Calibration Method of Valve Position Feedback System

Abstract

The present invention provides a calibration method for a valve position feedback system, comprising: a valve position signal A / D conversion circuit, a processor, an APL encoder / decoder, a voltage control circuit, and a port input / output circuit. The valve position signal A / D conversion circuit is used to convert the valve position signal collected by the position sensor into a digital signal; the processor is used to obtain a real-time valve position digital signal according to the pre-calibrated valve full-open and full-close stroke range code value when the valve position signal is a data amount; the APL encoder / decoder is used to encode and process the real-time valve position digital signal to obtain an APL signal containing valve position information; the port input / output circuit is used to transmit the APL signal containing valve position information to the APL field switch, and transmit it to the central system via the APL field switch. Thus, the valve position sensor can be precisely controlled, and accurate feedback of the valve stroke position of the regulating valve and valve positioner can be achieved, and the wiring cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of valve control technology, and in particular to a calibration method for a valve position feedback system. Background Art

[0002] The control valve is the execution layer of the control loop, so in the process industry, it is necessary to control multiple control valves deployed on site.

[0003] At present, most valve positioners or control valves use (4mA to 20mA) current signal output to achieve valve position feedback. Due to the simple circuits such as signal shaping and filtering, their valve positioners often have problems such as unstable output current, low accuracy, large temperature drift, poor anti-interference, and high wiring costs when performing real-time feedback of valve position. Summary of the invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a calibration method for a valve position feedback system.

[0005] In a first aspect, the present application provides a valve position feedback system, including: a valve position signal A / D conversion circuit, a processor, an APL encoder / decoder, a voltage control circuit, and a port input / output circuit, wherein the APL is an advanced physical layer, wherein:

[0006] The valve position signal A / D conversion circuit is used to receive the valve position signal collected by the external valve position sensor, and convert the valve position signal into a digital signal and transmit it to the processor;

[0007] The processor is used to obtain a real-time valve position digital signal according to the pre-calibrated valve full-open and full-close stroke range code value when the valve position signal is a data amount, and transmit the real-time valve position digital signal to the APL codec;

[0008] The APL encoder / decoder is used to encode the real-time valve position digital signal to obtain an APL signal containing valve position information;

[0009] The port input-output circuit is used to transmit the APL signal containing the valve position information to the APL field switch, so that the APL field switch transmits the APL signal containing the valve position information to the central system.

[0010] Optionally, the system further comprises: a voltage control circuit, the voltage control circuit being electrically connected to the processor and the port input / output circuit respectively, and being used for converting a distribution voltage in an APL control signal from an APL field switch introduced by the port input / output circuit into an operating voltage of the processor;

[0011] The distribution voltage in the APL control signal is provided by an APL power switch, and the APL power switch superimposes the distribution voltage on the APL control signal sent by the central system.

[0012] Optionally, the valve position signal A / D conversion circuit includes: an A / D conversion chip, a 2.5V reference chip, and an anti-interference circuit, wherein:

[0013] The A / D conversion chip is used to convert the valve position signal collected by the valve position sensor from an analog voltage signal to a digital signal;

[0014] The 2.5V reference chip is used to provide a reference voltage for the A / D conversion chip and to power an external valve position sensor;

[0015] The anti-interference circuit is used to isolate external high-frequency signal interference.

[0016] Optionally, the port input and output circuit is communicatively connected to the APL field switch to receive Ethernet messages sent by the central system;

[0017] The APL codec is further used to decode the Ethernet message transmitted by the port input and output circuit to obtain the corresponding APL control signal, and transmit the decoded APL control signal to the processor;

[0018] The processor is also used to send the decoded APL control signal to the valve position sensor corresponding to the target valve through the valve position signal A / D conversion circuit according to the target address indicated by the Ethernet message, so that the valve position sensor can feed back the collected valve position signal to the valve position signal A / D conversion circuit after executing valve position signal collection.

[0019] Optionally, the port input and output circuit includes: a protection circuit, an anti-reverse connection circuit, and a signal / power isolation circuit.

[0020] The protection circuit is used to control the input voltage to be below a preset threshold;

[0021] The anti-reverse connection circuit is used for reverse connection protection;

[0022] The signal / power isolation circuit is used to isolate different signals and to isolate power supplies of different voltages.

