Servo liquid level meter transmitter

Abstract

The utility model discloses a servo liquid level meter transmitter, and belongs to the field of liquid level measuring equipment. Dynamic data of liquid in a liquid container are measured through a measuring unit, and the dynamic data comprise floater change data and liquid change trend data; acquiring temperature data and pressure data of liquid in the liquid container by using an acquisition unit; performing temperature compensation based on the temperature data by adopting a processing unit, performing pressure compensation based on the pressure data, and generating a control instruction according to the dynamic data; and executing corresponding operation through an execution unit according to the control instruction. The temperature and pressure data are compensated through the processing unit, so that the influence of thermal expansion and cold contraction of liquid and density change on the measurement precision is solved, and the long-term stability is improved; according to dynamic data detected by the measuring unit, the processing unit is utilized to generate a control instruction based on the dynamic data, so that accurate multiple judgment on liquid level change is realized, and the accuracy and the reliability of measurement are improved.

Description

Technical Field

[0001] This utility model relates to the field of liquid level measurement equipment, specifically to a servo liquid level transmitter. Background Technology

[0002] Liquid level measurement technology has wide applications in industrial production, environmental monitoring, and energy management. With the continuous improvement of industrial automation, higher requirements are being placed on the accuracy, stability, and reliability of liquid level measurement. Servo level gauges, as a commonly used liquid level measurement device, are widely used in industries such as petrochemicals, pharmaceuticals, and food processing due to their high measurement accuracy and wide applicability.

[0003] Currently, common level gauges on the market mainly include float-type level gauges, magnetostrictive level gauges, and photoelectric level gauges. Among them, the Hall effect electric float level transmitter converts changes in liquid level into corresponding Hall voltage signals through a float, torsion tube system, and Hall sensor system. After sampling and data processing by the transmitter, this signal is transmitted to the host computer in a 4-20mA or HART bus signal mode. Although this type of level gauge overcomes the mechanical wear problem of traditional electric float level transmitters, it still has certain limitations in terms of nonlinear measurement, power consumption, and accuracy.

[0004] Photoelectric level gauges are another common type of liquid level measurement device. They use a constant force spring to convert changes in liquid level into the rotation angle of a concentric shaft, which is then converted into a pulse signal by a laser encoder. This replaces the measuring wire in traditional servo level gauges, improving the durability of the measuring device. However, this type of level gauge is not adaptable to complex working conditions, especially in environments with large temperature and pressure variations, where measurement accuracy is easily affected.

[0005] Magnetostrictive level gauges are a new type of level measurement device. Their modular design completely isolates the core components from the process medium, extending their service life. Some improved models are also equipped with thermocouples and pressure transmitters to compensate for measurement errors caused by changes in the density of the measured liquid with temperature. However, there is still room for improvement in the high-precision measurement capabilities of these level gauges, especially in scenarios requiring real-time response to rapid changes in liquid level.

[0006] However, existing liquid level gauge technology still has some shortcomings in practical applications: First, the existing technology is not fast enough to respond to dynamic changes in liquids and it is difficult to reflect the trend of liquid level changes in real time; second, it lacks comprehensive consideration of environmental factors such as temperature and pressure, resulting in insufficient stability and reliability of measurement results under complex working conditions.

[0007] Therefore, there is an urgent need to develop a servo level transmitter that can measure liquid level with high precision, respond to liquid level changes in real time, and comprehensively consider the effects of temperature and pressure factors, so as to meet the high requirements of modern industry for liquid level measurement. Utility Model Content

[0008] To address the problems of poor measurement accuracy, lack of compensation mechanisms for temperature and pressure changes, and poor long-term stability of liquid level measurement in existing technologies, a servo liquid level transmitter is provided that achieves high-precision and high-stability liquid level measurement and can compensate for temperature and pressure changes.

[0009] This application provides a servo level transmitter for use in liquid containers, comprising:

[0010] A measuring unit is used to measure dynamic data of the liquid in the liquid container, the dynamic data including float change data and liquid change trend data;

[0011] The acquisition unit is used to acquire temperature and pressure data of the liquid in the liquid container;

[0012] The processing unit, connected to the measurement unit and the acquisition unit respectively, is used to perform temperature compensation based on the temperature data, pressure compensation based on the pressure data, and generate control commands based on the dynamic data;

[0013] An execution unit, connected to the processing unit, is used to perform corresponding operations according to the control instructions.

