Intelligent valve positioner and control method thereof

Abstract

The application relates to an intelligent valve positioner and a control method, which comprise a shell, an air inlet and outlet seat, a circuit board, a piezoelectric valve module and a display and key module are arranged in the shell, the air inlet and outlet seat is provided with an air inlet channel, an air outlet channel and a pressure gauge; the circuit board is integrated with a power supply and a signal input module and a microprocessor, a two-wire 4-20mA direct current signal is adopted to realize control instructions and system power supply at the same time; a main shaft, a driving gear and a feedback rod are arranged in the shell, a valve position is fed back in real time through gear meshing to drive an angle sensor, gear clutching and angle adjustment are realized in cooperation with a torsion spring; the microprocessor is integrated with a closed-loop control, calibration, fault diagnosis, PST partial stroke test and three-break protection units, and supports switching and partial stroke control of multiple flow characteristics. The positioner realizes accurate positioning of a valve, low air source consumption, one-key calibration and multiple safety protection, simplifies the adjustment process, is suitable for single / dual-acting actuators, and greatly improves the accuracy and stability of industrial valve control.

Description

Technical Field

[0001] This invention relates to the field of industrial automation valve control, specifically to an intelligent valve positioner and its control method. Background Technology

[0002] Valve positioners are core actuators for regulating valve opening in industrial automation control systems. Traditional pneumatic valve positioners suffer from drawbacks such as low control accuracy, slow response speed, and high air consumption. Conventional intelligent positioners often use three-wire / four-wire power supply, resulting in complex wiring and poor compatibility. They also have problems such as cumbersome calibration procedures, lack of partial stroke testing functions, imperfect protection mechanisms against air / power / signal interruptions, and inconvenient angle sensor calibration.

[0003] In addition, traditional positioners cannot adapt to various flow characteristic switching, are prone to valve position oscillation in small-capacity actuators, and have the risk of dead zone failure in angle detection, making it difficult to meet the high-precision, high-reliability, and easy-to-maintain control requirements of valves in industries such as chemical, petroleum, and power.

[0004] Therefore, we propose an intelligent valve positioner and its control method to solve the above problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an intelligent valve positioner and its control method.

[0006] This invention provides an intelligent valve positioner, comprising a housing and an inlet / outlet air seat. The housing contains a circuit board, a piezoelectric valve module, and a display and button module. The inlet and outlet air seats are fixed on one side of the housing. The inlet and outlet air seats are provided with an inlet channel and an outlet channel, and are equipped with pressure gauges to detect the pressure of the inlet and outlet channels. The inlet and outlet channels are connected to the corresponding interfaces of the piezoelectric valve module. The inlet channel is connected to an external air source, and the outlet channel is connected to an external actuator. The circuit board integrates a power supply and signal input module and a microprocessor. The power supply and signal input module receives a two-wire 4-20mA DC current signal, which also serves as a control command and system power supply. The microprocessor is electrically connected to the power supply and signal input module, the piezoelectric valve module, and the display and button module. It is used to analyze the set valve position percentage, receive valve position feedback signals, and drive the piezoelectric valve module. The housing contains a rotatably connected main shaft. One end of the main shaft is fixed to a drive gear, and the other end extends out of the housing and is fixed to a feedback rod, which engages with the actuator drive rod. The housing also contains a rotatably connected shaft. One end of the shaft is fixed to a mounting plate, on which an angle sensor is fixed. The output end of the angle sensor is fixed to a driven gear, and the drive gear meshes with the driven gear. A torsion spring is fitted onto the shaft, with both ends of the spring engaging with the housing and the mounting plate, respectively. The angle sensor is electrically connected to a microprocessor, which detects the actual displacement of the actuator in real time and converts it into angle or stroke values.

[0007] Preferably, the mounting plate is integrally equipped with a dial plate, and the housing has a relief hole for finger avoidance at the position opposite the dial plate. The dial plate can drive the gear clutch of the angle sensor and adjust the angle.