[0023] Optionally, the processor is a CPU, and the CPU is a central processing unit;

[0024] The CPU communicates with the APL codec via a serial port;

[0025] The CPU is used to compare the digital signal sent by the valve position signal A / D conversion circuit with the pre-calibrated valve full open and full closed stroke range code value to obtain the corresponding real-time valve position digital signal, wherein the real-time valve position digital signal includes valve position percentage data.

[0026] Optionally, the above system further includes: a signal matching circuit, a filtering circuit,

[0027] The signal matching circuit is used to perform matching processing on the Ethernet message transmitted by the port input and output circuit;

[0028] The filtering circuit is used to filter the Ethernet messages transmitted by the port input and output circuit.

[0029] In a second aspect, an embodiment of the present application further provides a control method of a valve position feedback system, which uses the valve position feedback system described in any one of the first aspects to perform valve position feedback control, and the method includes:

[0030] The Ethernet message sent by the central system is transmitted to the port input and output circuit through the APL field switch, and the APL is an advanced physical layer;

[0031] Transmit Ethernet messages to the APL codec through the port input and output circuits;

[0032] The APL codec decodes the Ethernet message to obtain an APL control signal, and transmits the APL control signal to the processor;

[0033] The processor sends the APL control signal to the valve position sensor corresponding to the target valve according to the target address indicated by the Ethernet message, so that the valve position sensor performs valve position signal collection.

[0034] Optionally, before transmitting the Ethernet message sent by the central system to the port input and output circuit through the APL field switch, the method further includes:

[0035] Encapsulate the APL control signal output by the central system into Ethernet messages and transmit them to the APL power switch via a single twisted pair Ethernet cable;

[0036] The APL power switch superimposes the working power distribution on the Ethernet message and transmits it to the APL field switch.

[0037] Optionally, the method further comprises:

[0038] The valve position signal A / D conversion circuit receives the valve position signal collected by the external valve position sensor, converts the valve position signal into a digital signal and transmits it to the processor;

[0039] When the valve position signal is a data quantity, a real-time valve position digital signal is obtained by a processor according to a pre-calibrated valve full-open / full-close stroke range code value, and the real-time valve position digital signal is transmitted to an APL encoder / decoder;

[0040] The real-time valve position digital signal is encoded and processed by an APL encoder / decoder to obtain an APL signal containing valve position information;

[0041] The APL signal containing the valve position information is transmitted to the APL field switch through the port input and output circuit, so that the APL field switch transmits the APL signal containing the valve position information to the central system.

[0042] In a third aspect, an embodiment of the present application further provides a calibration method for a valve position feedback system, which is applied to the valve position feedback system described in any one of the first aspects, and the method includes:

[0043] Prompts that the valve position is in the fully closed state;

[0044] Instructing the processor to obtain the code value when the valve is fully closed through the serial port, and determining whether the code value when the valve is fully closed is within a first preset range;

[0045] If the code value when the valve is fully closed is not within the first preset range, the valve position sensor is adjusted to obtain the code value when the valve is fully closed again until the code value when the valve is fully closed is within the first preset range;

[0046] If the code value when the valve is fully closed is within the first preset range, it indicates that the valve position is in the fully open state;

[0047] Instructing the processor to obtain the code value when the valve is fully opened through the serial port, and determining whether the code value when the valve is fully opened is within a second preset range;

[0048] If the code value when the valve is fully opened is not within the second preset range, the code value when the valve is fully opened is obtained again after adjusting the valve stroke until the code value when the valve is fully opened is within the second preset range;

[0049] If the code value when the valve is fully open is within the second preset range, the code value of the travel range of the valve fully open or fully closed is saved, and the calibration is completed.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention is provided with a valve position feedback system including: a valve position signal A / D conversion circuit, a processor, an APL encoder / decoder, a voltage control circuit, and a port input / output circuit, wherein: the valve position signal A / D conversion circuit is used to receive the valve position signal collected by an external valve position sensor, and convert the valve position signal into a digital signal and transmit it to the processor; the processor is used to obtain a real-time valve position digital signal according to a pre-calibrated valve full-open / full-close stroke range code value when the valve position signal is a data amount, and transmit the real-time valve position digital signal to the APL encoder / decoder; the APL encoder / decoder is used to encode the real-time valve position digital signal to obtain an APL signal containing valve position information; the port input / output circuit is used to transmit the APL signal containing valve position information to the APL field switch, so that the APL field switch transmits the APL signal containing valve position information to the central system. This enables precise control of the valve position sensor and accurate feedback of the valve stroke position of the regulating valve and valve positioner. The use of APL technology only requires one twisted pair cable from the machine room to the site, which is then connected to each APL valve position feedback device through an APL site switch. This effectively solves the current problems of unstable output current, low accuracy, large temperature drift, poor anti-interference, and high wiring cost when the regulating valve and valve positioner provide real-time feedback on the valve position. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present invention will become more obvious:

[0053] Figure 1 It is a schematic diagram of the topology of the existing industrial control network;

[0054] Figure 2 A schematic diagram of the topological structure of an industrial control network for applying the valve position feedback system provided by an embodiment of the present application;

[0055] Figure 3 A schematic diagram of the structure of a valve position feedback system provided in an embodiment of the present application;

[0056] Figure 4 A flow chart of a control method of a valve position feedback system provided in an embodiment of the present application;

[0057] Figure 5A flow chart of a calibration method for a valve position feedback system provided in an embodiment of the present application;

[0058] In the figure:

[0059] 1-valve position signal A / D conversion circuit, 2-CPU, 3-APL encoder and decoder, 4-voltage control circuit, 5-port input and output circuit. DETAILED DESCRIPTION

[0060] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0061] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing or for circuit connection.

[0062] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0064] Figure 1 The topological structure diagram of the existing industrial control network is as follows: Figure 1 As shown, the (4-20mA) valve position feedback signal needs at least 2 wires from the field to the machine room for each device, and the wiring cost is very high. Figure 1The analog signal of the valve position sensor in the industrial control network shown is easily interfered by high-frequency signals, the signal restoration ability is poor, the output signal quality is low, the valve position feedback output signal is unstable, it is easy to affect the feedback output accuracy, and the temperature drift is large.

[0065] Figure 2 A schematic diagram of the topological structure of an industrial control network for applying the valve position feedback system provided by the embodiment of the present application is shown in FIG. Figure 2 As shown, the central system can be connected to the APL (Advanced Physical Layer) field switch through a single-pair Ethernet twisted pair cable. The APL field switch connects various APL valve position feedback systems (devices or equipment). The APL field switch transmits the Ethernet message of the central system to the APL valve position feedback system (device or equipment) corresponding to the target valve. Among them, only one twisted pair is needed from the APL equipment room to the site, which greatly reduces the wiring cost.

[0066] Exemplarily, the APL control signal of the central system is obtained, and the APL control signal is encapsulated into an Ethernet message and transmitted to the APL power switch through a single twisted pair Ethernet. The APL power switch is connected to the APL field switch after superimposing the working power distribution. The APL field switch controls each APL valve position feedback system through a single twisted pair, and provides the working power distribution to each valve position sensor. Among them, the Ethernet message is distributed to the valve position sensor corresponding to the target valve according to the target address indicated by it, so that the valve position sensor collects the valve position signal.

[0067] For example, after the valve position sensor collects the valve position signal, the valve position signal may be fed back to the central system along the original path.

[0068] Exemplarily, an embodiment of the present application provides a valve position feedback system, which may include: a valve position signal A / D conversion circuit, a processor, an APL encoder / decoder, a voltage control circuit, and a port input / output circuit, wherein the APL is an advanced physical layer, wherein: the valve position signal A / D conversion circuit is used to receive a valve position signal collected by an external valve position sensor, and convert the valve position signal into a digital signal and transmit it to the processor; the processor is used to obtain a real-time valve position digital signal according to a pre-calibrated valve full open / close stroke range code value when the valve position signal is a data amount, and transmit the real-time valve position digital signal to the APL encoder / decoder; the APL encoder / decoder is used to encode the real-time valve position digital signal to obtain an APL signal containing valve position information; the port input / output circuit is used to transmit the APL signal containing valve position information to the APL field switch, so that the APL field switch transmits the APL signal containing valve position information to the central system.

[0069] In this embodiment, the central system can be connected to the APL field switch via a single-pair Ethernet twisted-pair cable, and the APL field switch connects each valve position feedback system, thereby greatly reducing the wiring cost of the valve position feedback system and simplifying the system topology architecture of the valve position feedback system.

