Three-valve split-range control manual and automatic undisturbed switching method

Abstract

The invention relates to the technical field of control and switching of regulating valves, and discloses a three-valve split-range control manual-automatic undisturbed switching method, which is applied to a three-valve control loop, comprises a PID (Proportion Integration Differentiation) controller and a three-valve execution module, and comprises the following steps: in a closed-loop automatic mode, based on a split-range control rule, simultaneously controlling the opening degrees of three valves by using an output value of the PID controller; when the three-valve control loop is switched from an open-loop manual mode to a closed-loop automatic mode, a comprehensive valve position value is calculated by using a preset inverse operation rule based on an opening instruction of a three-valve execution module, and the inverse operation rule is obtained by reversely solving a split-ranging control rule; and synchronizing the output value of the PID controller into the comprehensive valve position value, and switching to a closed-loop automatic mode after a preset time period. According to the method, undisturbed switching between the manual mode and the automatic mode of the three-valve system is achieved, intelligent synchronization of PID controller output is achieved, switching disturbance is eliminated, the stability and safety of the control system are improved, and operation flexibility is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control and switching of regulating valves, and particularly to a three-valve split-range control hand-automatic non-disturbance switching. BACKGROUND

[0002] In industrial process control, it is often necessary to drive a regulating valve through a control system to stabilize a process parameter at a set value. However, a single regulating valve is subject to its inherent flow characteristics, and in a working condition requiring high control precision and wide regulating range, it is difficult to simultaneously meet the requirements of precise control at small flow and rapid regulation at large flow. To address this challenge, the industry usually adopts a scheme of a large valve and a small valve constituting a split-range control system, wherein the small valve is responsible for fine adjustment in small flow working conditions, and the large valve undertakes the adjustment task in large flow working conditions. In addition, to achieve rapid response to reverse changes in the set value, a reverse-acting valve, such as a water supply valve, needs to be introduced into the system, thereby forming a complex control architecture in which three valves are connected in parallel and respond to the output of a same PID controller (Proportion Integration Differentiation).

[0003] At present, the existing technology mainly focuses on the design and switching of a double-valve control system, and no effective solution has been proposed for the non-disturbance switching between hand-automatic control modes of a complex system containing three regulating valves. Specifically, the existing technology cannot solve the core problem of intelligently and non-disturbance calculating and synchronizing the PID output value according to the arbitrary manual operation state of the three valves when switching from the manual mode back to the automatic mode in three-valve split-range control, which further limits the application of the control strategy in higher precision and wider range industrial scenarios. SUMMARY

[0004] Therefore, the present application provides a three-valve split-range control hand-automatic non-disturbance switching method, which mainly aims to solve the technical problem that in the prior art, it is impossible to intelligently and non-disturbance switch from the manual mode back to the automatic mode according to the manual operation state of the three valves in three-valve split-range control.

[0005] According to the present application, a three-valve split-range control hand-automatic non-disturbance switching method is provided, which is applied to a three-valve control loop, the three-valve control loop comprising a PID controller and a three-valve execution module, the three-valve execution module comprising a water supply valve, a first discharge valve and a second discharge valve, and the method comprising: When the three-valve control loop is in a closed-loop automatic mode, the split-range control rule set between the output value of the PID controller and the opening instruction of the three-valve execution module is used to control the opening of the water supply valve, the first discharge valve and the second discharge valve simultaneously by using the output value of the PID controller. When the three-valve control circuit is switched from the open-loop manual mode to the closed-loop automatic mode, a comprehensive valve position value is calculated based on the opening instruction of the three-valve execution module currently set manually by using a preset inverse operation rule, wherein the inverse operation rule is obtained by inversely solving the split-range control rule; The output value of the PID controller is synchronized to the comprehensive valve position value, and the three-valve control circuit is switched to the closed-loop automatic mode after a preset time period.

[0006] Optionally, the output range of the output value of the PID controller is -100% to 100%; and the split-range control rule is that when the output value of the PID controller is -100% to 0%, the makeup water valve is in an open state, and the first discharge valve and the second discharge valve are both in a fully closed state; when the output value of the PID controller is 0% to a first split-range point, the makeup water valve and the first discharge valve are both in a closed state, and the second discharge valve is in an open state; when the output value of the PID controller is the first split-range point to a second split-range point, the makeup water valve is in a closed state, and the first discharge valve and the second discharge valve are both in an open state; when the output value of the PID controller is the second split-range point to 100%, the makeup water valve is in a closed state, the first discharge valve is in an open state, and the second discharge valve is in a fully open state; wherein 0% < the first split-range point < the second split-range point < 100%.

[0007] Optionally, the calculation of the comprehensive valve position value by using the preset inverse operation rule comprises: when the opening instruction of the makeup water valve set manually is greater than 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening instruction of the makeup water valve; when the opening instruction of the makeup water valve set manually is equal to 0% and the opening instruction of the first discharge valve is greater than 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening instruction of the first discharge valve; and when the opening instruction of the makeup water valve set manually is equal to 0% and the opening instruction of the first discharge valve is equal to 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening instruction of the second discharge valve.