[0014] Optionally, the measurement unit includes:

[0015] A torque detection module is used to measure the torque signal of the float in the liquid container;

[0016] Hall effect detection module for detecting displacement signals of the float in the liquid container;

[0017] A photoelectric detection module, the output of which is connected to the first input of the processing unit, is used to detect the liquid change trend data in the liquid container;

[0018] The analog-to-digital conversion module has a first input terminal connected to the output terminal of the torque detection module, a second input terminal connected to the output terminal of the Hall effect detection module, and an output terminal connected to the second input terminal of the processing unit. The analog-to-digital conversion module is used to convert the torque signal into torque data and the displacement signal into displacement data.

[0019] Optionally, the torque detection module includes:

[0020] A torque sensor is used to collect torque information of the float in the liquid container;

[0021] A first amplifier is connected to the output of the torque sensor, and its output forms the output of the torque detection module. The first amplifier is used to filter and amplify the torque information to obtain the torque signal.

[0022] Optionally, the Hall detection module includes:

[0023] At least one Hall sensor is used to collect the displacement information of the float;

[0024] At least one second amplifier, the number of which is the same as the number of the Hall sensors, and each second amplifier corresponds to one Hall sensor. The input terminal of the second amplifier is connected to the output terminal of the associated Hall sensor, and the output terminal of the second amplifier serves as the output terminal of the Hall detection module. The second amplifier is used to filter and amplify the displacement information to obtain the displacement signal.

[0025] Optionally, the Hall detection module includes: 7 Hall sensors and 7 second amplifiers.

[0026] Optionally, the photoelectric detection module includes:

[0027] At least one photoelectric sensor is used to detect the trend information of liquid change in the liquid container;

[0028] At least one amplitude converter, the number of amplitude converters being the same as the number of photoelectric sensors, and each amplitude converter corresponding to one photoelectric sensor, the input terminal of the amplitude converter being connected to the output terminal of the associated photoelectric sensor, the output terminal of the amplitude converter serving as the output terminal of the photoelectric detection module, the amplitude converter being used to convert the liquid change trend information into liquid change trend data with a preset voltage.

[0029] Optionally, the photoelectric detection module includes two photoelectric sensors and two amplitude converters.

[0030] Optionally, the acquisition unit includes:

[0031] A temperature sensor is used to collect the temperature signal of the liquid in the liquid container;

[0032] A third amplifier is connected to the output of the temperature sensor, and its output is connected to the processing unit. The third amplifier is used to filter and amplify the temperature signal to obtain the temperature data.

[0033] A pressure sensor is used to acquire the pressure signal of the liquid in the liquid container;

[0034] A fourth amplifier is provided, the input of which is connected to the output of the pressure sensor, and the output of which is connected to the processing unit. The fourth amplifier is used to filter and amplify the pressure signal to obtain the pressure data.

[0035] Optionally, the execution unit includes:

[0036] An isolation module, the input of which is connected to the processing unit, is used to isolate and amplify the control commands to obtain control information;

[0037] A control module, the input of which is connected to the output of the isolation module, is used to generate a drive signal based on the control information;

[0038] The motor has its input terminal connected to the output terminal of the control module, and the motor performs corresponding operations according to the drive signal.

[0039] Optional, also includes:

[0040] A human-computer interaction module, connected to the processing unit, is used to receive input signals and display the temperature data, the pressure data, the float change data, and the liquid change trend data.

[0041] The power supply module is connected to the measurement unit, the acquisition unit, the processing unit, the execution unit, and the human-machine interaction module, respectively, and is used to supply power to the measurement unit, the acquisition unit, the processing unit, the execution unit, and the human-machine interaction module.

[0042] The beneficial effects of the above technical solution are as follows:

[0043] This application discloses a servo level transmitter applied in a liquid container. A measuring unit measures dynamic data of the liquid within the container, including float change data and liquid trend data. An acquisition unit collects temperature and pressure data of the liquid. A processing unit performs temperature compensation based on the temperature data and pressure compensation based on the pressure data, generating control commands based on the dynamic data. An execution unit then executes the corresponding operations according to the control commands. By processing and compensating for temperature and pressure data, the impact of thermal expansion and contraction and density changes on measurement accuracy is mitigated, improving long-term stability. Furthermore, the dynamic data detected by the measuring unit, combined with the control commands generated by the processing unit, enables precise multi-level judgment of liquid level changes, enhancing measurement accuracy and reliability. Attached Figure Description

[0044] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0045] Figure 1 This is a schematic diagram of a module of a first embodiment of the servo level transmitter described in this application;

[0046] Figure 2 This is a schematic diagram of another embodiment of the servo level transmitter described in this application;

[0047] Figure 3 This is a circuit diagram of the analog-to-digital conversion module described in this application;

[0048] Figure 4 This is a schematic diagram of one embodiment of the torque detection module described in this application;

[0049] Figure 5 This is a schematic diagram of one embodiment of the Hall detection module described in this application;

[0050] Figure 6 This is a circuit diagram of the second amplifier in this application;

[0051] Figure 7 This is a schematic diagram of one embodiment of the photoelectric detection module described in this application;

[0052] Figure 8 This is a circuit diagram of the amplitude converter described in this application;

[0053] Figure 9 This is a circuit diagram of the control module of this application. Detailed Implementation

[0054] The advantages of this application are further illustrated below with reference to the accompanying drawings and specific embodiments.

