Batch automatic calibration test method and system for pressure sensors

Abstract

The invention provides a batch automatic calibration test method and system for pressure sensors. The system comprises a standard pressure controller, a batch tool, an industrial personal computer, a display, a pressure sensor power supply, a high and low temperature test box and a multipath signal acquisition instrument. Wherein the industrial personal computer is respectively in communication connection with the standard pressure controller, the pressure sensor power supply and the multi-path signal acquisition instrument, and is used for controlling the working conditions of the standard pressure controller, the pressure sensor power supply and the multi-path signal acquisition instrument; the industrial personal computer receives signals of the standard pressure controller, the pressure sensor power supply and the multipath signal acquisition instrument, carries out data processing, and displays a calibration test process and a calibration test result on the display. According to the invention, unattended batch calibration test work can be automatically realized, and multi-parameter data signals of working current, bridge voltage, bridge resistance and the like can be acquired. And multi-channel parallel calibration is adopted, so that calibration test work of a plurality of sensors can be simultaneously realized. The device has the functions of pressure sensor batch calibration and batch test.

Description

Technical Field

[0001] This application relates to the field of sensor calibration technology, and in particular to a batch automated calibration test method and system for pressure sensors. Background Technology

[0002] Pressure sensors are core sensing components in industrial automation, automotive electronics, and medical equipment, and their accuracy and reliability directly affect the overall system performance. With the rapid development of the Internet of Things and smart manufacturing, the industry is placing higher demands on the mass production efficiency and consistency of pressure sensors.

[0003] Pressure sensor calibration testing is a crucial step in the sensor manufacturing process. It involves conditioning and amplifying the raw output signal of the sensor chip to obtain the standard output signal required for the product. Furthermore, data calibration at different temperatures reduces temperature errors in the sensor. Simultaneously, sensors must be tested before leaving the factory to ensure that all performance indicators meet the requirements.

[0004] Traditional testing and calibration methods rely on manual calibration, typically on a single-item basis. This is inefficient, prone to human error, and results in low equipment utilization, significantly increasing unit costs. Furthermore, the hardware limitations include insufficient compatibility with multiple models, such as mechanical interface conflicts and electrical parameter mismatch issues. Summary of the Invention

[0005] In view of this, the purpose of this application is to propose a batch automated calibration test method and system for pressure sensors, which can specifically solve the existing problems.

[0006] According to one aspect of this application, a batch automated calibration and testing system for pressure sensors is provided, comprising:

[0007] Standard pressure controller, batch tooling, industrial computer, monitor, pressure sensor power supply, high and low temperature test chamber, multi-channel signal acquisition instrument; among which,

[0008] The standard pressure controller is connected to the high and low temperature test chamber via a pneumatic pipeline;

[0009] The batch tooling is located at the bottom of the high and low temperature test chamber and is used to support one or more pressure sensors to be tested;

[0010] The power supply for the pressure sensor is connected to the pressure sensor under test via a power cable harness.

[0011] The multi-channel signal acquisition instrument is connected to the high and low temperature test chamber, batch tooling and pressure sensor under test through a signal harness;

[0012] The industrial control computer is communicatively connected to the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument, respectively, and is used to control the operating conditions of the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument.

[0013] The industrial control computer receives signals from the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument, processes the data, and displays the calibration test process and results on the display.

[0014] Furthermore, the pressure sensor is powered by a linear power supply.

[0015] Furthermore, the standard pressure controller is controlled by the industrial computer and can input nitrogen gas as a working medium into the high and low temperature test chamber to generate the required standard pressure.

[0016] Furthermore, the multi-channel signal acquisition instrument acquires the operating condition signals of the high and low temperature test chamber, batch tooling, and pressure sensor under test, and sends them to the industrial control computer.