[0008] Optionally, before the step of synchronizing the output value of the PID controller as the integrated valve position value, the method comprises: determining whether the valve opening degree of the three-valve execution module is in a switching ready state, wherein the switching ready state comprises: when the opening degree instruction of the makeup valve is greater than 0%, setting the opening degree instruction of the first discharge valve and the opening degree instruction of the second discharge valve to 0%; or, when 0% < the opening degree instruction of the second discharge valve ≤ the opening degree instruction of the second discharge valve corresponding to the first split point, setting the opening degree instruction of the makeup valve and the opening degree instruction of the first discharge valve to 0%; or, when the opening degree instruction of the second discharge valve corresponding to the first split point < the opening degree instruction of the second discharge valve ≤ 100%, setting the opening degree instruction of the first discharge valve to the first target opening degree instruction corresponding to the opening degree instruction of the second discharge valve in the closed-loop automatic mode, and setting the opening degree instruction of the makeup valve to 0%; or, when 0% < the opening degree instruction of the first discharge valve ≤ the opening degree instruction of the second discharge valve corresponding to the second split point, setting the opening degree instruction of the second discharge valve to the second target opening degree instruction corresponding to the opening degree instruction of the first discharge valve in the closed-loop automatic mode, and setting the opening degree instruction of the makeup valve to 0%; or, when the opening degree instruction of the second discharge valve corresponding to the second split point < the opening degree instruction of the first discharge valve ≤ 100%, setting the opening degree instruction of the second discharge valve to 100%, and setting the opening degree instruction of the makeup valve to 0%.

[0009] Optionally, the method further comprises: when it is determined that the valve opening degree of the three-valve execution module is not in the switching ready state, stopping switching the three-valve control loop from the open-loop manual mode to the closed-loop automatic mode based on a preset prohibition rule.

[0010] Optionally, the preset prohibition rule comprises a makeup valve prohibition closed-loop rule, a first discharge valve prohibition closed-loop rule, and a second discharge valve prohibition closed-loop rule.

[0011] Optionally, the makeup valve prohibition closed-loop rule comprises: the opening degree instruction of the makeup valve is greater than 0%, and the opening degree instruction of the first discharge valve is greater than 0% or the opening degree instruction of the second discharge valve is greater than 0%.

[0012] Optionally, the first discharge valve prohibition closed-loop rule comprises: the opening degree instruction of the first discharge valve corresponding to the second split point > the opening degree instruction of the first discharge valve > 0%, and the opening degree instruction of the second discharge valve is not equal to the first target opening degree instruction, or the opening degree instruction of the makeup valve is greater than 0%; or, the opening degree instruction of the first discharge valve > the opening degree instruction of the first discharge valve corresponding to the second split point, and the opening degree instruction of the second discharge valve < 100% or the opening degree instruction of the makeup valve > 0%.

[0013] Optionally, the second discharge valve prohibits the input of the closed loop rule includes: the first split point corresponding to the second discharge valve opening degree instruction > the second discharge valve opening degree instruction > 0%, and the first discharge valve opening degree instruction > 0% or the first water valve opening degree instruction > 0%; or, the second discharge valve opening degree instruction > the first split point corresponding to the second discharge valve opening degree instruction, and the first discharge valve opening degree instruction is not equal to the second target opening degree instruction, or the water valve opening degree instruction is greater than 0%.

[0014] Optionally, the water valve, the first discharge valve and the second discharge valve are respectively provided with a hand controller module; the method further comprises: when the three valve control circuit is switched from the closed loop automatic mode to the open loop manual mode, the hand controller module locks and keeps the current output value of the PID controller as the manual output value, thereby maintaining the opening degree instructions of the water valve, the first discharge valve and the second discharge valve unchanged.

[0015] The three-valve split control hand-automatic seamless switching method provided by the application, in the closed loop automatic mode, the opening degrees of the three valves are uniformly controlled by the output value of the PID controller according to the preset split control rule, a complete forward control logic is established, and a basic mapping relationship for subsequent realization of hand-automatic seamless switching is provided; a comprehensive valve position value is introduced, a comprehensive valve position value is calculated based on the current manual opening degree instructions of the three valves by using a preset inverse operation rule, and the inverse operation rule is established based on inverse solving of the split control rule, so that a single variable of the PID output value is inversely deduced from the multivariable of the three-valve opening degree instructions, intelligent pre-synchronization of the PID controller output value is realized, and the technical problem that the prior art cannot intelligently calculate the PID controller output value according to the manual state is solved; finally, the output value of the PID controller is synchronized to the calculated comprehensive valve position value, and mode switching is completed after a preset time period, so that the continuity of the control output in the switching moment is ensured, process disturbance caused by output jump is effectively avoided, and the stability and reliability of the switching process are improved. The above method realizes seamless switching between the hand-automatic modes of the three-valve system by constructing a split control forward logic, inversely operating to solve a comprehensive valve position, synchronizing a PID output, and delaying switching, realizes intelligent synchronization of the PID controller output, eliminates switching disturbance, improves the stability and safety of the control system, and enhances the operation flexibility.

[0016] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, the specific embodiments of the application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate exemplary embodiments of the application and together with the description serve to explain the application. In the drawings: Figure 1 A flowchart of a three-valve split-range control hand-automatic seamless switching method provided by an embodiment of the application is shown. DETAILED DESCRIPTION

[0018] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood, and the scope of the present application can be accurately conveyed to those skilled in the art.