[0055] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0056] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0057] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0058] In the description of this application, it should be understood that the numerical labels before the steps do not indicate the order of the steps, but are only used to facilitate the description of this application and to distinguish each step, and therefore should not be construed as a limitation of this application.

[0059] The servo level transmitter of this application can be applied in fields such as petrochemical industry (storage tank level monitoring), warehousing and logistics (liquefied natural gas), water treatment, power (e.g., boiler water level), food, and pharmaceuticals (fermentation tanks). The measuring unit measures dynamic data of the liquid in the container, including float change data and liquid trend data. The acquisition unit collects temperature and pressure data of the liquid in the container. The processing unit performs temperature compensation based on the temperature data and pressure compensation based on the pressure data, generating control commands based on the dynamic data. The execution unit executes the corresponding operations according to the control commands. By processing and compensating for temperature and pressure data, the impact of thermal expansion and contraction and density changes on measurement accuracy is resolved, improving long-term stability. The dynamic data detected by the measuring unit, combined with the control commands generated by the processing unit, enables precise multi-level judgment of liquid level changes, improving measurement accuracy and reliability.

[0060] Example 1

[0061] See Figure 1 As shown, this application provides a servo level transmitter that is applied in a liquid container. The servo level transmitter may include: a measurement unit 1, a data acquisition unit 2, a processing unit 3, and an execution unit 4.

[0062] Measurement unit 1 is used to measure dynamic data of the liquid in the liquid container, the dynamic data including float change data and liquid change trend data;

[0063] Acquisition unit 2 is used to acquire temperature and pressure data of the liquid in the liquid container;

[0064] Processing unit 3 is connected to measuring unit 1 and acquisition unit 2 respectively, and is used to perform temperature compensation based on temperature data, pressure compensation based on pressure data, and generate control commands according to dynamic data;

[0065] The execution unit 4 is connected to the processing unit 3 and is used to perform corresponding operations according to the control instructions.

[0066] In this embodiment, the processing unit 3 is composed of a high-performance ARM processor STM32F407ZET6, a crystal oscillator, a ferroelectric memory, resistors, and capacitors. It can quickly process sensor data, perform data analysis, and respond rapidly to control, achieving the purpose of liquid level measurement. The processing unit 3 can employ a PID control algorithm to calculate the control quantity based on the deviation between the liquid level setpoint and the actual measured value, achieving precise liquid level control. The processing unit 3 also has a data storage function, which can record historical data for easy later analysis and processing.

[0067] In this embodiment, the servo level transmitter measures dynamic data of the liquid in the liquid container through the measurement unit 1. This dynamic data includes float change data and liquid change trend data. The acquisition unit 2 collects temperature and pressure data of the liquid in the container. The processing unit 3 performs temperature compensation based on the temperature data and pressure compensation based on the pressure data, and generates control commands based on the dynamic data. The execution unit 4 executes the corresponding operations according to the control commands. By processing and compensating for temperature and pressure data, the influence of thermal expansion and contraction and density changes of the liquid on measurement accuracy is resolved, improving long-term stability. The dynamic data detected by the measurement unit 1, combined with the control commands generated by the processing unit 3, enables precise multi-level judgment of liquid level changes, improving the accuracy and reliability of the measurement.

[0068] Example 2

[0069] See Figures 2-8 As shown, in this embodiment, the measurement unit 1 may include: a torque detection module 11, a Hall effect detection module 12, a photoelectric detection module 13, and an analog-to-digital conversion module 14.

[0070] Torque detection module 11 is used to measure the torque signal of the float in the liquid container;

[0071] Among them, see Figure 4 The torque detection module 11 may include a torque sensor 111 and a first amplifier 112.

[0072] Torque sensor 111 is used to collect torque information of the float in the liquid container;

[0073] A first amplifier 112 is connected to the output of the torque sensor 111. The output of the first amplifier 112 forms the output of the torque detection module 11. The first amplifier 112 is used to filter and amplify the torque information to obtain the torque signal.

[0074] In this embodiment, the torque sensor 111 is a strain gauge torque sensor with a range of 0N-100N and an accuracy of 0.1%FS. The first amplifier 112 adopts a dual operational amplifier differential amplifier circuit with a gain of 100 times and a bandwidth of 0kHz-1kHz. It has a low-pass filter function, which can effectively filter out high-frequency interference signals.