[0008] Preferably, the piezoelectric valve module is a single-acting or double-acting type; the single-acting type corresponds to one air outlet, and the double-acting type corresponds to two air outlets; an adjustable flow switch is provided at the air outlet channel to adjust the output air flow rate, and the number of air outlet channels is the same as the number of air outlets.

[0009] Preferably, the display and button module includes an LCD display screen and operation buttons, the operation buttons including at least an OK button, a page up button, a cancel button, a one-click automatic calibration button, and a one-click zero-point calibration button.

[0010] Preferably, the angle sensor is a single-turn high-precision potentiometer with an effective angle detection range of 5°~105°, and the microprocessor is configured with sensor angle dead zone protection logic.

[0011] Preferably, the microprocessor integrates a closed-loop control unit, a calibration unit, a fault diagnosis unit, a PST partial stroke test unit, and a three-break protection unit; when the positioner valve position is stable, the piezoelectric valve module closes the air circuit, and the air consumption is <0.1m³ / h; the three-break protection unit supports position holding or reset actions under air outage, power outage, and signal outage; the calibration unit supports one-click automatic calibration, manual calibration, and rapid zero-point calibration.

[0012] Preferably, the microprocessor supports switching between linear, equal percentage, fast-opening, and custom 20-point curve flow characteristics, as well as split-range control, valve position tight-closing control, and valve position feedback direction configuration.

[0013] A control method for an intelligent valve positioner, applied to an intelligent valve positioner, includes the following steps: S1: Signal Acquisition: The power and signal input module receives a two-wire 4-20mA DC current signal, and the microprocessor converts the current signal into a set valve position percentage. S2: Valve position feedback: The actuator drives the feedback rod to rotate the main shaft and the drive gear. The driven gear and the angle sensor rotate synchronously, converting the actual valve position into an electrical signal and feeding it back to the microprocessor. S3: Closed-loop regulation: The microprocessor compares the deviation between the set valve position and the actual valve position, outputs a pulse signal to drive the piezoelectric valve module, adjusts the air pressure and flow rate of the inlet / outlet air channel, and controls the actuator action; S4: Steady-state hold: When the deviation is 0, the microprocessor shuts off the piezoelectric valve module's air output, and the valve position remains stable.

[0014] Preferably, the following steps are also included: S5: Automatic calibration process: The microprocessor automatically detects the actuator's direction of motion, locates the zero point and full position, detects the charging and venting time, performs leakage tests and valve parameter optimization, and automatically saves the parameters after calibration; S6: Quick Zero Point Calibration: When 4mA is input, there is no air pressure in the outlet channel and the actual valve position is zero, one-key zero point calibration is triggered, and the microprocessor directly corrects the zero point value of the angle sensor. S7: PST Partial Stroke Test: The microprocessor executes partial stroke actions according to the set start point, target point, interval time, and number of cycles, and judges the valve position response time and position error in real time. If there is an abnormality, it will automatically return to the original position and record the fault code. S8: Airflow regulation: The output airflow is adjusted by the adjustable flow switch in the outlet air channel, and the microprocessor helps to eliminate valve position oscillation of small-capacity actuators.

[0015] Preferably, it also includes the following steps: S9: Flow characteristic control: The microprocessor maps the 4-20mA input signal to a linear, equal percentage, fast-opening, or custom curve valve position output according to the configuration; S10: Tight-close control: When the valve position reaches the preset low / high threshold, the microprocessor controls the piezoelectric valve module to fully vent / fully charge, thereby achieving tight-close of the valve. S11: Includes segmented control: The microprocessor executes valve position control in segments according to 4-12mA, 12-20mA or a user-defined range; S12: Includes fault diagnosis and protection: The microprocessor monitors the gas source, angle sensor, piezoelectric valve module, shell temperature, and valve position oscillation status in real time, and displays fault codes when a fault is triggered; it performs position retention or reset when gas / power / signal is cut off; S13: Includes sensor angle protection: When the microprocessor detects that the angle sensor has entered the 5°~105° dead zone, it prompts for angle reset to ensure effective valve position detection.