[0019] An embodiment of the present application provides a three-valve split-range control hand-automatic seamless switching method, as shown in the figure, which includes the following steps: Figure 1 101. When the three-valve control loop is in closed-loop automatic mode, the opening degrees of the water supply valve, the first drain valve, and the second drain valve are simultaneously controlled by using the output value of the PID controller based on the split-range control rule set between the output value of the PID controller and the opening degree instruction of the three-valve execution module.

[0020] The method provided by the present application is applicable to a three-valve control loop, the core function of which is to accurately and widely automatically adjust a certain key process parameter through the coordinated action of three regulating valves. The entire loop includes two main parts, one of which is the control core, i.e., the PID controller, and the other of which is the execution mechanism, i.e., the three-valve execution module. The PID controller is the brain of the entire control loop, which is responsible for real-time calculation and output of a control signal (usually a standard signal of -100% to 100%) for driving the execution mechanism to act in order to eliminate the deviation and stabilize the process based on the deviation between the measured value and the set value of the process parameter. The three-valve execution module is the execution unit of the control instruction, which is composed of three regulating valves, specifically including a water supply valve for supplying medium into the system, which is usually opened when the process parameter is low to play a positive regulating role, for example, in a liquid level control system, when the liquid level is too low, the water supply valve is opened to raise the liquid level; a first drain valve, i.e., a large drain valve, which has a large flow capacity and is suitable for rapid regulation under large flow conditions, and when the system needs to drain a large amount of medium, the first drain valve is opened to achieve rapid response; and a second drain valve, i.e., a small drain valve, which has a small flow capacity and is more suitable for fine regulation under small flow or stable conditions close to the set value, so that the valve is fine-tuned to improve control accuracy and stability.​

[0021] Specifically, when the three-valve control loop is in the closed-loop automatic mode, the system adopts a split-range control strategy, mapping the output value of the PID controller to the opening degree instructions of the three valves according to a preset split-range rule; specifically, the negative value range of the PID controller output is used to control the opening degree of the water replenishing valve to realize the liquid replenishing operation when the liquid level is low; and the positive value range is allocated to the two discharge valves, wherein the smaller positive value range controls the second discharge valve for fine adjustment in a small flow condition, and the larger positive value range controls the first discharge valve for rapid response in a large flow condition, and the control ranges of the two discharge valves partially overlap to realize smooth transition of flow adjustment. Through the preset split-range control rule, the single output signal of the PID controller can coordinate to drive the three valves, automatically select the appropriate valve combination for adjustment according to the process requirements, so as to balance the control accuracy and response speed.

[0022] In the embodiments of the present application, the split-range control rule is used to realize the cooperative work of the three valves, effectively expanding the adjustment range of the system, and solving the technical problem that a single valve cannot balance the small flow accurate control and the large flow rapid adjustment; using a unified PID controller output to drive multiple valves simplifies the control structure, avoids the coordination problem between multiple controllers, and improves the reliability and maintainability of the system; by reasonably setting the split-range points and the overlapping range, the leading valve can be automatically switched under different working conditions, the smooth transition of the control process is realized, and the fluctuation of the process parameters is reduced; this step lays a foundation for subsequent realization of manual-automatic non-disturbance switching, establishes a clear positive mapping relationship between the PID output and the valve opening degree in the automatic mode, so that the PID output value can be inversely calculated in the manual mode, thereby ensuring the stability of the switching process.

[0023] 102、When the three-valve control loop is switched from the open-loop manual mode to the closed-loop automatic mode, based on the opening degree instructions of the three-valve execution module currently set manually, a comprehensive valve position value is calculated by using a preset inverse operation rule, wherein the inverse operation rule is obtained by inversely solving the split-range control rule.

[0024] The open-loop manual mode refers to that the control system is separated from the automatic adjustment state, and the operator directly sets the opening degree of each valve; the closed-loop automatic mode refers to that the system automatically calculates the output and adjusts the valve opening degree according to the deviation between the real-time measurement value and the set value of the process parameter, to form a feedback control loop; the opening degree instruction is a signal output by the control system to the valve actuator, indicating the expected opening degree of the valve, usually in percentage form; the inverse operation rule refers to the mathematical or logical mapping relationship derived from the PID output value according to the forward split-range control logic of the control valve in the closed-loop automatic mode; the comprehensive valve position value refers to an equivalent PID output value calculated by the inverse operation rule according to the actual opening degree instructions of the current three valves in the open-loop manual mode, which is used as the initial output reference when switching back to the automatic mode.

[0025] Specifically, when the three-valve control loop needs to switch back to the closed-loop automatic mode from the open-loop manual mode, in order to avoid control disturbance caused by the inconsistency between the PID output value and the actual valve opening degree, the system introduces a comprehensive valve position value calculation mechanism, specifically, the system first reads the opening degree instructions of the water supply valve, the first discharge valve and the second discharge valve set manually; then, according to the pre-set inverse operation rule, the three opening degree values are logically judged and inversely solved, the inverse operation rule is reversely constructed based on the split-range control rule in the automatic mode, for example, when the opening degree instruction of the water supply valve is greater than 0%, the corresponding PID output value is inversely deduced according to the split-range mapping relationship of the water supply valve; when the water supply valve is closed and the first discharge valve is opened, the PID value is inversely deduced according to the split-range interval of the first discharge valve; when only the second discharge valve is opened, the PID value is inversely deduced according to the control interval of the second discharge valve, through the setting of the priority logic, the system finally determines a unique comprehensive valve position value as the target output value of the PID controller before switching.

