timing q of the process scenario data is assigned to the received process theory data for a certain time or time interval t. The received process theory signal p is the timing q. W It can be stored as process scenario data 409 in association with a delay line or time offset. With the aid of the time offset or delay line 411, a process theoretical signal p, logically correlated with the second calculation module 405, can be shifted forward in a particularly reversible adjustment routine that can be adjusted using configuration data 406. W Adjustment signal p during time shift process g The correlation. For example, regulation reversal can be based on the process regulation signal p. g Combined with the process theory signal p of the periodic time displacement of the digital position regulator electronic device 400 W .

[0068] In digital process control or digital control device control, there is generally a time delay, particularly exactly one process controller cycle, between the reception of the theoretical process value and the output of the process control signal associated with the theoretical process value using the process control routine. For control reversal to determine the actual process value or a precise approximation of the process control value based on the controlled process value, it may be helpful to consider both the controlled process value and the original theoretical process value, particularly within exactly one process controller cycle, during control reversal. Alternatively, a sufficiently accurate approximation can be performed without delay, especially in slow processes with slow, particularly continuously variable, theoretical process signals.

[0069] The second calculation module 405 preferably describes the reciprocal of the process controller 120, which is configured as a model controller according to the PID controller structure. For example, the second calculation module 405 can implement regulation reversal, particularly with respect to the process controller 120 simulated as a PID controller. In particular, the reversal module 405 can perform regulation reversal for the process controller 120 simulated as a P controller, I controller, PD controller, PI controller, or PID controller. The process controller 120 simulated in the PID controller structure can be described by the mathematical function G.PID To describe it, it starts from known variables, i.e., the process theory signal p. W Actual process signal p i and / or process adjustment deviation p e As an unknown variable and output value, the process control signal p is determined. g In the model module or reversal module 405, the known mathematical regulation function can be calculated in such a reversible manner that the process regulation signal p g The process theory signal p, which is a known variable and a variable considered to be at least approximately known. W Take them together to determine, in particular, the actual value p corresponding to the process. i Or process adjustment deviation p e Approximate signal a P In, for example, in Figure 0 The process control routine of process controller 120 in the PID controller structure sketched in the paper can be mathematically represented in Laplace space L using the following formula:

[0070] (4)

[0071] (5) x(t)=L -1 {X(s)}

[0072] in,

[0073] W(s) depicts the theoretical value p of the process. W Truth function of time curve Laplace transform;

[0074] X represents the discrete or time-continuous process signal p. i The actual value of the process;

[0075] Y V p represents a discrete or time-continuous process control signal. g Process adjustment values; and

[0076] G PID Describe the transfer function of a PID process controller, and

[0077] s represents the relationship with the variable Laplace.

[0078] For a time-continuous PID controller with a parallel architecture, its transfer function has a true D-part time constant τ in the Laplace region, including the proportional gain K. P Reset time (Nachstellzeit) T N and retention time (Vorhaltzeit) T V The following conditions apply:

[0079] (6)

[0080] For valve position regulators, it may be advantageous that equation (5) is implemented as a difference equation and used in the following equation (6) and considered with respect to the discrete sampling step k:

[0081] (7)

[0082] For a time-discrete regulator, the transfer function can be determined using the Tustin transform according to equation (7), where T C Select based on the cycle time of the process controller:

[0083] (8)

[0084] Therefore, we can conclude that:

[0085] (9)

[0086] in,

[0087] (10)a2=2T N (T C +2τ)

[0088] (11)a1=-8τT N

[0089] (12)a0=-2T N (T C -2τ)

[0090] (13)b2=2T N (T C +2τ)+T C (T C +2τ)+4T N T V

[0091] (14)

[0092] (15)b0=-2T N (T C -2τ)+T C (T C -2τ)+4T N T V

[0093] When using the position regulator electronics 400, the process control signal p can be obtained from the analog module or the reversal module 405. g Approximate calculation of an approximate signal a PIts relationship with process adjustment p e Or the actual signal p in the process i Related.