[0016] Compared with related technologies, the present invention provides the following beneficial effects: Simplified power supply and wiring: It uses a two-wire 4-20mA signal to simultaneously supply power and transmit commands, eliminating the need for additional power cables, making it compatible with existing industrial control systems and reducing installation costs.

[0017] High positioning accuracy: Gear meshing angle feedback + high-precision potentiometer, combined with closed-loop control, results in small valve position positioning error, no gas consumption in steady state, and significant energy saving effect.

[0018] Easy to adjust: One-click automatic calibration and quick zero-point calibration, combined with paddle-type gear clutch adjustment, angle correction can be completed without disassembling the machine.

[0019] Comprehensive functions: integrates PST partial stroke testing, three-break protection, multi-flow characteristic switching, split-range control, and fault diagnosis to meet the needs of complex working conditions.

[0020] Highly adaptable: Supports single / double-acting actuators, adjustable current switch eliminates oscillation in small-capacity actuators, and has high versatility. Attached Figure Description

[0021] Figure 1 This is an exploded view of the intelligent valve positioner of the present invention; Figure 2 This is a schematic diagram illustrating the working principle of the present invention; Figure 3 This is a schematic diagram showing the disassembled feedback rod and main shaft of the present invention; Figure 4 This is a schematic diagram of the feedback rod structure of the present invention; Figure 5 This is a wiring diagram of the input and feedback terminals of the present invention; Figure 6 This is a wiring diagram of the limit switch terminals of the present invention; Figure 7 An angle diagram of the angle sensor of the present invention; Figure 8 This is the feedback measurement wiring diagram for the present invention; Figure 9 This is a flow characteristic curve diagram of the present invention; Figure 10 This is a block diagram of the control method of the present invention; Figure 11 This is a schematic diagram showing the relative positions of the clearance holes in this invention; Figure 12 This is a block diagram of the circuit board and modules on the circuit board according to the present invention.

[0022] The diagram shows the following components: 1. Housing; 2. Inlet / Outlet Seats; 3. Circuit Board; 4. Piezoelectric Valve Module; 5. Display and Button Module; 6. Inlet Channel; 7. Outlet Channel; 8. Pressure Gauge; 9. Power and Signal Input Module; 10. Microprocessor; 11. Spindle; 12. Drive Gear; 13. Feedback Rod; 14. Shaft; 15. Mounting Plate; 16. Angle Sensor; 17. Driven Gear; 18. Torsion Spring; 19. Toggle Plate; 20. Clearance Hole; 22. Adjustable Flow Switch; 23. LCD Display; 24. Operation Buttons; 26. Closed-Loop Control Unit; 27. Calibration Unit; 28. Fault Diagnosis Unit; 29. ​​PST Partial Stroke Test Unit; 30. Three-Way Protection Unit. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Please refer to the following: Figures 1 to 12 A smart valve positioner includes a housing 1 and an inlet / outlet air seat 2. The housing 1 houses a circuit board 3, a piezoelectric valve module 4, and a display and button module 5. The inlet and outlet air seat 2 is fixed to one side of the housing 1. The inlet and outlet air seat 2 is provided with an inlet channel 6 and an outlet channel 7, and a pressure gauge 8 is installed to detect the pressure of the inlet channel 6 and the outlet channel 7. The inlet channel 6 and the outlet channel 7 are connected to the corresponding interfaces of the piezoelectric valve module 4. The inlet channel 6 is connected to an external air source, and the outlet channel 7 is connected to an external actuator. The circuit board 3 integrates a power and signal input module 9 and a microprocessor 10. The power and signal input module 9 receives a two-wire 4-20mA DC current signal, which also serves as a control command and system power supply. The microprocessor 10 is electrically connected to the power and signal input module 9, the piezoelectric valve module 4, and the display and button module 5, and is used to analyze the set valve position percentage, receive valve position feedback signals, and drive the piezoelectric valve module 4. The main shaft 11 is rotatably connected inside the housing 1. One end of the main shaft 11 is fixedly connected to the drive gear 12, and the other end extends out of the housing 1 and is fixedly connected to the feedback rod 13. The feedback rod 13 cooperates with the actuator drive rod. The rotating shaft 14 is also rotatably connected inside the housing 1. One end of the rotating shaft 14 is fixedly connected to the mounting plate 15. An angle sensor 16 is fixed on the mounting plate 15. The output end of the angle sensor 16 is fixedly connected to the driven gear 17. The drive gear 12 meshes with the driven gear 17. A torsion spring 18 is sleeved on the rotating shaft 14. The two ends of the torsion spring 18 are respectively engaged with the housing 1 and the mounting plate 15. The angle sensor 16 is electrically connected to the microprocessor 10 to detect the actual displacement of the actuator in real time and convert it into angle or stroke value.