[0026] In the embodiments of the present application, the control disturbance problem caused by output mismatch during the manual-to-automatic switching process of the multi-valve system is effectively solved, which has significant beneficial effects. First, by introducing the inverse operation rule and the comprehensive valve position value, an intelligent mapping from the multi-variable manual operation state to the single-variable PID output is realized, ensuring the consistency of the PID output and the current valve state before switching, fundamentally eliminating the output jump at the switching moment, and realizing truly disturbance-free switching. Second, this step improves the operation flexibility and safety of the system, allowing the operator to freely adjust the opening degree of any valve in manual mode, and the system can still accurately calculate the reasonable synchronization value without strictly following a specific operation sequence, reducing the risk of human error. Finally, this step enhances the intelligent level of the control system, providing reliable technical support for the automatic commissioning of complex multi-actuator systems, and is particularly suitable for industrial process control scenarios with extremely high stability requirements.

[0027] 103. synchronizing the output value of the PID controller to the integrated valve position value, and switching the three-valve control loop to the closed-loop automatic mode after a preset time period.

[0028] Specifically, when the system is ready to switch back to the closed-loop automatic mode from the open-loop manual mode, in order to ensure a smooth and disturbance-free switching process, a step-by-step control strategy of synchronization followed by switching is adopted. The specific implementation process is as follows: after calculating the integrated valve position value, the current output value of the PID controller is forcibly set to the integrated valve position value, ensuring that the output of the PID controller at the switching moment completely matches the actual opening degree instruction of the three valves, avoiding the impact of valve action caused by sudden output change; then, the system starts a preset time period of delay logic, the specific time can be set according to the response characteristics of the system, during which the control signal and the valve state are continuously monitored to confirm that the system is in a stable state; after the delay ends, the system automatically switches the control mode from manual to automatic, and the PID controller starts to perform integral, differential and other dynamic adjustments according to the feedback deviation, formally entering the closed-loop operation.

[0029] In the embodiments of the present application, the stability and safety of the three-valve split-range control system during mode switching are significantly improved, the PID output is synchronized to the integrated valve position value, which fundamentally eliminates the control output jump during switching, realizes truly disturbance-free switching, avoids the dramatic fluctuation of process parameters caused by sudden opening or closing of the valve, and ensures the continuity of the production process and the safety of the equipment; secondly, the delay mechanism of a preset time period is introduced, which provides a buffer and confirmation window for the system, effectively filters the interference caused by signal jitter or human error, prevents mis-switching or control instability, and enhances the robustness of the system; the above method has clear operation logic and simple implementation, and can be completed only with basic control modules, having good universality and generalizability.

[0030] The application provides a three-valve split-range control hand-automatic seamless switching method. In a closed-loop automatic mode, the opening degrees of three valves are uniformly controlled by an output value of a PID controller according to a preset split-range control rule, complete forward control logic is established, and a basic mapping relationship is provided for subsequent realization of hand-automatic seamless switching. A comprehensive valve position value is introduced, a comprehensive valve position value is calculated by using a preset inverse operation rule based on current hand-opening degree instructions of the three valves, the inverse operation rule is established based on inverse solving of the split-range control rule, a single variable of the PID output value is inversely deduced from the multivariable of the three-valve opening degree instructions, intelligent pre-synchronization of the PID controller output value is realized, and the technical problem that the prior art cannot intelligently calculate the PID controller output value according to a hand state is solved. Finally, the output value of the PID controller is synchronized to the calculated comprehensive valve position value, mode switching is completed after a preset time period, continuity of control output in a switching instant is ensured, process disturbance caused by output jump is effectively avoided, and stability and reliability of the switching process are improved. The above method realizes seamless switching between hand-automatic modes of a three-valve system by constructing a complete technical chain of split-range control forward logic, inverse operation solving of a comprehensive valve position, PID output synchronization and time-delay switching, realizes intelligent synchronization of the PID controller output, eliminates switching disturbance, improves stability and safety of the control system, and enhances operation flexibility.

[0031] Specifically, in the above embodiment, the output range of the output value of the PID controller is -100% to 100%; the split-range control rule is that when the output value of the PID controller is -100% to 0%, the water supply valve is in an open state, and the first discharge valve and the second discharge valve are both in a fully closed state; when the output value of the PID controller is 0% to a first split-range point, the water supply valve and the first discharge valve are both in a closed state, and the second discharge valve is in an open state; when the output value of the PID controller is the first split-range point to a second split-range point, the water supply valve is in a closed state, and the first discharge valve and the second discharge valve are both in an open state; when the output value of the PID controller is the second split-range point to 100%, the water supply valve is in a closed state, the first discharge valve is in an open state, and the second discharge valve is in a fully open state; wherein 0% < the first split-range point < the second split-range point < 100%.