[0017] According to another aspect of this application, this application also provides a batch automated calibration test method for pressure sensors using the above-described system, comprising:

[0018] The system is initialized and parameters are set at the beginning of the calibration phase, including the selection of calibration temperature and pressure points, and the setting of target calibration accuracy parameters; preliminary testing is performed on the sensors to be calibrated to screen out unqualified products;

[0019] Install the pressure sensor to be tested onto the batch tooling and place it in the high and low temperature test chamber. According to the pressure and temperature information to be tested set by the industrial control computer, the system automatically controls the high and low temperature test chamber to reach the target temperature. After the temperature is constant, the set pressure is applied through the standard pressure controller, and the output signal at each pressure point is collected until the sensor output under all set temperature and pressure conditions is completed.

[0020] The temperature compensation coefficient is calculated by the upper computer software compensation algorithm and burned into the data processing chip of the pressure sensor to complete the temperature compensation. The calibrated pressure sensor is judged by retesting to determine whether it meets the performance requirements and outputs a data report.

[0021] Furthermore, the host computer software compensation algorithm includes a nonlinear fitting algorithm based on the least squares method.

[0022] Furthermore, the nonlinear fitting algorithm based on the least squares method includes:

[0023] Calibration:

[0024] Given the precise input x_true, measure the sensor output y_meas to obtain the data pair (x_true, y_meas);

[0025] Using x_true as input x and y_meas as output y, fit the model y_meas=f(x_true;a,b,c) to obtain the optimal parameters a*,b*,c*.

[0026] Runtime compensation:

[0027] In actual use, the sensor outputs a measured value y_raw; and obtains the corresponding real input x_compensated.

[0028] Using the fitted model y_raw=f(x_compensated;a*,b*,c*), solve for the unknown x_compensated, such that the value of f(x_compensated;a*,b*,c*) is equal to y_raw;

[0029] Through iterative approximation, the solution x_compensated is the estimated true input value after nonlinear compensation.

[0030] Furthermore, the system automatically controls the high and low temperature test chamber to reach the target temperature based on the pressure and temperature information set by the industrial control computer, including:

[0031] The industrial control computer determines whether the pressure meets the requirements by sending a pressure query command to the standard pressure controller, and sends control commands to the standard pressure controller via serial port to achieve the pressure load required for product testing and calibration.

[0032] The industrial control computer sends commands to the high and low temperature test chamber via serial port to control the temperature.

[0033] Furthermore, the process of applying a set pressure through a standard pressure controller and collecting output signals at various pressure points until all sensor outputs under set temperature and pressure conditions are completed includes:

[0034] The industrial computer records sensor test data according to the set number of pressure cycles and uses indicator lights to determine the sensor status.

[0035] Furthermore, based on the test data, the system can automatically calculate and generate performance index parameters including sensitivity, linearity, and hysteresis, and generate reports. It also establishes a unique ID for each sensor, binds calibration data, and uploads it to the cloud database for storage.

[0036] In summary, the advantages of this application and the user experience it brings are as follows:

[0037] This application enables automated, unattended batch calibration testing, and features the ability to acquire multiple parameter data signals such as operating current, bridge voltage, and bridge resistance. Employing multi-channel parallel calibration, it can simultaneously calibrate and test multiple sensors. It also includes batch calibration and testing capabilities for pressure sensors. The system's host computer software sends relevant commands to the pressure controller and high / low temperature test chamber by setting parameters such as test temperature, test pressure, and test time, thereby obtaining the specified pressure and temperature loads. Attached Figure Description

[0038] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0039] Figure 1 A schematic diagram of the automated batch calibration and testing system for pressure sensors of this application is shown.

[0040] Figure 2 A flowchart of a test system according to an embodiment of this application is shown.

[0041] Figure 3 A schematic diagram of the calibration process according to an embodiment of this application is shown.

[0042] Figure 4 A schematic diagram of pressure and temperature control according to an embodiment of this application is shown.

[0043] Figure 5 A test interface diagram according to an embodiment of this application is shown. Detailed Implementation

[0044] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] The automated calibration and testing system designed in this application is as follows: Figure 1 As shown, it mainly consists of a standard pressure controller, batch tooling, industrial computer, display, pressure sensor power supply, high and low temperature test chamber, and multi-channel signal acquisition instrument.