[0094] Alternatively, different calculations can be performed directly at time intervals for many regulator structures without using Laplace space. For example, an approximate signal corresponding to the signal response of a PI regulator can be determined. The time-dependent transfer function G of the PI process regulator... PI The reversal of (t) is known. The regulator model can be defined with respect to the transfer function G with proportional back-calculation coefficients. PI The P coefficient of (t) and the I coefficient with respect to the differential along with the proportional differential coefficient are configured (not shown in detail). A time-continuous PI regulator G is used. PI The inverted transfer function of (t) can be used to determine the approximate signal a from the pilot signal provided by the process controller. P .

[0095] Fault diagnosis routine 409 can be set up to analyze and describe an approximate signal a for one or more process adjustments. P For example, a set of approximate adjustment p determined by a time sequence q. e Fault diagnosis routine 407 can be used to determine fault diagnosis codes 408 related to the stability, accuracy, overshoot, and stability of the upstream process control. For example, the stability of the overall control loop, which includes process and position control, can be evaluated.

[0096] For example, the amount of overshoot can be considered for fault diagnosis. Based on the amount and magnitude of overshoot in fault diagnosis routine 407, a fault diagnosis code 408 related to the quality of process guidance and position adjustment can be determined. For example, if a slight overshoot exists, fault diagnosis routine 407 can be used as a fault diagnosis result to determine that efficient process guidance and position adjustment exist. Starting from an overshoot amount higher than a threshold, fault diagnosis routine 407 can be used to determine that adjusting the adjustment parameters of position regulator 1 and / or process regulator 120 is beneficial to improving process guidance and position adjustment.

[0097] The above explanation picture and The features disclosed in the claims may be meaningful not only individually but also in any combination for implementing the invention in different designs.

[0098] Appendix picture Tag list

[0099] 1. Adjustment device

[0100] 31 Position Adjuster

[0101] 33 Actuator

[0102] 35 Control valve

[0103] 100 Process Equipment

[0104] 105 Process Sensors

[0105] 10 Process Fluid Users

[0106] 111 Equipment Process

[0107] 120 process controller

[0108] 400 Position Adjuster Electronic Device

[0109] 401 Adjustment Module

[0110] 402 Input Data

[0111] 403 processor

[0112] 404 memory

[0113] 405 Calculation Module

[0114] 406 Configuration Data

[0115] 407 Fault Diagnosis Module

[0116] 408 diagnostic code

[0117] 409 Process Scenario Data

[0118] 411 Delay Line

[0119] 420 First signal input

[0120] 433 output

[0121] 436 Second signal input

[0122] a P Approximate signal

[0123] g Adjustment signal

[0124] i Adjust the actual value

[0125] k process scenario data

[0126] p d Process adjustment

[0127] p e Process adjustment

[0128] p g Process Theory Signal

[0129] p i Actual process signal

[0130] p W Process Theory Signal

[0131] q timing

Claims

1. A position regulator (31) for a valve regulator device (1) of a process plant (100), the position regulator (31) comprising: a first signal input (11) for a guiding signal, a second signal input for a position actual signal (i) associated with a regulating valve (35), wherein the position regulator (31) is set up to generate a regulation parameter (g) for actuating an actuator (33) of the regulating valve on the basis of the guide signal and the position actual signal (i) and comprises a control output for the regulation parameter (g), characterized in that the position regulator (31) is set up to calculate an approximation signal (a p ) from the guide signal and a regulation inversion relating to the process regulator (120) by means of a regulation model relating to the specific regulator, which can be configured, wherein the regulation model is configured such that a signal generated by the specific regulator from the approximation signal (a p ) corresponds to the guide signal.

2. The position adjuster (31) according to claim 1, the position adjuster (31) being set up for performing at least one fault diagnosis routine taking into account the approximation signal (a p ).

3. The position adjuster (31) according to claim 2, further comprising a memory (9) occupied by the process scene data (k), and wherein, The position regulator (31) is set up for determining the approximation signal (a p ) in consideration of the process scenario data (k) and / or for executing the at least one fault diagnosis routine in consideration of the process scenario data (k).