[0032] In the embodiment, the first split point is represented by y%, the second split point is represented by x%, and when the three-valve control circuit is in the closed-loop automatic mode, the output value of the PID controller in different interval ranges will trigger different valve action combinations, so as to realize accurate and efficient adjustment of the process parameter; specifically, the system is divided into multiple control intervals according to the size of the PID output signal, and each valve works according to the preset logic; when the PID output is negative, it indicates that the process parameter is low, and the liquid supplementing operation needs to be performed, at this time, the water supplementing valve is opened, and the two discharge valves are kept closed to avoid medium loss; when the PID output is in the interval of 0% to y%, it indicates that the system has a slight excess state, and small-flow discharge adjustment needs to be performed, at this time, the water supplementing valve is closed, the second discharge valve is gradually opened according to the output value to realize fine control, and the first discharge valve is still kept closed to ensure stable adjustment; when the PID output further increases to the interval of y% to x%, it indicates that the system needs larger-flow discharge, at this time, the second discharge valve continues to open, and the first discharge valve also starts to act, and the two discharge valves work cooperatively to ensure the adjustment response speed and control accuracy; when the PID output reaches the high-value interval of x% to 100%, it indicates that the system is in a serious excess state, and a large amount of medium needs to be quickly discharged, at this time, the second discharge valve is almost fully opened, and the first discharge valve is further opened according to the output value to undertake the main discharge task, realizing fast response. Through the above split logic, the system can automatically select the optimal valve combination under different working conditions, taking into account the adjustment accuracy at small flow and the response ability at large flow, significantly improving the adjustment range, stability and dynamic performance of the control system, and being especially suitable for industrial process control scenes with strict control quality requirements.

[0033] Specifically, in the above embodiment, the comprehensive valve position value is calculated by using a preset inverse operation rule, including: when the opening degree instruction of the manually set water supplementing valve is greater than 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening degree instruction of the water supplementing valve; when the opening degree instruction of the manually set water supplementing valve is equal to 0% and the opening degree instruction of the first discharge valve is greater than 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening degree instruction of the first discharge valve; and when the opening degree instruction of the manually set water supplementing valve is equal to 0% and the opening degree instruction of the first discharge valve is equal to 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening degree instruction of the second discharge valve.

[0034] When the three-valve control circuit is in the open-loop manual mode, an operator can manually set the opening degree instruction of the makeup valve, the first drain valve and the second drain valve according to the actual operation requirement. In order to ensure that the subsequent switching to the closed-loop automatic mode is realized without disturbance, an equivalent PID controller output value must be reversely calculated according to the current manual opening degree state of each valve through a preset logical rule. The value is referred to as a comprehensive valve position value. The comprehensive valve position value represents the initial output value that the PID controller should have if the automatic control is put into operation under the current manual valve opening degree, and is a key reference for realizing the disturbance-free switching. The calculation follows a clear priority logic. First, if the manual opening degree instruction of the makeup valve is greater than 0%, it indicates that the system is in a liquid supplementing condition. In this case, no matter how the states of other valves are, the opening degree of the makeup valve is taken as the basis to determine the comprehensive valve position value through the inverse operation according to the mapping relationship thereof in the split-range control. Second, if the opening degree of the makeup valve is 0% and the opening degree of the first drain valve is greater than 0%, it indicates that the system is in a large-flow discharging condition. In this case, the opening degree instruction of the first drain valve is taken to reversely calculate the corresponding PID output value as the comprehensive valve position. Finally, if the opening degrees of the makeup valve and the first drain valve are both 0% and only the second drain valve is open, the opening degree instruction of the second drain valve is taken to reversely calculate the comprehensive valve position value. The hierarchical judgment logic ensures that the PID output value meeting the automatic control rule can be uniquely and accurately back-calculated under any reasonable manual operation state, thereby providing a reliable basis for the subsequent output synchronization and mode switching, and thus guaranteeing the continuity and stability of the control process.

[0035] Specifically, in the above embodiment, the valve opening degrees of the three-valve execution module are determined to be in a switching-ready state, wherein the switching-ready state includes: when the opening degree instruction of the makeup valve is greater than 0%, the opening degree instruction of the first drain valve and the opening degree instruction of the second drain valve are both set to 0%; or when 0% < the opening degree instruction of the second drain valve ≤ the opening degree instruction of the second drain valve corresponding to the first split point, the opening degree instruction of the makeup valve and the opening degree instruction of the first drain valve are both set to 0%; or when the opening degree instruction of the second drain valve corresponding to the first split point < the opening degree instruction of the second drain valve ≤ 100%, the opening degree instruction of the first drain valve is set to the first target opening degree instruction corresponding to the opening degree instruction of the second drain valve in the closed-loop automatic mode, and the opening degree instruction of the makeup valve is set to 0%; or when 0% < the opening degree instruction of the first drain valve ≤ the opening degree instruction of the second drain valve corresponding to the second split point, the opening degree instruction of the second drain valve is set to the second target opening degree instruction corresponding to the opening degree instruction of the first drain valve in the closed-loop automatic mode, and the opening degree instruction of the makeup valve is set to 0%; or when the opening degree instruction of the second drain valve corresponding to the second split point < the opening degree instruction of the first drain valve ≤ 100%, the opening degree instruction of the second drain valve is set to 100%, and the opening degree instruction of the makeup valve is set to 0%.