[0070] For example, it can be combined with Figure 2 As shown, a two-wire APL bus is used for communication between the machine room and the site (only one twisted pair is required). After arriving at the site, the APL field switch is used to communicate with each APL valve position feedback system (device or equipment).

[0071] Exemplarily, the valve position feedback system may further include: a voltage control circuit, which is electrically connected to the processor and the port input / output circuit, respectively, and is used to convert the distribution voltage in the APL control signal from the APL field switch introduced by the port input / output circuit into the operating voltage of the processor; wherein the distribution voltage in the APL control signal is provided by an APL power switch, and the APL power switch superimposes the distribution voltage on the APL control signal sent by the central system.

[0072] In this embodiment, when the power distribution voltage (9 to 15V) in the APL signal is converted into 3.3V, it can provide working power for the processor. In addition, the power distribution voltage (9 to 15V) in the APL signal can also be converted into the power supply voltage of the valve position sensor, thereby powering each valve position sensor.

[0073] Exemplarily, the valve position signal A / D conversion circuit includes: an A / D conversion chip, a 2.5V reference chip, and an anti-interference circuit, wherein: the A / D conversion chip is used to convert the valve position signal collected by the valve position sensor from an analog voltage signal into a digital signal; the 2.5V reference chip is used to provide a reference voltage for the A / D conversion chip and to power the external valve position sensor; the anti-interference circuit is used to isolate external high-frequency signal interference.

[0074] In this embodiment, an anti-interference circuit can be set at the input of the valve position signal (analog signal), thereby effectively suppressing high-frequency signal interference (such as intercom interference). A protection circuit can also be added to the port input and output circuit to solve the EMC problem. In addition, since a two-wire APL bus is used for Ethernet data transmission, it has good anti-interference and stability.

[0075] In this embodiment, a high-precision A / D conversion chip, a 2.5V reference chip, and an anti-interference circuit can be used to form the valve position signal A / D conversion circuit. Among them, the A / D conversion chip is (16 to 24) bits, so that the resolution of the signal can be ensured; after receiving the analog voltage (valve position feedback) signal, the A / D conversion chip converts it into a digital signal and transmits it to the processor. The 2.5V reference chip uses a low temperature drift and high-precision chip, which can provide a reference voltage for the A / D conversion chip. In addition, the 2.5V reference chip can also provide power for the external valve position sensor at the same time. The anti-interference circuit can ensure that the input signal is not interfered by high-frequency signals (such as walkie-talkies, etc.).

[0076] In this embodiment, in addition to using a low-power, high-precision A / D conversion chip, a high-precision sampling circuit and a low-temperature drift device can also be used in the valve position sensor, so that the output signal accuracy can reach one ten-thousandth, and the temperature drift can reach <±0.3µA / ℃. This ensures that the valve position feedback device has high accuracy of the valve position signal in an environment of -40℃~80℃ and achieves a small temperature drift.

[0077] Exemplarily, the port input and output circuit is communicatively connected with the APL field switch for receiving Ethernet messages sent by the central system; the APL encoder and decoder is further used to decode the Ethernet messages transmitted by the port input and output circuit to obtain corresponding APL control signals, and transmit the decoded APL control signals to the processor; the processor is further used to send the decoded APL control signal to the valve position sensor corresponding to the target valve through the valve position signal A / D conversion circuit according to the target address indicated by the Ethernet message, so that the valve position sensor feeds back the collected valve position signal to the valve position signal A / D conversion circuit after executing valve position signal collection.

[0078] In this embodiment, multiple valve position sensors on site can be remotely controlled through Ethernet messages sent by the central system, and after the valve position sensors collect valve position signals, the valve position signals are fed back to the central system in real time.

[0079] Exemplarily, the port input and output circuit includes: a protection circuit, an anti-reverse connection circuit, and a signal / power isolation circuit. The protection circuit is used to control the input voltage below a preset threshold; the anti-reverse connection circuit is used to perform reverse protection; the signal / power isolation circuit is used to isolate different signals and isolate power supplies of different voltages.

[0080] In this embodiment, by setting a protection circuit, an anti-reverse connection circuit, and a signal / power isolation circuit in the port input and output circuit, overvoltage and reverse protection can be achieved, meeting EMC-related standards and 1000V withstand voltage requirements.