[0075] Hall effect detection module 12 is used to detect the displacement signal of the float in the liquid container;

[0076] Among them, see Figure 5 and Figure 6The Hall detection module 12 may include: at least one Hall sensor 121 and at least one second amplifier 122;

[0077] At least one Hall sensor 121 is used to collect the displacement information of the float;

[0078] At least one second amplifier 122, the number of second amplifiers 122 being the same as the number of Hall sensors 121, and each second amplifier 122 corresponding to one Hall sensor 121, the input terminal of the second amplifier 122 being connected to the output terminal of the associated Hall sensor 121, the output terminal of the second amplifier 122 serving as the output terminal of the Hall detection module 12, and the second amplifier 122 being used to filter and amplify the displacement information to obtain the displacement signal.

[0079] In a preferred embodiment, the Hall detection module 12 may include: seven Hall sensors 121 and seven second amplifiers 122.

[0080] In this embodiment, seven Hall sensors 121 are evenly distributed along the float's trajectory. Each Hall sensor 121 has a detection range of 10 mm, and the spacing between adjacent Hall sensors 121 is 8 mm, forming a continuous displacement detection area. The Hall sensors 121 employ linear Hall elements with a sensitivity of 5 mV / Gauss and a linearity of 0.5%. The second amplifier 122 uses a single-stage amplifier circuit with a gain of 50 times and a bandwidth of 0 Hz-500 Hz. It also features bandpass filtering to remove power frequency interference and high-frequency noise.

[0081] The photoelectric detection module 13 is connected to the first input terminal of the processing unit 3. The photoelectric detection module 13 is used to detect the liquid change trend data in the liquid container.

[0082] Among them, see Figure 7 and Figure 8 The photoelectric detection module 13 may include at least one photoelectric sensor 131 and at least one amplitude converter 132.

[0083] At least one photoelectric sensor 131 is used to detect the liquid change trend information in the liquid container;

[0084] At least one amplitude converter 132, the number of amplitude converters 132 being the same as the number of photoelectric sensors 131, and each amplitude converter 132 corresponding to one photoelectric sensor 131, the input terminal of the amplitude converter 132 being connected to the output terminal of the associated photoelectric sensor 131, the output terminal of the amplitude converter 132 serving as the output terminal of the photoelectric detection module 13, and the amplitude converter 132 being used to convert the liquid change trend information into liquid change trend data with a preset voltage.

[0085] In a preferred embodiment, the photoelectric detection module 13 may include two photoelectric sensors 131 and two amplitude converters 132.

[0086] In this embodiment, two photoelectric sensors 131 are respectively installed at the top and bottom of the liquid container to detect the rising and falling trends of the liquid level. The photoelectric sensors 131 employ reflective photoelectric switches with a detection distance of 5mm-30mm and a response time of less than 2ms. An amplitude converter 132 converts the switching signals from the photoelectric sensors 131 into standard voltage signals, outputting a voltage of 0V (no liquid) or 5V (liquid present).

[0087] The analog-to-digital conversion module 14 has a first input terminal connected to the output terminal of the torque detection module 11, a second input terminal connected to the output terminal of the Hall detection module 12, and an output terminal connected to the second input terminal of the processing unit 3. The analog-to-digital conversion module 14 is used to convert the torque signal into torque data and the displacement signal into displacement data.

[0088] In this embodiment, the analog-to-digital converter module 14 uses a 16-bit high-precision ADC chip with a sampling rate of 10kHz and a conversion accuracy of 0.0015%. It has eight analog input channels and can simultaneously acquire multiple signals. The analog-to-digital converter module 14 performs digital processing on the torque signal and displacement signal, and the converted data is transmitted to the processing unit 3 through the SPI interface.

[0089] In this embodiment, see Figure 3 The analog-to-digital conversion module 14 can use the high-performance analog-to-digital converter AD7606, which is an 8-channel DAS, 16-bit, 800kSPS bipolar input, synchronous sampling analog-to-digital converter (ADC). It can ensure the accuracy, real-time performance, and synchronization of the displacement information of the 7 linear Hall sensors 121 and the torque information of the 1 torque sensor 111, so as to facilitate the position analysis and judgment of the processing unit 3.