[0047] The standard pressure controller is connected to the high and low temperature test chamber via a pneumatic pipeline;

[0048] The batch tooling is located at the bottom of the high and low temperature test chamber and is used to support one or more pressure sensors to be tested;

[0049] The power supply for the pressure sensor is connected to the pressure sensor under test via a power cable harness.

[0050] The multi-channel signal acquisition instrument is connected to the high and low temperature test chamber, batch tooling and pressure sensor under test through a signal harness;

[0051] The industrial control computer is communicatively connected to the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument, respectively, and is used to control the operating conditions of the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument.

[0052] The industrial control computer receives signals from the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument, processes the data, and displays the calibration test process and results on the display.

[0053] The pressure sensor is powered by a linear power supply.

[0054] The standard pressure controller, controlled by the industrial computer, is capable of inputting nitrogen gas as a working medium into the high and low temperature test chamber to generate the required standard pressure.

[0055] The multi-channel signal acquisition instrument collects the operating signals of the high and low temperature test chamber, batch tooling, and pressure sensor under test, and sends them to the industrial control computer.

[0056] The system uses pure, dry nitrogen as the working medium and is automatically controlled by a computer to achieve rapid temperature changes and generate the required standard pressure. This pressure is transmitted to the pressure sensor or transmitter being calibrated through a dedicated tooling interface. The system communicates with the device under test through a calibration device to perform calibration work, automatically records and stores calibration data, and prints the original records according to instructions.

[0057] The test system flowchart is as follows Figure 2 As shown, the pressure sensor to be tested is installed on the batch testing fixture and placed in the high and low temperature test chamber. According to the pressure and temperature information set by the industrial control computer, the system automatically controls the high and low temperature test chamber to reach the target temperature. After the temperature is constant, the set pressure is applied through the standard pressure controller, and the output signal at each pressure point is collected until the sensor output under all set temperature and pressure conditions is completed.

[0058] The calibration system flowchart is as follows Figure 3As shown, the system is initialized and parameters are set in the initial stage. This includes selecting calibration temperature and pressure points, and setting parameters such as target calibration accuracy. Preliminary testing of the sensor to be calibrated is performed to quickly screen out unqualified products, ensuring that the sensor has no obvious defects in the next stage of fine calibration. The system reaches the target temperature point according to preset information. After the temperature stabilizes, it collects the output of each preset pressure point until all temperature and pressure points are tested. The temperature compensation coefficient is calculated by the host computer software compensation algorithm and burned into the pressure sensor data processing chip to complete temperature compensation. A retest is conducted to determine whether the calibrated pressure sensor meets the performance requirements, and a data report is output. The host computer software compensation algorithm can adopt a nonlinear fitting algorithm based on the least squares method, including the following steps:

[0059] Calibration:

[0060] Given the precise input x_true (such as a standard quantity), measure the sensor output y_meas to obtain the data pair (x_true, y_meas).

[0061] Using x_true as input x and y_meas as output y, a fitted model y_meas = f(x_true; a, b, c) is obtained. The optimal parameters a*, b*, c* are then obtained. This establishes a nonlinear relationship model between the sensor input (x_true) and the output (y_meas).

[0062] Runtime compensation (inversion):

[0063] In practical use, the sensor outputs a measured value y_raw. The true input x_compensated is obtained, and a fitted model y_raw = f(x_compensated; a*, b*, c*) is used. The unknown x_compensated in this equation is solved. Because f is nonlinear, solving for x usually requires numerical root-finding methods (such as Newton's method or the bisection method). The goal is to find x_compensated such that the value of f(x_compensated; a*, b*, c*) equals y_raw. This solution is approximated iteratively. The solved x_compensated is the estimated true input value after nonlinear compensation.