[0081] In this embodiment, a signal matching circuit, a filtering circuit, a protection circuit, etc. may also be provided on the periphery of the APL codec, so as to ensure the reliability and integrity of the signal.

[0082] Exemplarily, the processor is a central processing unit (CPU); the CPU is communicatively connected to the APL codec via a serial port.

[0083] In this embodiment, in addition to using the CPU, other low-power processors can also be used, and the function implemented is: comparing the digital signal sent by the valve position signal A / D conversion circuit with the pre-calibrated valve full open and full closed stroke range code value to obtain the corresponding real-time valve position digital signal, wherein the real-time valve position digital signal includes valve position percentage data.

[0084] Exemplarily, the valve position feedback system may further include: a signal matching circuit and a filtering circuit, wherein the signal matching circuit is used to perform matching processing on the Ethernet message transmitted by the signal access circuit; and the filtering circuit is used to perform filtering processing on the Ethernet message transmitted by the signal access circuit.

[0085] Figure 3 A schematic diagram of a valve position feedback system provided in an embodiment of the present application is shown in FIG. Figure 3 As shown, it may include: a valve position signal A / D conversion circuit 1, a CPU2, an APL encoder / decoder 3, a voltage control circuit 4, and a port input / output circuit 5. An external valve position sensor inputs an analog valve position signal, and transmits a digital signal to the CPU2 through the valve position signal A / D conversion circuit 1. If the valve position sensor outputs data volume, it directly communicates with the CPU2. The CPU2 calls the previously calibrated valve full-open and full-close stroke range code value to output the corresponding real-time valve position digital signal, and then communicates with the APL encoder / decoder 3 through the serial port. The real-time valve position digital signal is encoded by the APL encoder / decoder 3 and sent to the APL field switch through the port input / output circuit 5, and finally transmitted to the central system via the APL field switch.

[0086] In this embodiment, APL technology (Advanced Physical Layer Ethernet, whose greatest features are long cable distance, intrinsic safety and application-level protocol support to achieve maximum productivity and output) is used to realize the control of the on-site valve position sensor by the system center, which effectively solves the problems of unstable output current, low accuracy, large temperature drift, poor anti-interference and high wiring cost when the current regulating valve and valve positioner provide real-time feedback on the valve position.

[0087] For example, Figure 4As shown, the embodiment of the present application further provides a control method of a valve position feedback system, which can be applied to the above-mentioned valve position feedback system for valve position feedback control, and the method comprises the following steps:

[0088] Step S401: The Ethernet message sent by the central system is transmitted to the port input and output circuit through the APL field switch.

[0089] Exemplarily, the APL control signal output by the central system can be encapsulated into an Ethernet message and transmitted to the APL power switch via a single twisted pair Ethernet cable. The APL power switch then superimposes the working power distribution on the Ethernet message and transmits it to the APL field switch.

[0090] Step S402: Transmit the Ethernet message to the APL codec through the port input and output circuit.

[0091] In this embodiment, the APL codec decodes the Ethernet message transmitted by the port input and output circuit to obtain an APL control signal that can be recognized by the processor.

[0092] Step S403: The Ethernet message is decoded by the APL codec to obtain an APL control signal, and the APL control signal is transmitted to the processor.

[0093] In this embodiment, the processor parses the decoded APL control signal to obtain a control instruction that can be recognized by the valve position sensor, wherein the control instruction is used to control the valve position sensor to collect the valve position signal.

[0094] Step S404: the processor sends the APL control signal to the valve position sensor corresponding to the target valve according to the target address indicated by the Ethernet message, so that the valve position sensor performs valve position signal collection.

[0095] In this embodiment, the target address of the Ethernet message corresponds to the valve position sensor, and the processor transmits the control instruction for the valve position sensor to the corresponding valve position sensor through the valve position signal A / D conversion circuit to control the valve position sensor to collect the valve position signal.

[0096] Exemplarily, the above method may further include the following steps:

[0097] Before the Ethernet message sent by the central system is transmitted to the port input and output circuit through the APL field switch, the APL control signal output by the central system is encapsulated into an Ethernet message and transmitted to the APL power switch through a single twisted pair Ethernet cable; after the working power distribution is superimposed on the Ethernet message by the APL power switch, it is transmitted to the APL field switch.