[0036] In the actual operation process, in order to ensure the safety and non-perturbative of subsequent switching to the closed-loop automatic mode, the valve opening degree instruction manually set by the operator needs to follow a specific setting principle when the three-valve control loop is in the open-loop manual mode. The core requirement is that the manual opening degree of each valve must meet the normal operating state of the system under the automatic control logic before the closed-loop control is put into operation, so as to avoid logic conflicts or actuator action contradictions. The specific rules are as follows: if the preset water supply valve opening degree is greater than 0%, it indicates that the system is in a liquid supplementing working condition, at this time the first discharge valve and the second discharge valve must be set to 0% to prevent the medium from being simultaneously supplemented and discharged, causing control confusion; if only the second discharge valve is opened and its opening degree is within the range of the second discharge valve opening degree corresponding to 0% to y%, the water supply valve and the first discharge valve must be closed to ensure fine adjustment by the second discharge valve only; if the second discharge valve opening degree exceeds the value corresponding to y%, entering the interval of cooperative work with the first discharge valve, the opening degree of the first discharge valve needs to be set to a reasonable value corresponding to the closed-loop control under this working condition, and the water supply valve remains closed to match the cooperative adjustment logic under the automatic mode; conversely, if only the first discharge valve is opened and its opening degree is within the range of the second discharge valve opening degree corresponding to 0% to x%, the second discharge valve needs to be set to the opening degree value corresponding to the closed-loop operation under this working condition; when the first discharge valve opening degree further increases and exceeds the value corresponding to x%, it indicates that the system has entered the large-flow discharge stage, at this time the second discharge valve should be set to the 100% fully open state to ensure flow continuity and smooth transition. The above rules ensure the consistency of the manual state and the automatic logic.

[0037] It should be noted that for the complex working conditions involving the split range overlap area (y%~x%) in the above rules, due to the difficulty for the operator to accurately judge the matching relationship between the two valves, the system can provide intelligent auxiliary functions: when it is detected that the valve opening degree is in the cross-control interval, the reference opening degree value that the other valve should have is automatically calculated and output as an operation prompt to help the operator set a compliant valve position. This not only ensures the strictness of the switching conditions, but also improves the convenience and accuracy of human-machine interaction, effectively reduces the risk of misoperation, and ensures the stability and safety of the control system during the mode switching process.

[0038] Specifically, in the above embodiment, when it is determined that the valve opening degree of the three-valve execution module is not in the switching ready state, the three-valve control loop is stopped from being switched from the open-loop manual mode to the closed-loop automatic mode based on the preset prohibition rule.

[0039] Further, the preset prohibition rule includes a water supply valve prohibition to put into a closed-loop rule, a first discharge valve prohibition to put into a closed-loop rule, and a second discharge valve prohibition to put into a closed-loop rule.

[0040] Further, the prohibition of the water supply valve into the closed loop rule comprises: the opening degree instruction of the water supply valve is greater than 0%, and the opening degree instruction of the first discharge valve is greater than 0% or the opening degree instruction of the second discharge valve is greater than 0%.

[0041] Further, the prohibition of the first discharge valve into the closed loop rule comprises: the opening degree instruction of the second split point corresponding to the first discharge valve is greater than the opening degree instruction of the first discharge valve, the opening degree instruction of the first discharge valve is greater than 0%, and the opening degree instruction of the second discharge valve is not equal to the first target opening degree instruction or the opening degree instruction of the water supply valve is greater than 0%; or, the opening degree instruction of the first discharge valve is greater than the opening degree instruction of the second split point corresponding to the first discharge valve, and the opening degree instruction of the second discharge valve is less than 100% or the opening degree instruction of the water supply valve is greater than 0%.

[0042] Further, the prohibition of the second discharge valve into the closed loop rule comprises: the opening degree instruction of the first split point corresponding to the second discharge valve is greater than the opening degree instruction of the second discharge valve, the opening degree instruction of the second discharge valve is greater than 0%, and the opening degree instruction of the first discharge valve is greater than 0% or the opening degree instruction of the water supply valve is greater than 0%; or, the opening degree instruction of the second discharge valve is greater than the opening degree instruction of the first split point corresponding to the second discharge valve, and the opening degree instruction of the first discharge valve is not equal to the second target opening degree instruction or the opening degree instruction of the water supply valve is greater than 0%.

[0043] In the embodiment, in order to ensure the logic consistency and operation safety of the three-valve split control system when switching from the open loop manual mode to the closed loop automatic mode, prevent control conflicts or process disturbances caused by unreasonable valve opening degree settings, strict prohibition of closed loop conditions for the water supply valve, the first discharge valve and the second discharge valve are set, which are safety interlocking logics, real-time judge whether the current manual opening degree of each valve meets the process requirement of automatic control, if not, the system is prohibited to enter the closed loop operation, thereby effectively avoiding control instability caused by misoperation.