[0064] Temperature and pressure control diagram as shown Figure 4 As shown, the standard pressure controller is controlled according to preset control commands based on the selected pressure control instrument. Relevant commands are sent to the pressure controller via serial port to achieve the pressure load required for product testing and calibration. In actual production, pressure query commands are mainly sent to determine whether the pressure meets the requirements. The host computer software sends preset commands to the high and low temperature test chamber via serial port to control the temperature.

[0065] Before testing, install the sensor under test (DUT) on the batch testing fixture, and close any pathways where no sensor is installed. For calibrated pressure sensors, a retest is required to verify performance and determine if requirements are met. The test interface is shown below. Figure 5 As shown, the sensor test data is recorded according to the set number of pressure cycles, and the sensor status can be judged by the indicator light.

[0066] For pressure sensors that have completed calibration testing, to facilitate subsequent data management and processing, it is necessary to record and store all relevant data generated during the entire sensor calibration testing process. This mainly includes the system's serial port configuration, sensor parameter configuration, and the raw test data and post-calibration test data. The configuration file mainly stores serial port configuration information, register configuration data, calibration methods, etc., and is generated and stored as a .ini file by the host computer software. Data reports record the device's current ID, date, pressure input range, sensor output, error rate, etc., and are saved as generated Excel files.

[0067] The invention has three main innovative aspects:

[0068] 1. Multi-parameter automated batch calibration and testing equipment: The system, through the design of a matrix-type pneumatic / electrical switching device combined with an intelligent circuit controller, can support the synchronous connection of N×M sensors (N≥5, M≥5); multiple stations can simultaneously perform measurement and calibration, and the software system displays the qualification status of the tested sensors in real time through status indicator lights. It can perform multi-parameter sensor signal testing such as operating current, bridge voltage, output signal, and bridge resistance.

[0069] 2. Three-Level Calibration Process: A three-level calibration process is adopted. In the preliminary testing stage, pressures of 20%, 50%, and 80% of the measurement range are applied to the pressure sensor respectively. Defective products are quickly screened based on preset parameters. In the refined calibration stage, multiple equally spaced pressure points are selected within the preset full measurement range to collect the pressure sensor output signal. In the temperature compensation stage, preset pressure point signals are collected at each preset temperature point. Based on the output data under different temperatures and pressures, the temperature compensation coefficient is calculated by the host computer software algorithm, thereby achieving calibration compensation of the pressure sensor.

[0070] 3. Intelligent Data Processing: The system's host computer software integrates multiple temperature compensation algorithms, including a nonlinear fitting algorithm based on the least squares method. Based on test data, the system can automatically calculate and generate performance parameters such as sensitivity, linearity, and hysteresis, and generate reports. Furthermore, it establishes a unique ID for each sensor, binds calibration data, and uploads it to a cloud database for storage.

[0071] It should be noted that:

[0072] The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, this application is not directed to any particular programming language. It should be understood that the content of this application described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of this application.

[0073] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0074] Similarly, it should be understood that, in order to simplify this application and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of this application, various features of this application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0075] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0076] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0077] The various component embodiments of this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components in the virtual machine creation system according to the embodiments of this application. This application can also be implemented as a device or system program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0078] It should be noted that the above embodiments are illustrative of this application and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several systems, several of these systems may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0079] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A batch automated calibration and testing system for pressure sensors, characterized in that, include: Standard pressure controller, batch tooling, industrial computer, monitor, pressure sensor power supply, high and low temperature test chamber, multi-channel signal acquisition instrument; among which, The standard pressure controller is connected to the high and low temperature test chamber via a pneumatic pipeline; The batch tooling is located at the bottom of the high and low temperature test chamber and is used to support one or more pressure sensors to be tested; The power supply for the pressure sensor is connected to the pressure sensor under test via a power cable harness. The multi-channel signal acquisition instrument is connected to the high and low temperature test chamber, batch tooling and pressure sensor under test through a signal harness; The industrial control computer is communicatively connected to the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument, respectively, and is used to control the operating conditions of the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument. The industrial control computer receives signals from the standard pressure controller, the pressure sensor power supply, and the multi-channel signal acquisition instrument, processes the data, and displays the calibration test process and results on the display.