[0090] In a preferred embodiment, the measuring unit 1 comprises one torque sensor 111, seven linear Hall sensors 121, two photoelectric sensors 131, one first amplifier 112, seven second amplifiers 122, two amplitude converters 132, and an analog-to-digital converter module 14. The torque sensor 111 is a static high-precision ±0.1%FS torque sensor used to detect changes in float torque and determine changes in liquid level. The linear Hall sensors 121 are linear magnetic sensors with a sensitivity of 6.0mV / V / Gs, used to detect changes in liquid level; the change in height can be determined by detecting whether the magnetic flux through the linear magnetic sensor changes. The photoelectric sensors 131 are photoelectric sensors with a response frequency as high as 1kHz, capable of detecting the number of rotations of the motor 43 and whether the motor 43 rotates forward or backward. Each of the first amplifier 112 and seven second amplifiers 122 consists of an RC filter composed of resistors and capacitors, which can filter out noise signals in the original sensor signal. After being amplified by the high-precision instrumentation amplifier AD8821, the signal-to-noise ratio of the sensor signal can be further increased. The amplitude converter 132 is composed of MOSFETs and resistors, which mainly converts the high-voltage frequency signal output by the photoelectric sensor 131 into a 3.3V frequency signal and transmits it to the processing unit 3 for acquisition and processing. The analog-to-digital converter module 14 adopts the ADI high-performance analog-to-digital converter AD7606, which is an 8-channel DAS, 16-bit, 800kSPS bipolar input, synchronous sampling ADC. It can ensure the accuracy, real-time performance, and synchronization of the acquired signals from the seven linear Hall sensors 121 and the one torque sensor 111, and improve the system response speed, so that the processing unit 3 can quickly perform position analysis and judgment.

[0091] In this embodiment, the measuring unit 1 uses a torque sensor 111, seven linear Hall sensors 121 and two photoelectric sensors 131 to accurately determine whether the liquid level has changed and to accurately measure the liquid level height.

[0092] Example 3

[0093] See Figure 2 In this embodiment, the acquisition unit 2 may include: a temperature sensor 23, a third amplifier 21, a pressure sensor 24, and a fourth amplifier 22.

[0094] Temperature sensor 23 is used to collect the temperature signal of the liquid in the liquid container;

[0095] The third amplifier 21 has its input terminal connected to the output terminal of the temperature sensor 23 and its output terminal connected to the processing unit 3. The third amplifier 21 is used to filter and amplify the temperature signal to obtain the temperature data.

[0096] Pressure sensor 24 is used to acquire the pressure signal of the liquid in the liquid container;

[0097] The fourth amplifier 22 is connected to the output of the pressure sensor 24 and to the processing unit 3. The fourth amplifier 22 is used to filter and amplify the pressure signal to obtain the pressure data.

[0098] In this embodiment, the temperature sensor 23 is a PT100 platinum resistance thermometer with a temperature measurement range of -50℃ to 150℃ and an accuracy of ±0.1℃. The third amplifier 21 uses a three-wire connection, has adjustable gain, and an output signal range of 0V-5V. The pressure sensor 24 is a diffused silicon piezoresistive sensor with a range of 0MPa-10MPa and an accuracy of 0.2%FS. The fourth amplifier 22 is an instrumentation amplifier with a common-mode rejection ratio greater than 100dB, a gain of 200, and an output signal range of 0V-5V.

[0099] The acquisition unit 2 may also include isolation magnetic beads. Temperature signals from a 4mA-20mA temperature transmitter of the liquid container (such as an oil storage tank) are acquired via temperature sensor 23, and pressure signals from a 4mA-20mA pressure transmitter are acquired via pressure torque sensor 111. These signals are then amplified and sent to the processing unit 3. The processing unit 3 has two main functions: first, it uploads temperature and pressure data to the host computer control system via the servo level gauge transmitter; second, it performs temperature and pressure compensation on the servo level gauge's detection position based on the acquired temperature and pressure data, ensuring long-term stability and achieving a level measurement accuracy of ±0.5mm, significantly improving the measurement accuracy of the servo level gauge. Both the third amplifier 21 and the fourth amplifier 22 are composed of an operational amplifier LM258, a transient suppression diode MRB4007T3, a PTC resettable fuse, resistors, capacitors, and ferrite beads. The transient suppression diode MRB4007T3 can solve the transient impact and instability of the 4mA-20mA current signal output by the temperature sensor 23. The PTC resettable fuse can prevent the components from burning out due to excessive transient current and overheating. The LM258 operational amplifier can amplify the 4mA-20mA signal for transmission to the processing unit 3 for signal processing, ensuring the accuracy of the acquisition. At the same time, it can also play a role in signal isolation, solving the protection problem between the processing unit 3 and the acquisition unit 2.