[0044] Specifically, the prohibition of the water supply valve into the closed loop condition is set as: when the opening degree of the water supply valve is greater than 0%, if any one of the first discharge valve or the second discharge valve is also in the open state, i.e. the opening degree is greater than 0%, the closed loop is prohibited, which ensures that the liquid supplementing and discharging operations cannot be performed at the same time, prevents the logic contradiction of supplementing and discharging at the same time, and guarantees the rationality of the process. For the first discharge valve, the prohibition conditions are divided into two categories: first, when the first discharge valve is in the interval cooperatively regulated with the second discharge valve, i.e. the opening degree is greater than 0% but does not exceed the x% corresponding value, it is required that the opening degree of the second discharge valve is consistent with the corresponding value in the closed loop state, and the water supply valve is closed, otherwise the closed loop is prohibited; second, when the opening degree of the first discharge valve exceeds the x% corresponding value and enters the high flow discharging stage, it is required that the second discharge valve must be in the 100% fully open state, and the water supply valve is closed, otherwise the closed loop is prohibited, which ensures that the system has sufficient flow capacity under high load discharging conditions, and avoids the throttling bottleneck caused by the small valve not being fully open.

[0045] For the second discharge valve, its prohibition conditions are also divided into two cases: first, when the second discharge valve is in the small flow regulation interval, i.e., the opening degree is greater than 0% but does not exceed the y% corresponding value, if the makeup valve or the first discharge valve is in the open state, the closed loop is prohibited to be put into operation, ensuring that the second discharge valve independently performs fine regulation; second, when the opening degree of the second discharge valve has entered the interval for cooperative work with the first discharge valve, i.e., exceeds the y% corresponding value, it is necessary to require that the opening degree of the first discharge valve matches the corresponding value in the closed loop state, and the makeup valve must be closed, otherwise the closed loop is prohibited to be put into operation, which ensures that in the cooperative work condition of the two valves, the two valves move in coordination, avoiding flow mutation caused by unmatched opening degrees.

[0046] The above prohibition conditions for putting into the closed loop constitute a complete safety verification mechanism, which can automatically identify manual settings that do not conform to the automatic control logic and prevent abnormal switching, significantly improving the safety, stability and operation reliability of the system. At the same time, the mechanism and the comprehensive valve position calculation logic complement each other, and together guarantee that the three-valve split-range control system realizes true disturbance-free switching in complex working conditions.

[0047] Specifically, in the above embodiment, the makeup valve, the first discharge valve and the second discharge valve are respectively provided with a hand controller module; the method further comprises: when the three-valve control loop is switched from the closed loop automatic mode to the open loop manual mode, the hand controller module locks and keeps the output value of the current PID controller as the manual output value, so as to maintain the opening degree command of the makeup valve, the first discharge valve and the second discharge valve unchanged.

[0048] In the present embodiment, in order to realize smooth transition of the three-valve split-range control system during mode switching, independent hand controller modules are respectively configured in the control loops of the makeup valve, the first discharge valve and the second discharge valve, and each hand controller module ensures the continuity of the valve opening degree and the stability of the control output when switching from the closed loop automatic mode to the open loop manual mode; specifically, when the operator switches the control mode of any valve from automatic to manual, the corresponding hand controller module will immediately lock and keep the output value of the PID controller at the switching moment, and take it as the initial output value of the valve in the manual mode, i.e., the manual output value, since the value is completely consistent with the automatic control output before switching, the opening degree command of the valve will not change before and after switching, thereby effectively avoiding valve jumping or process parameter fluctuation caused by mode switching; based on this, disturbance-free switching from closed loop to open loop is realized, ensuring the smoothness of the system during manual intervention, and at the same time, the configuration of independent hand controller modules for each valve avoids the logical complexity and operation coupling problems caused by the use of a unified total hand controller in the traditional scheme, making the operation more flexible and intuitive, and facilitating the operation personnel to independently regulate and control a single valve according to the actual working condition, thereby improving the operability and maintenance convenience of the system.

[0049] Those skilled in the art can understand that the modules or flows in the drawings are not necessarily required for implementing the present application. Those skilled in the art can understand that the modules in the devices in the implementation scenarios can be distributed in the devices in the implementation scenarios according to the description of the implementation scenarios, or can be changed to be located in one or more devices different from the implementation scenarios. The modules in the above implementation scenarios can be combined into one module, or can be further split into multiple sub-modules.

[0050] The above serial numbers of the present application are only for description, and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only some specific implementation scenarios of the present application, however, the present application is not limited thereto, and any variations that can be thought of by those skilled in the art shall fall within the protection scope of the present application.

Claims

1. A method for seamless switching between manual and automatic operation in a three-valve split-range control system, characterized in that, The method is applied to a three-valve control loop, which includes a PID controller and a three-valve execution module. The three-valve execution module includes a water supply valve, a first discharge valve, and a second discharge valve. The method includes: When the three-valve control loop is in closed-loop automatic mode, based on the split-range control rules set between the output value of the PID controller and the opening command of the three-valve execution module, the opening of the water supply valve, the first discharge valve and the second discharge valve are controlled simultaneously using the output value of the PID controller. When the three-valve control loop switches from open-loop manual mode to closed-loop automatic mode, the comprehensive valve position value is calculated using a preset inverse operation rule based on the opening command of the three-valve execution module currently set manually. The inverse operation rule is obtained by solving the split-range control rule in reverse. The output value of the PID controller is synchronized with the comprehensive valve position value, and the three-valve control loop is switched to closed-loop automatic mode after a preset time period.