2. The batch automated calibration and testing system for pressure sensors according to claim 1, characterized in that, The pressure sensor is powered by a linear power supply.

3. The batch automated calibration and testing system for pressure sensors according to claim 1, characterized in that, The standard pressure controller, controlled by the industrial computer, is capable of inputting nitrogen gas as a working medium into the high and low temperature test chamber to generate the required standard pressure.

4. The batch automated calibration and testing system for pressure sensors according to claim 1, characterized in that, The multi-channel signal acquisition instrument collects the operating signals of the high and low temperature test chamber, batch tooling, and pressure sensor under test, and sends them to the industrial control computer.

5. A batch automated calibration test method for pressure sensors using the system of any one of claims 1-4, characterized in that, include: The system is initialized and parameters are set at the beginning of the calibration phase, including the selection of calibration temperature and pressure points, and the setting of target calibration accuracy parameters; preliminary testing is performed on the sensors to be calibrated to screen out unqualified products; Install the pressure sensor to be tested onto the batch tooling and place it in the high and low temperature test chamber. According to the pressure and temperature information to be tested set by the industrial control computer, the system automatically controls the high and low temperature test chamber to reach the target temperature. After the temperature is constant, the set pressure is applied through the standard pressure controller, and the output signal at each pressure point is collected until the sensor output under all set temperature and pressure conditions is completed. The temperature compensation coefficient is calculated by the upper computer software compensation algorithm and burned into the data processing chip of the pressure sensor to complete the temperature compensation. The calibrated pressure sensor is judged by retesting to determine whether it meets the performance requirements and outputs a data report.

6. The batch automated calibration test method for pressure sensors according to claim 5, characterized in that, The host computer software compensation algorithm includes a nonlinear fitting algorithm based on the least squares method.

7. The batch automated calibration test method for pressure sensors according to claim 6, characterized in that, The nonlinear fitting algorithm based on the least squares method includes: Calibration: Given the precise input x_true, measure the sensor output y_meas to obtain the data pair (x_true, y_meas); Using x_true as input x and y_meas as output y, fit the model y_meas=f(x_true;a,b,c) to obtain the optimal parameters a*,b*,c*. Runtime compensation: In actual use, the sensor outputs a measured value y_raw; and obtains the corresponding real input x_compensated. Using the fitted model y_raw=f(x_compensated;a*,b*,c*), solve for the unknown x_compensated, such that the value of f(x_compensated;a*,b*,c*) is equal to y_raw; Through iterative approximation, the solution x_compensated is the estimated true input value after nonlinear compensation.

8. The batch automated calibration test method for pressure sensors according to claim 5, characterized in that, The system automatically controls the high and low temperature test chamber to reach the target temperature based on the pressure and temperature information set by the industrial control computer, including: The industrial control computer determines whether the pressure meets the requirements by sending a pressure query command to the standard pressure controller, and sends control commands to the standard pressure controller via serial port to achieve the pressure load required for product testing and calibration. The industrial control computer sends commands to the high and low temperature test chamber via serial port to control the temperature.

9. The batch automated calibration test method for pressure sensors according to claim 5, characterized in that, The process involves applying a set pressure using a standard pressure controller, collecting output signals at various pressure points, and continuing until all sensor outputs under set temperature and pressure conditions are completed. This includes: The industrial computer records sensor test data according to the set number of pressure cycles and uses indicator lights to determine the sensor status.

10. A batch automated calibration test method for pressure sensors according to claim 5, characterized in that, Based on the test data, the system can automatically calculate and generate performance index parameters including sensitivity, linearity, and hysteresis, and generate reports. It also establishes a unique ID for each sensor, binds calibration data, and uploads it to the cloud database for storage.

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