[0100] In this embodiment, temperature sensor 23 monitors the temperature signal in real time, and processing unit 3 can dynamically correct the liquid level calculation formula according to preset medium physical property parameters (such as the coefficient of thermal expansion) to achieve temperature compensation. Pressure sensor 24 collects the pressure signal inside the liquid container, and processing unit 3 can combine parameters such as air pressure and medium characteristics (such as compressibility) of the working environment to dynamically correct the liquid level calculation formula (or model) to achieve pressure compensation. In this embodiment, temperature signal of liquid container is collected by temperature sensor 23, and pressure signal of liquid in liquid container is collected by pressure sensor 24. Temperature and pressure compensation are performed by processing unit 3. Considering that the liquid volume changes with temperature (thermal expansion and contraction), which causes the liquid level height to mismatch with the actual volume, and that the material of liquid container (such as storage tank) or measuring component (such as metal) will expand and contract with temperature, affecting the measurement reference of mechanical structure, temperature compensation is performed. Since liquid density changes with pressure (especially in high-pressure or closed containers), affecting the conversion relationship between liquid level and mass, pressure compensation is performed. This solves the problem of the impact of liquid thermal expansion and contraction and density change on measurement accuracy, improves long-term stability, and provides a guarantee for measurement accuracy.

[0101] Example 4

[0102] See Figure 2 In this embodiment, the execution unit 4 may include: an isolation module 41, a control module 42, and a motor 43.

[0103] Isolation module 41, the input terminal of which is connected to the processing unit 3, is used to isolate and enhance the control command to obtain control information;

[0104] Control module 42, the input terminal of which is connected to the output terminal of isolation module 41, is used to generate drive signals according to the control information;

[0105] Motor 43, the input terminal of which is connected to the output terminal of the control module 42, and the motor 43 performs corresponding operations according to the drive signal.

[0106] In this embodiment, the isolation module 41 uses an opto-isolator with an isolation voltage of 2500V and a transmission rate of 1Mbps, effectively preventing the transmission of interference signals and mutual influence between systems. The control module 42 uses an H-bridge drive circuit with a maximum drive current of 2A and overcurrent and overheat protection functions. The motor 43 is a stepper motor with a step angle of 1.8°, a rated voltage of 24V, a rated current of 1.5A, and a maximum torque of 1.2N·m. The motor 43 is connected to the float through a reduction mechanism, which can precisely control the position of the float, thereby achieving accurate measurement and control of the liquid level.

[0107] See Figure 9Motor 43 is a 0.9° stepper motor, and control module 42 uses the TB67S109AFTG control chip. The TB67S109AFTG control chip uses a 1 / 32 microstepping method, equivalent to 0.9 × 1 / 32 = 0.028125°. This improves the control resolution of motor 43. With a hub circumference of 400mm, the resolution can reach 0.03125mm, fully meeting the requirement of a measurement accuracy of ±0.5mm. The TB67S109AFTG control chip features low on-resistance, a high-efficiency motor 43 current control mechanism, error detection function, and built-in error detection circuit (thermal shutdown, overcurrent shutdown), fully meeting the high-precision and high-stability control requirements of the servo level gauge. Isolation module 41 uses the SN74LVC541 isolation driver chip and may also include a magnetic bead isolation circuit, resistors, and capacitors. The SN74LVC541 isolation driver chip has an 8-channel isolation buffer with tri-state output, which can ensure the stability of the control commands issued from the processing unit 3 to the control module 42 and isolate noise interference.

[0108] In this embodiment, the control module 42 uses a high-performance TB67S109AFTG control chip, which can be subdivided into 1 / 32 steps, resulting in a resolution of 0.03125mm. The chip also features error detection and a built-in error detection circuit, ensuring both accuracy and the reliability and stability of the control.

[0109] Example 5

[0110] See Figure 2 In this embodiment, the servo level transmitter may further include: a human-machine interaction module 5 and a power supply module.

[0111] The human-computer interaction module 5 is connected to the processing unit 3 and is used to receive input signals and display the temperature data, the pressure data, the float change data and the liquid change trend data.

[0112] The power supply module is connected to the measurement unit 1, the acquisition unit 2, the processing unit 3, the execution unit 4 and the human-machine interaction module 5 respectively, and is used to supply power to the measurement unit 1, the acquisition unit 2, the processing unit 3, the execution unit 4 and the human-machine interaction module 5.

[0113] In this embodiment, the human-machine interface module 5 can be composed of a button module and an LCD module, which can display liquid level height, liquid level gauge parameters, etc., and can also input and modify relevant parameters through button operation for convenient use. The power supply module consists of 24V to 15V, 24V to ±5V, and 5V to 3.3V, used to power the measurement unit 1, the acquisition unit 2, the processing unit 3, the execution unit 4, and the human-machine interface module 5.