[0025] The mounting plate 15 is integrally equipped with a dial plate 19. The housing 1 has a relief hole 20 for finger avoidance at the position opposite to the dial plate 19. The dial plate 19 can drive the gear of the angle sensor 16 to engage and disengage and adjust the angle.

[0026] The piezoelectric valve module 4 is either single-acting or double-acting; the single-acting type corresponds to one air outlet, and the double-acting type corresponds to two air outlets; an adjustable flow switch 22 is provided at the air outlet channel 7 to adjust the output air flow rate, and the number of air outlet channels 7 is the same as the number of air outlets.

[0027] The display and button module 5 includes an LCD display screen 23 and operation buttons 24. The operation buttons 24 include at least an OK button, a page up button, a cancel button, a one-click automatic calibration button, and a one-click zero-point calibration button.

[0028] The angle sensor 16 is a single-turn high-precision potentiometer with an effective angle detection range of 5°~105°. The microprocessor 10 is configured with sensor angle dead zone protection logic.

[0029] The microprocessor 10 integrates a closed-loop control unit 26, a calibration unit 27, a fault diagnosis unit 28, a PST partial stroke test unit 29, and a three-break protection unit 30. When the positioner valve is stable, the piezoelectric valve module 4 closes the air path, and the air consumption is <0.1m³ / h. The three-break protection unit 30 supports position holding or reset actions under air outage, power outage, and signal outage. The calibration unit 27 supports one-click automatic calibration, manual calibration, and rapid zero-point calibration.

[0030] The microprocessor 10 supports switching between linear, equal percentage, fast-opening, and custom 20-point curve flow characteristics, as well as split-range control, valve position tight-closing control, and valve position feedback direction configuration.

[0031] A control method for an intelligent valve positioner, applied to an intelligent valve positioner, characterized by comprising the following steps: S1: Signal Acquisition: The power and signal input module 9 receives a two-wire 4-20mA DC current signal, and the microprocessor 10 converts the current signal into a set valve position percentage. S2: Valve position feedback: The actuator drives the feedback rod 13 to rotate the main shaft 11 and the drive gear 12. The driven gear 17 and the angle sensor 16 rotate synchronously, converting the actual valve position into an electrical signal and feeding it back to the microprocessor 10. S3: Closed-loop regulation: The microprocessor 10 compares the deviation between the set valve position and the actual valve position, outputs a pulse signal to drive the piezoelectric valve module 4, adjusts the air pressure and flow rate of the air inlet channel 6 / air outlet channel 7, and controls the actuator action; S4: Steady-state hold: When the deviation is 0, the microprocessor 10 shuts off the air output of the piezoelectric valve module 4, and the valve position remains stable.

[0032] It also includes, S5: Automatic calibration process: The microprocessor 10 automatically detects the actuator's direction of motion, locates the zero point and full position, detects the charging and venting time, performs leakage tests and valve parameter optimization, and automatically saves the parameters after calibration; S6: Quick Zero Point Calibration: When the input is 4mA, there is no air pressure in the air outlet channel 7 and the actual valve position is zero, one-key zero point calibration is triggered, and the microprocessor 10 directly corrects the zero point value of the angle sensor 16. S7: PST Partial Stroke Test: Microprocessor 10 executes partial stroke actions according to the set start point, target point, interval time, and number of cycles, and judges the valve position response time and position error in real time. If there is an abnormality, it automatically returns to the original position and records the fault code. S8: Airflow regulation: The output airflow is adjusted by the adjustable flow switch 22 of the air outlet channel 7, and the microprocessor 10 works together to eliminate valve position oscillation of small-capacity actuators.