2. The method according to claim 1, characterized in that, The output range of the PID controller is -100% to 100%; the split-range control rule is: When the output value of the PID controller is between -100% and 0%, the water supply valve is in the open state, and the first discharge valve and the second discharge valve are both in the fully closed state. When the output value of the PID controller is 0% to the first split point, both the water supply valve and the first discharge valve are closed, and the second discharge valve is open. When the output value of the PID controller is between the first split point and the second split point, the water supply valve is closed, and both the first discharge valve and the second discharge valve are open. When the output value of the PID controller is from the second split point to 100%, the water supply valve is closed, the first discharge valve is open, and the second discharge valve is fully open. Wherein, 0% < the first split point < the second split point < 100%.

3. The method according to claim 1 or 2, characterized in that, The calculation of the integrated valve position value using preset inverse operation rules includes: When the manually set opening command of the water supply valve is greater than 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening command of the water supply valve. When the manually set opening command of the water supply valve is equal to 0% and the opening command of the first discharge valve is greater than 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening command of the first discharge valve. When the manually set opening command of the water supply valve is 0% and the opening command of the first discharge valve is 0%, the comprehensive valve position value is determined based on the inverse operation result of the opening command of the second discharge valve.

4. The method according to claim 2, characterized in that, Before synchronizing the output value of the PID controller to the integrated valve position value, the method includes: The valve opening of the three-valve actuator module is determined to be in a switching ready state, wherein the switching ready state includes: When the opening command of the water supply valve is greater than 0%, the opening commands of both the first discharge valve and the second discharge valve are set to 0%. Alternatively, when 0% < the opening command of the second discharge valve ≤ the opening command of the second discharge valve corresponding to the first split point, both the opening command of the water supply valve and the opening command of the first discharge valve are set to 0%; Alternatively, when the opening command of the second discharge valve corresponding to the first split point is less than the opening command of the second discharge valve and less than 100%, the opening command of the first discharge valve is set to the first target opening command corresponding to the opening command of the second discharge valve in closed-loop automatic mode, and the opening command of the water supply valve is set to 0%. Alternatively, when 0% < the opening command of the first discharge valve ≤ the opening command of the second discharge valve corresponding to the second split point, the opening command of the second discharge valve is set to the second target opening command corresponding to the opening command of the first discharge valve in closed-loop automatic mode, and the opening command of the water supply valve is set to 0%; Alternatively, when the opening command of the second discharge valve corresponding to the second split point is less than the opening command of the first discharge valve and less than 100%, the opening command of the second discharge valve is set to 100%, and the opening command of the water supply valve is set to 0%.

5. The method according to claim 4, characterized in that, The method further includes: When it is determined that the valve opening of the three-valve actuator module is not in the switching ready state, the switching of the three-valve control loop from open-loop manual mode to closed-loop automatic mode is stopped based on the preset prohibition rule.

6. The method according to claim 5, characterized in that, The preset prohibition rules include a closed-loop rule prohibiting the water supply valve from being put into operation, a closed-loop rule prohibiting the first discharge valve from being put into operation, and a closed-loop rule prohibiting the second discharge valve from being put into operation.

7. The method according to claim 6, characterized in that, The rules prohibiting the water supply valve from being engaged in the closed-loop system include: The opening command of the water supply valve is greater than 0%, and the opening command of the first discharge valve is greater than 0% or the opening command of the second discharge valve is greater than 0%.

8. The method according to claim 6, characterized in that, The first discharge valve is prohibited from engaging closed-loop rules including: The opening command of the first discharge valve corresponding to the second split point is greater than the opening command of the first discharge valve, which is greater than 0%, and the opening command of the second discharge valve is not equal to the first target opening command, or the opening command of the water supply valve is greater than 0%. Alternatively, the opening command of the first discharge valve is greater than the opening command of the first discharge valve corresponding to the second split point, and the opening command of the second discharge valve is less than 100% or the opening command of the first water supply valve is greater than 0%.

9. The method according to claim 6, characterized in that, The second discharge valve is prohibited from being put into closed-loop operation according to the following rules: The opening command of the second discharge valve corresponding to the first split point is greater than the opening command of the second discharge valve, which is greater than 0%, and the opening command of the first discharge valve is greater than 0% or the opening command of the first water supply valve is greater than 0%. Alternatively, the opening command of the second discharge valve is greater than the opening command of the second discharge valve corresponding to the first split point, and the opening command of the first discharge valve is not equal to the second target opening command, or the opening command of the water supply valve is greater than 0.

10. The method according to claim 1, characterized in that, The water supply valve, the first discharge valve, and the second discharge valve are each equipped with a handheld device module; the method further includes: When the three-valve control loop switches from closed-loop automatic mode to open-loop manual mode, the hand controller module locks and maintains the current output value of the PID controller as the manual output value, thereby keeping the opening commands of the water supply valve, the first discharge valve, and the second discharge valve unchanged.

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