[0114] Specifically, the human-machine interface module 5 may include a 4.3-inch color touchscreen and four function buttons, which can display parameters such as liquid level, temperature, and pressure, and support parameter settings and system configuration. The human-machine interface module 5 also has communication capabilities, supporting RS485, HART, and 4mA-20mA standard signal outputs, enabling data exchange with a host computer or DCS system, and uploading liquid level gauge information to the host computer system.

[0115] The working process of the servo level transmitter in this embodiment is as follows: the float moves up and down with the change of liquid level. The torque sensor 111 detects the change of the float's torque, the Hall sensor 121 detects the change of the float's position, the photoelectric sensor 131 detects the trend of liquid change, and the temperature sensor 23 and pressure sensor 24 detect the liquid's temperature and pressure, respectively. These signals are processed by corresponding amplifiers and converters and then transmitted to the processing unit 3. The processing unit 3 calculates the liquid level value based on the received data and generates control commands. After the control commands are processed by the isolation module 41 and the control module 42, the motor 43 is driven to run, adjusting the float position to achieve accurate measurement and control of the liquid level. At the same time, the measurement results are displayed through the human-machine interaction module 5 and can be transmitted to the upper system through the communication interface.

[0116] This servo level transmitter features high measurement accuracy, fast response speed, and strong adaptability, and can be widely used in level measurement and control in industries such as petroleum, chemical, pharmaceutical, and food.

[0117] The control method based on a servo level transmitter includes the following steps:

[0118] S1. The temperature signal of the liquid in the liquid container is collected by the temperature sensor 23, and the 4mA-20mA temperature signal is filtered and amplified by the third amplifier 21 to obtain temperature data, which is then sent to the processing unit 3; the pressure signal of the liquid in the liquid container is collected by the pressure sensor 24, and the pressure signal is filtered and amplified by the fourth amplifier 22 to obtain pressure data, which is then sent to the processing unit 3; the processing unit 3 performs temperature compensation and pressure compensation based on the temperature data and pressure data, and acquires the temperature data and pressure data;

[0119] S2. Torque information is collected by the torque sensor 111 in the measuring unit 1, and the first amplifier 112 transmits the filtered and amplified torque signal to the analog-to-digital converter module 14 in real time. The analog-to-digital converter module 14 converts the torque signal into torque data. Displacement information is collected by seven linear Hall sensors 121, and the filtered and amplified displacement signal is transmitted to the analog-to-digital converter module 14 in real time through seven second amplifiers 122. The analog-to-digital converter module 14 converts the displacement signal into displacement data and sends the torque data and displacement data to the processing unit 3. The two photoelectric sensors 131 collect the liquid change trend information, which is converted into liquid change trend data with a preset voltage (3.3V) by two amplitude converters 132 and sent to the processing unit 3. The processing unit 3 analyzes and judges the torque data, displacement data and liquid change trend data to identify whether the liquid level gauge has changed. If it has changed, the liquid level height is determined.

[0120] S3. Processing unit 3 determines whether to perform a switching operation based on the determined liquid level height. If so, it generates a control command and sends the control command to isolation module 41 to remove noise interference. The control module 42 generates a drive signal for the control PWM waveform and sends it to motor 43 to perform the switching operation.

[0121] S4. Processing unit 3 outputs 4mA-20mA current signals and pulse signals in real time through human-machine interaction module 5, and communicates with DCS central control system via RS485; at the same time, it can modify and read system parameters according to button operation information, and display the height and related parameters of servo level gauge on LCD.

[0122] Example 6

[0123] Based on Embodiment 2, the Hall detection module 12 may include different numbers of Hall sensors 121 and second amplifiers 122. For example, the Hall detection module 12 may include 5 Hall sensors 121 and 5 second amplifiers 122, or 9 Hall sensors 121 and 9 second amplifiers 122, selected according to the actual measurement range and accuracy requirements. When using 5 Hall sensors 121, they can be evenly distributed along the float's movement trajectory, with each Hall sensor 121 having a detection range of 15 mm and a spacing of 12 mm between adjacent Hall sensors 121. When using 9 Hall sensors 121, they can be evenly distributed along the float's movement trajectory, with each Hall sensor 121 having a detection range of 8 mm and a spacing of 6 mm between adjacent Hall sensors 121.

[0124] Example 7

[0125] Based on Embodiment 2, the photoelectric detection module 13 may include different numbers of photoelectric sensors 131 and amplitude converters 132. For example, the photoelectric detection module 13 may include three photoelectric sensors 131 and three amplitude converters 132, or four photoelectric sensors 131 and four amplitude converters 132, selected according to actual measurement needs. When using three photoelectric sensors 131, they can be installed at the top, middle, and bottom of the liquid container respectively for more accurate detection of liquid level change trends. When using four photoelectric sensors 131, they can be evenly distributed at different heights of the liquid container to provide more information on liquid level change trends.