[0033] Also includes S9: Flow characteristic control: Microprocessor 10 maps 4-20mA input signals to linear, equal percentage, fast-opening, or custom curve valve position outputs as configured; S10: Tight-close control: When the valve position reaches the preset low / high threshold, the microprocessor 10 controls the piezoelectric valve module 4 to fully exhaust / fully fill the valve to achieve tight closure. S11: Split-range control: Microprocessor 10 executes valve position control in segments according to 4-12mA, 12-20mA or a user-defined range; S12: Fault Diagnosis and Protection: The microprocessor 10 monitors the gas source, angle sensor 16, piezoelectric valve module 4, shell temperature, and valve position oscillation status in real time. When a fault is triggered, a fault code is displayed. When gas / power / signal is cut off, position retention or reset is performed. S13: Sensor angle protection: When the microprocessor 10 detects that the angle sensor 16 has entered the dead zone of 5°~105°, it prompts for angle reset to ensure that the valve position detection is effective.

[0034] Pneumatic circuit and electronic control structure The inlet / outlet seat 2 has a built-in inlet channel 6 and an outlet channel 7, which are connected to an external air source and actuator. The pressure gauge 8 monitors the inlet and outlet pressures in real time, facilitating on-site debugging and troubleshooting. The piezoelectric valve module 4 serves as the core of the air circuit actuation and is available in single / double-acting types to match different actuator structures. The adjustable flow switch 22 in the outlet channel 7 can finely adjust the air flow rate and suppress valve position oscillations in small-capacity actuators.

[0035] Circuit board 3 serves as the control core. The power and signal input module 9 receives a two-wire 4-20mA signal and simultaneously handles power supply and command parsing. The microprocessor 10 coordinates all functional units, eliminating the need for independent power supplies and simplifying system wiring. The display and button module 5 uses the LCD screen 23 to display valve position, pressure, and fault codes in real time, while the operation buttons 24 enable quick operations such as one-click calibration and parameter configuration.

[0036] Valve position feedback and adjustment structure The main shaft 11 passes through the housing 1. The outer feedback rod 13 is linked to the actuator drive rod, and the inner driving gear 12 meshes with the driven gear 17 of the angle sensor 16, converting the linear displacement of the actuator into an angle signal. The torsion spring 18 ensures the gears are in constant engagement, guaranteeing feedback accuracy. By moving the dial plate 19 through the clearance hole 20 in the housing 1, the gears can be disengaged or engaged, allowing for quick zero-point / stroke adjustment of the angle sensor 16 without disassembling the equipment.

[0037] The angle sensor 16 uses a single-turn high-precision potentiometer, which can effectively detect angles from 5° to 105°. The microprocessor 10 has built-in dead-zone protection logic, which will immediately prompt a reset when the angle exceeds the range to avoid detection failure.

[0038] Control method implementation process Basic control process Signal acquisition: After a 4-20mA signal is input, the microprocessor 10 converts it into the set valve position percentage; Valve position feedback: The actuator drives the feedback rod 13 to rotate, and the angle sensor 16 outputs the actual valve position electrical signal; Closed-loop regulation: The microprocessor 10 compares the deviation and outputs pulses to drive the piezoelectric valve module 4 to regulate the air pressure; Steady-state maintenance: When the deviation is 0, the piezoelectric valve air circuit is closed, the air consumption is <0.1m³ / h, and the valve position is stable.