[0098] Exemplarily, the above method may further include the following steps:

[0099] The valve position signal collected by the external valve position sensor is received through the valve position signal A / D conversion circuit, and the valve position signal is converted into a digital signal and then transmitted to the processor; when the valve position signal is a data amount, the processor obtains a real-time valve position digital signal according to the pre-calibrated valve full open and full closed stroke range code value, and transmits the real-time valve position digital signal to the APL encoder and decoder; the real-time valve position digital signal is encoded and processed by the APL encoder and decoder to obtain an APL signal containing valve position information; the APL signal containing valve position information is transmitted to the APL field switch through the port input and output circuit, so that the APL field switch transmits the APL signal containing valve position information to the central system.

[0100] The steps in this embodiment show the process of the valve position sensor feeding back the valve position signal to the central system. After the central system sends the APL control signal for each valve position sensor on site through the Ethernet message, the valve position signal collected by each valve position sensor on site can also be obtained in real time through the original route.

[0101] In this embodiment, the APL technology is used to realize the control of the on-site valve position feedback system by the system center. It can be connected to the APL on-site switch through a single-pair Ethernet twisted-pair cable, and the APL on-site switch is used to connect each valve position feedback system. Only one twisted-pair cable is needed from the machine room to the site. After arriving at the site, it is connected to each valve position feedback system through the APL on-site switch, thereby realizing the digital transmission of the valve position signal. In addition, by adopting a two-wire APL bus, only an APL power switch and an APL on-site switch are needed to directly transmit the valve position signal to the central system. This greatly reduces the wiring cost of the valve position feedback system, and well solves the problems of unstable output current, low accuracy, large temperature drift, poor anti-interference, and high wiring cost when the current regulating valve and valve positioner perform real-time feedback on the valve position.

[0102] For example, Figure 5 A flow chart of a calibration method for a valve position feedback system provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, since the strokes of the regulating valves are different, in order to ensure the high accuracy of the valve position feedback output signals of each regulation, the stroke parameters of each valve feedback system need to be calibrated before use. The following steps may be included:

[0103] Prompt that the valve position is in a fully closed state; obtain the code value when the valve is fully closed through the serial port instruction processor, and determine whether the code value when the valve is fully closed is within the first preset range; if the code value when the valve is fully closed is not within the first preset range, adjust the valve position sensor and re-obtain the code value when the valve is fully closed until the code value when the valve is fully closed is within the first preset range; if the code value when the valve is fully closed is within the first preset range, prompt that the valve position is in a fully open state; obtain the code value when the valve is fully open through the serial port instruction processor, and determine whether the code value when the valve is fully open is within the second preset range; if the code value when the valve is fully open is not within the second preset range, adjust the valve stroke and re-obtain the code value when the valve is fully open until the code value when the valve is fully open is within the second preset range; if the code value when the valve is fully open is within the second preset range, save the valve stroke range code value, and the calibration is completed.

[0104] In this embodiment, when the calibration starts, the valve is first controlled to be in a fully closed state. The upper computer software enables the CPU to obtain the code value when the valve is fully closed through the serial port, and the CPU processor determines whether the code value is within a reasonable range. If it is not within the reasonable range, the valve position sensor is adjusted to make the code value within the reasonable range; if it is within the reasonable range, the valve continues to be in a fully open state; further, the upper computer software enables the CPU to obtain the code value when the valve is fully open through the serial port, and the CPU determines whether the code value is within the reasonable range. If it is not within the reasonable range, it means that the valve stroke is out of range, and the valve stroke is adjusted. If it is within the reasonable range, the linearization parameters are calculated, the calibration data is saved, and the calibration is exited.

[0105] In this embodiment, before the valve position feedback system feeds back the valve position signal, software calibration is first performed, thereby improving the feedback accuracy of the valve position signal.