[0126] It should be noted that Embodiment 1, Embodiment 2, Embodiment 3, Embodiment 4, Embodiment 5, Embodiment 6, and Embodiment 7 are all types of servo level transmitters.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A servo level transmitter, used in a liquid container, characterized in that, include: A measuring unit is used to measure dynamic data of the liquid in the liquid container, the dynamic data including float change data and liquid change trend data; The acquisition unit is used to acquire temperature and pressure data of the liquid in the liquid container; The processing unit, connected to the measurement unit and the acquisition unit respectively, is used to perform temperature compensation based on the temperature data, pressure compensation based on the pressure data, and generate control commands based on the dynamic data; An execution unit, connected to the processing unit, is used to perform corresponding operations according to the control instructions.

2. The servo level transmitter according to claim 1, characterized in that, The measurement unit includes: A torque detection module is used to measure the torque signal of the float in the liquid container; Hall effect detection module for detecting displacement signals of the float in the liquid container; A photoelectric detection module, the output of which is connected to the first input of the processing unit, is used to detect the liquid change trend data in the liquid container; An analog-to-digital converter (ADC) is provided, wherein its first input terminal is connected to the output terminal of the torque detection module, its second input terminal is connected to the output terminal of the Hall effect detection module, and its output terminal is connected to the second input terminal of the processing unit. The ADC is used to convert the torque signal into torque data and the displacement signal into displacement data.

3. The servo level transmitter according to claim 2, characterized in that, The torque detection module includes: A torque sensor is used to collect torque information of the float in the liquid container; A first amplifier is connected to the output of the torque sensor, and its output forms the output of the torque detection module. The first amplifier is used to filter and amplify the torque information to obtain the torque signal.

4. The servo level transmitter according to claim 2, characterized in that, The Hall detection module includes: At least one Hall sensor is used to collect the displacement information of the float; At least one second amplifier, the number of which is the same as the number of the Hall sensors, and each second amplifier corresponds to one Hall sensor. The input terminal of the second amplifier is connected to the output terminal of the associated Hall sensor, and the output terminal of the second amplifier serves as the output terminal of the Hall detection module. The second amplifier is used to filter and amplify the displacement information to obtain the displacement signal.

5. The servo level transmitter according to claim 4, characterized in that, The Hall detection module includes: 7 Hall sensors and 7 second amplifiers.

6. The servo level transmitter according to claim 2, characterized in that, The photoelectric detection module includes: At least one photoelectric sensor is used to detect the trend information of liquid change in the liquid container; At least one amplitude converter, the number of amplitude converters being the same as the number of photoelectric sensors, and each amplitude converter corresponding to one photoelectric sensor, the input terminal of the amplitude converter being connected to the output terminal of the associated photoelectric sensor, the output terminal of the amplitude converter serving as the output terminal of the photoelectric detection module, the amplitude converter being used to convert the liquid change trend information into liquid change trend data with a preset voltage.

7. The servo level transmitter according to claim 6, characterized in that, The photoelectric detection module includes two photoelectric sensors and two amplitude converters.

8. The servo level transmitter according to claim 1, characterized in that, The acquisition unit includes: A temperature sensor is used to collect the temperature signal of the liquid in the liquid container; A third amplifier is connected to the output of the temperature sensor, and its output is connected to the processing unit. The third amplifier is used to filter and amplify the temperature signal to obtain the temperature data. A pressure sensor is used to acquire the pressure signal of the liquid in the liquid container; A fourth amplifier is provided, the input of which is connected to the output of the pressure sensor, and the output of which is connected to the processing unit. The fourth amplifier is used to filter and amplify the pressure signal to obtain the pressure data.

9. The servo level transmitter according to claim 1, characterized in that, The execution unit includes: An isolation module, the input of which is connected to the processing unit, is used to isolate and amplify the control commands to obtain control information; A control module, the input of which is connected to the output of the isolation module, is used to generate a drive signal based on the control information; The motor has its input terminal connected to the output terminal of the control module, and the motor performs corresponding operations according to the drive signal.

10. The servo level transmitter according to claim 1, characterized in that, Also includes: A human-computer interaction module, connected to the processing unit, is used to receive input signals and display the temperature data, the pressure data, the float change data, and the liquid change trend data. The power supply module is connected to the measurement unit, the acquisition unit, the processing unit, the execution unit, and the human-machine interaction module, respectively, and is used to supply power to the measurement unit, the acquisition unit, the processing unit, the execution unit, and the human-machine interaction module.

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