[0039] Advanced Functional Flow Automatic calibration: The microprocessor 10 automatically identifies actuator parameters, completes leak testing, and optimizes parameters; Quick zero-point calibration: With a 4mA signal and zero valve position, the sensor zero point can be corrected with one click; PST Partial Stroke Test: Performs partial stroke action according to set parameters to diagnose valve response performance in real time; Flow characteristics and segmented control: Freely switchable linear / equal percentage / fast opening characteristics, supporting segmented signal control; Fault and Protection: Real-time monitoring of system status, automatic hold / reset under three failure conditions to ensure system safety.

[0040] Detailed design optimization The toggle plate 19 works with the clearance hole 20 to achieve tool-less angle adjustment; the adjustable flow switch 22 is compatible with actuators of different capacities; the single / double-acting piezoelectric valve module is compatible with most industrial actuators; angle dead zone protection and valve position tight-closing control further improve equipment reliability and control accuracy.

[0041] Function Introduction 1. Trip Type Valve stroke selection: linear stroke or 1Turn is rotary stroke. The factory default is linear stroke.

[0042] This parameter is automatically determined during automatic or manual calibration. When feedback is detected when the lever changes from zero to end point or the spindle rotation angle is less than 70 degrees, it is set to Way; otherwise, it is set to Turn when the angle exceeds 70 degrees.

[0043] 2. Sensor angle The valve position sensor is a single-turn high-precision potentiometer. The positioner converts its resistance range into an angle display, with an effective angle range of 0~110°, and a practical application range of 5~105° (e.g., Figure 7 (As shown). Because the potentiometer has a dead zone, to avoid entering the dead zone during operation and thus failing to detect the position, its initial angle value needs to be set. According to the setting, when the valve moves from the zero point to the end point, if the positioner spindle or feedback rod rotates clockwise, the angle change is incremental. At this time, the initial angle of the sensor must be set to a small angle value, and it must be ensured that the angle does not exceed 105° at the end point; conversely, if the spindle or feedback rod rotates counterclockwise, the angle change is decremental. At this time, the initial angle of the sensor must be set to a small angle value, and it must be ensured that the angle is not less than 5° at the end point.

[0044] Angle setting principles (see P30 for sensor angle setting method, and see the appendix on page 34 for angle value setting reference range): Linear stroke: The stroke angle range is required to be 20~70°, and the initial angle can be set to 10~30 (clockwise) or 70~90 (counterclockwise).

[0045] Angular travel: The travel angle is 90°. The initial angle can be set to 5~15° (clockwise) or 95~105° (counterclockwise).

[0046] 3. Automatic calibration The automatic calibration and debugging mode will automatically detect the zero point, end point, travel direction, and optimize parameters after execution.

[0047] 4. Manual calibration In manual calibration and debugging mode, you will need to manually set the valve zero point and end point position, and then the parameters will be automatically optimized.

[0048] 5. Manual Operation Mode In manual operation mode, the valve can be switched on and off using the arrow keys.

[0049] 6. Sensitivity Sensitivity is the responsiveness to changes in valve position signals. The factory default value is 0.5%, and the sensitivity value will be automatically set according to the current valve condition after automatic / manual calibration. The manually adjustable range is AUTO, 0.1%~10%. A lower sensitivity value results in higher accuracy but is more prone to instability. When valve friction is high and fluctuations occur, the sensitivity value can be appropriately increased.

[0050] 7. Signal control direction The 4~20mA DC control direction is set to upward by default, but both upward and downward directions can be set. The direction will be automatically determined after automatic / manual calibration.

[0051] Rise: The air pressure at port P1 rises as the signal increases.

[0052] Decrease: P1 airway pressure decreases as the signal increases.

[0053] 8. PV direction Valve position display direction setting: the factory default is 4~20mA corresponding to 0~100%, which can be set to rise or fall.

[0054] Rise: 4~20mA corresponds to a display range of 0%~100%. Decrease: 4~20mA corresponds to a display of 100~0%. 9. Position feedback direction Valve position feedback direction setting: The default output is 4~20mA when the valve position is 0~100%. It can be set to 4~20mA or 20~4mA.