[0106] The above is the core idea of ​​the present invention. In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0107] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

[0108] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A calibration method for a valve position feedback system, characterized in that: Applied in a valve position feedback system, the method comprises: Prompts that the valve position is in the fully closed state; Instructing the processor to obtain the code value when the valve is fully closed through the serial port, and determining whether the code value when the valve is fully closed is within a first preset range; If the code value when the valve is fully closed is not within the first preset range, the valve position sensor is adjusted to obtain the code value when the valve is fully closed again until the code value when the valve is fully closed is within the first preset range; If the code value when the valve is fully closed is within the first preset range, it indicates that the valve position is in the fully open state; Instructing the processor to obtain the code value when the valve is fully opened through the serial port, and determining whether the code value when the valve is fully opened is within a second preset range; If the code value when the valve is fully opened is not within the second preset range, the code value when the valve is fully opened is obtained again after adjusting the valve stroke until the code value when the valve is fully opened is within the second preset range; If the code value when the valve is fully open is within the second preset range, the code value of the travel range of the valve fully open or fully closed is saved, and the calibration is completed; The valve position feedback system includes: a valve position signal A / D conversion circuit, a processor, an APL encoder / decoder, a voltage control circuit, and a port input / output circuit. The APL is an advanced physical layer, wherein: The valve position signal A / D conversion circuit is used to receive the valve position signal collected by the external valve position sensor, and convert the valve position signal into a digital signal and transmit it to the processor; The processor is used to obtain a real-time valve position digital signal according to the pre-calibrated valve full-open and full-close stroke range code value when the valve position signal is a data amount, and transmit the real-time valve position digital signal to the APL codec; The APL encoder / decoder is used to encode the real-time valve position digital signal to obtain an APL signal containing valve position information; The port input-output circuit is used to transmit the APL signal containing the valve position information to the APL field switch, so that the APL field switch transmits the APL signal containing the valve position information to the central system.

2. The calibration method of the valve position feedback system according to claim 1, characterized in that: The valve position feedback system also includes: voltage control circuit, The voltage control circuit is electrically connected to the processor and the port input / output circuit respectively, and is used to convert the distribution voltage in the APL control signal from the APL field switch introduced by the port input / output circuit into the working voltage of the processor; The distribution voltage in the APL control signal is provided by an APL power switch, and the APL power switch superimposes the distribution voltage on the APL control signal sent by the central system.

3. The calibration method of the valve position feedback system according to claim 1, characterized in that: The valve position signal A / D conversion circuit includes: an A / D conversion chip, a 2.5V reference chip, and an anti-interference circuit, wherein: The A / D conversion chip is used to convert the valve position signal collected by the valve position sensor from an analog voltage signal to a digital signal; The 2.5V reference chip is used to provide a reference voltage for the A / D conversion chip and to power an external valve position sensor; The anti-interference circuit is used to isolate external high-frequency signal interference.

4. The calibration method of the valve position feedback system according to any one of claims 1 to 3, characterized in that: The port input and output circuit is connected to the APL field switch for receiving Ethernet messages sent by the central system; The APL codec is further used to decode the Ethernet message transmitted by the port input and output circuit to obtain the corresponding APL control signal, and transmit the decoded APL control signal to the processor; The processor is also used to send the decoded APL control signal to the valve position sensor corresponding to the target valve through the valve position signal A / D conversion circuit according to the target address indicated by the Ethernet message, so that the valve position sensor can feed back the collected valve position signal to the valve position signal A / D conversion circuit after executing valve position signal collection.

5. The calibration method of the valve position feedback system according to any one of claims 1 to 3, characterized in that: The port input and output circuit includes: a protection circuit, an anti-reverse connection circuit, and a signal / power isolation circuit. The protection circuit is used to control the input voltage to be below a preset threshold; The anti-reverse connection circuit is used for reverse connection protection; The signal / power isolation circuit is used to isolate different signals and to isolate power supplies of different voltages.

6. The calibration method of the valve position feedback system according to any one of claims 1 to 3, characterized in that: The processor is a CPU, which is a central processing unit; The CPU communicates with the APL codec via a serial port; The CPU is used to compare the digital signal sent by the valve position signal A / D conversion circuit with the pre-calibrated valve full open and full closed stroke range code value to obtain the corresponding real-time valve position digital signal, wherein the real-time valve position digital signal includes valve position percentage data.

7. The calibration method of the valve position feedback system according to any one of claims 1 to 3, characterized in that: The valve position feedback system also includes: signal matching circuit, filter circuit, The signal matching circuit is used to perform matching processing on the Ethernet message transmitted by the port input and output circuit; The filtering circuit is used to filter the Ethernet messages transmitted by the port input and output circuit.

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