4. The position adjuster (31) according to claim 2, wherein The position regulator (31) is further set up for executing the at least one fault diagnosis routine in consideration of at least one regulating device signal from a list comprising a regulating parameter (g), a position actual signal (i) and a process regulating signal (p g ).

5. The position adjuster (31) according to claim 1, wherein The position regulator (31) is set up to determine an approximation signal (a p ) which corresponds to a process setpoint signal (p e ) not prepared for the valve regulator (1) and / or a process actual signal (p i ) of the process regulator (120).

6. The position adjuster (31) according to claim 1, wherein The guiding signal is a process regulating signal (p g ) of a process regulator (120) of the process plant (100).

7. The position adjuster (31) according to claim 1, wherein the position regulator (31) being set up to generate a pneumatic regulating parameter (g) for actuating an actuator (33) of the regulating valve based on the guiding signal and the position actual signal (i) and comprising a pneumatic control output for the regulating parameter (g).

8. The position adjuster (31) according to claim 1, wherein, The position regulator (31) is set up to calculate an approximation signal (a p ) from the guide signal by means of a configurable regulator model which relates to the process regulator (120).

9. A valve regulator device (1) for a process plant (100), the valve regulator device (1) comprising a regulating valve (35) for regulating a process fluid flow, an actuator (33) for actuating the regulating valve (35) and a position regulator (31) according to any one of claims 1 to 8.

10. Valve regulating device (1) according to claim 9, wherein the valve regulator device (1) comprising a pneumatic or electric actuator (33) for actuating the regulating valve (35).

11. A fault diagnosis method for a valve regulating device (1) according to claim 9 in a process plant (100) having a process regulator (120) controlling the valve regulating device (1), wherein from the process regulator (120) to the valve regulating device (1) a process regulating signal (p g ), and wherein a regulator model relating to a specific regulator is configured, and an approximation signal (a p ) is determined from the process regulating signal (p g ) and the regulator model relating to the regulator by the valve regulating device (1), and wherein at least one fault diagnosis routine is performed by the valve regulating device (1) with consideration of the approximation signal (a p ).

12. The failure diagnosis method according to claim 11, wherein The approximate signal (a p ) is determined and / or the fault diagnosis routine is further performed based on process scenario data (k) characterizing a process theory signal (p w ).

13. The failure diagnosis method according to claim 12, wherein The time interval involved by the process scenario data (k) is determined, and / or wherein the process scenario data (k) contains a delay line and / or a signal shape definition of the process theory signal (p w ).

14. The failure diagnosis method according to any one of claims 11 to 13, wherein The process regulation signal (p g ) is stored.

15. The failure diagnosis method according to claim 11, wherein the regulator model being determined based on a predetermined time-continuous or time-discrete regulator structure.

16. The failure diagnostic method according to claim 15, wherein The modulation pass through is reversed by a pass through within the Z region on variable z Formation.

17. The failure diagnosis method according to claim 12, wherein performing a comparison of the fault diagnosis result with a predetermined theoretical characteristic of the valve regulator device (1).

18. The failure diagnosis method according to claim 17, wherein generating a fault diagnosis code if a deviation between the fault diagnosis result and the predetermined theoretical characteristic is determined when performing the comparison, and / or wherein a fault diagnosis code is inhibited and / or deleted if no deviation between the fault diagnosis result and the predetermined theoretical characteristic is determined when performing the comparison.

19. The failure diagnosis method according to claim 11, wherein a regulator model relating to the process regulator (120) is configured.

20. The failure diagnosis method according to claim 12, wherein The approximate signal (a p ) is determined and / or the fault diagnosis routine is further performed on the basis of process scenario data (k) which characterizes a constant process theory signal.

21. The failure diagnostic method according to claim 15, wherein The process regulation signal (p g ) time curve is stored.

22. The failure diagnostic method according to claim 15, wherein the regulating reversal is determined based on a predetermined time-continuous or time-discrete regulator structure. the regulating reversal is determined based on a predetermined time-continuous or time-discrete regulator structure.

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