[0055] 10. Feedback Calibration Valve position feedback signal calibration. When there is a deviation in the output current of the feedback signal at valve positions of 0% and 100%, this parameter can be entered to manually calibrate the zero and end point current of the feedback signal. Press Figure 8 Connect the ammeter to measure the current, and then adjust the current by entering the following parameters (the current will change accordingly when the feedback value changes).

[0056] Feedback Zero Point: Feedback zero point value (MvZero), which corresponds to the feedback value at 0% of the valve position zero point.

[0057] Feedback Endpoint: The feedback endpoint (MvEnd) corresponds to the feedback value at 100% of the valve position endpoint.

[0058] 11. Flow characteristic curve The flow characteristics, the relationship between the input signal and the valve position percentage, are linear by default. The following characteristic curves can be selected: Lines: Straight lines 1:25: Equal percentage flow curve 1:33: Equal percentage flow curve 1:50: Equal percentage flow curve 25:1: Fast-opening flow curve: 33:1: Fast-opening flow curve: 50:1: Fast-opening flow curve: UserSet: User-defined traffic curve (20-point curve).

[0059] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An intelligent valve positioner, comprising a housing (1) and an inlet / outlet air seat (2), characterized in that: The housing (1) is equipped with a circuit board (3), a piezoelectric valve module (4), and a display and button module (5); the inlet and outlet air seat (2) is fixed on one side of the housing (1). The inlet and outlet air seat (2) is provided with an inlet channel (6) and an outlet channel (7), and a pressure gauge (8) is installed to detect the pressure of the inlet channel (6) and the outlet channel (7); the inlet channel (6) and the outlet channel (7) are connected to the corresponding interfaces of the piezoelectric valve module (4). The inlet channel (6) is connected to an external air source, and the outlet channel (7) is connected to an external actuator. The circuit board (3) integrates a power supply and signal input module (9) and a microprocessor (10). The power supply and signal input module (9) receives a two-wire 4-20mA DC current signal, which also serves as a control command and system power supply. The microprocessor (10) is electrically connected to the power supply and signal input module (9), the piezoelectric valve module (4), and the display and button module (5), and is used to analyze the set valve position percentage, receive the valve position feedback signal, and drive the piezoelectric valve module (4). The main shaft (11) is rotatably connected inside the housing (1). One end of the main shaft (11) is fixed to the drive gear (12), and the other end passes through the housing (1) and is fixed to the feedback rod (13). The feedback rod (13) cooperates with the actuator drive rod. The rotating shaft (14) is also rotatably connected inside the housing (1). One end of the rotating shaft (14) is fixed to the mounting plate (15). An angle sensor (16) is fixed on the mounting plate (15). The output end of the angle sensor (16) is fixed to the driven gear (17). The drive gear (12) meshes with the driven gear (17). The rotating shaft (14) is fitted with a torsion spring (18). The two ends of the torsion spring (18) are respectively engaged with the housing (1) and the mounting plate (15). The angle sensor (16) is electrically connected to the microprocessor (10) to detect the actual displacement of the actuator in real time and convert it into angle or stroke value.

2. The intelligent valve positioner according to claim 1, characterized in that, The mounting plate (15) is integrally equipped with a dial plate (19). The housing (1) has a relief hole (20) for finger avoidance at the position opposite to the dial plate (19). The dial plate (19) can drive the gear of the angle sensor (16) to engage and disengage and adjust the angle.

3. The intelligent valve positioner according to claim 1, characterized in that, The piezoelectric valve module (4) is either single-acting or double-acting; the single-acting type corresponds to one air outlet, and the double-acting type corresponds to two air outlets; an adjustable flow switch (22) is provided at the air outlet channel (7) to adjust the output air flow rate, and the number of air outlet channels (7) is the same as the number of air outlets.

4. The intelligent valve positioner according to claim 1, characterized in that, The display and button module (5) includes an LCD display screen (23) and operation buttons (24). The operation buttons (24) include at least an OK button, a page up button, a cancel button, a one-click automatic calibration button, and a one-click zero-point calibration button.

5. The intelligent valve positioner according to claim 1, characterized in that, The angle sensor (16) is a single-turn high-precision potentiometer with an effective detection angle range of 5°~105°. The microprocessor (10) is configured with sensor angle dead zone protection logic.

6. The intelligent valve positioner according to claim 1, characterized in that, The microprocessor (10) integrates a closed-loop control unit (26), a calibration unit (27), a fault diagnosis unit (28), a PST partial stroke test unit (29), and a three-break protection unit (30). When the positioner valve is stable, the piezoelectric valve module (4) closes the air path, and the air consumption is <0.1m³ / h. The three-break protection unit (30) supports position holding or reset actions under air break, power break, and signal break conditions. The calibration unit (27) supports one-click automatic calibration, manual calibration, and fast zero-point calibration.

7. The intelligent valve positioner according to claim 6, characterized in that, The microprocessor (10) supports switching of flow characteristics such as linear, equal percentage, fast opening, and custom 20-point curve, as well as split-range control, valve position tight-closing control, and valve position feedback direction configuration.

8. A control method for an intelligent valve positioner, applied to the intelligent valve positioner according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Signal acquisition: The power and signal input module (9) receives a two-wire 4-20mA DC current signal, and the microprocessor (10) converts the current signal into a set valve position percentage; S2: Valve position feedback: The actuator drives the feedback rod (13) to rotate the main shaft (11) and the drive gear (12), and the driven gear (17) rotates synchronously with the angle sensor (16) to convert the actual valve position into an electrical signal and feed it back to the microprocessor (10). S3: Closed-loop regulation: The microprocessor (10) compares the deviation between the set valve position and the actual valve position, outputs a pulse signal to drive the piezoelectric valve module (4), adjusts the air pressure and flow rate of the inlet channel (6) / outlet channel (7), and controls the actuator action; S4: Steady-state hold: When the deviation is 0, the microprocessor (10) shuts off the piezoelectric valve module (4) air path output, and the valve position remains stable.

9. The control method according to claim 8, characterized in that, It also includes the following steps: S5: Automatic calibration process: The microprocessor (10) automatically detects the actuator's direction of motion, locates the zero point and full position, detects the charging and venting time, performs leakage tests and valve parameter optimization, and automatically saves the parameters after calibration; S6: Quick zero-point calibration: When the input is 4mA, there is no air pressure in the outlet channel (7) and the actual valve position is zero, one-key zero-point calibration is triggered, and the microprocessor (10) directly corrects the zero-point value of the angle sensor (16). S7: PST Partial Stroke Test: The microprocessor (10) executes partial stroke actions according to the set start point, target point, interval time, and number of cycles, and judges the valve position response time and position error in real time. If there is an abnormality, it automatically returns to the position and records the fault code. S8: Airflow regulation: The output airflow is adjusted by the adjustable flow switch (22) of the air outlet channel (7), and the microprocessor (10) works together to eliminate valve position oscillation of small capacity actuators.

10. The control method according to claim 9, characterized in that, It also includes the following steps: S9: Flow characteristic control: The microprocessor (10) maps the 4-20mA input signal to a linear, equal percentage, fast-opening or custom curve valve position output as configured; S10: Tight-close control: When the valve position reaches the preset low / high threshold, the microprocessor (10) controls the piezoelectric valve module (4) to fully exhaust / fully fill the valve to achieve tight closure; S11: Split-range control: The microprocessor (10) performs valve position control in segments according to 4-12mA, 12-20mA or a user-defined range; S12: Fault diagnosis and protection: The microprocessor (10) monitors the gas source, angle sensor (16), piezoelectric valve module (4), shell temperature, and valve position oscillation status in real time. When a fault is triggered, the fault code is displayed; when the gas / power / signal is cut off, the position is maintained or the system is reset. S13: Sensor angle protection: When the microprocessor (10) detects that the angle sensor (16) enters the dead zone of 5°~105°, it prompts for angle reset to ensure that the valve position detection is effective.

Images