Dynamic calibration method and device for pressure sensor

Abstract

The invention provides a pressure sensor dynamic calibration method and device, and the method comprises the steps: 1) enabling a to-be-tested pressure sensor to be installed in a pressure pipeline on a test frame, and placing a standard pressure sensor in the pressure pipeline, and enabling the standard pressure sensor to be used for monitoring the actual pressure in the pressure pipeline in real time; 2) placing the test frame in a high-low temperature test box, connecting the test frame with a pressure reference, setting the initial temperature and the final temperature of the high-low temperature test box according to the working upper and lower limit temperatures of the to-be-tested pressure sensor, and setting the heat preservation time of the upper and lower limit temperature points; 3) setting a preset pressure test point and the temperature change rate and cycle index of the high-low temperature test box, and starting the high-low temperature test box; (4) pressure is given to the pressure sensors to be tested one by one through the pressure reference, staying is conducted for 10 s at each preset pressure testing point, the real-time pressure is recorded through the standard pressure sensor in the testing pipeline, meanwhile, output signals of the pressure sensors to be tested under the current pressure are collected, and the pressure values and the output signals are recorded one by one; 5) executing the step 4) again until the circulation of the high and low temperature test box is finished; and 6) summarizing all the data, performing data curved surface fitting according to a high-order formula to obtain sensor fitting parameters, and completing dynamic calibration. The calibration time in the production process of the silicon resonance pressure sensor can be effectively shortened, and the calibration efficiency of the sensor is improved. The method can also be applied to other pressure sensors.

Description

Technical Field

[0001] The invention belongs to the technical field of sensors, and in particular relates to a pressure sensor dynamic calibration method and device. Background Art

[0002] Silicon resonant pressure sensor is one of the most accurate pressure sensors currently, with a comprehensive accuracy of better than 0.02% FS. Silicon resonant pressure sensor uses a composite measurement method of resonator and pressure sensitive diaphragm. When pressure acts on the diaphragm, the frequency of the resonator fixed at both ends to the diaphragm changes, which is used to characterize the pressure.

[0003] The silicon resonant pressure sensor uses a resonator as a sensitive element, with a pressure signal input and a frequency signal output. It is also sensitive to temperature signals. Therefore, in order to eliminate the influence of temperature, a temperature-sensitive device is designed inside the sensor to measure the temperature. The sensor is calibrated over the full temperature and pressure range, and the pressure and temperature signals obtained through calibration are fitted according to a certain algorithm to form a pressure-temperature function relationship, thereby deriving the corresponding relationship between the output frequency signal and the input pressure signal.

[0004] The silicon resonant pressure sensor is calibrated using a static calibration method. The calibration model is shown in Figure 1 . Specifically: within the operating temperature range and working pressure range of the sensor, select N (generally 10 to 15, including upper and lower temperature limits) temperature calibration points and M pressure points (generally 11 to 15, including upper and lower pressure limits), and perform 3 pressure cycle tests at each temperature point under constant temperature conditions. According to the selected temperature points, complete the pressure cycle calibration under N selected temperature constant temperature conditions from high to low or from low to high, obtain (N×M×6) groups of calibration data, normalize the data, average the data, and fit the data surface to obtain the eigenfunction relationship between the sensor calibration pressure, temperature, and output signal. Figure 1 Where T1~Tn are calibration temperature points, T1 is the lower temperature limit, Tn is the upper temperature limit; t1~tn is the time required for the calibration pressure cycle at a single temperature point.

[0005] In this method, a single temperature and pressure calibration usually takes 5 to 6 hours, and it takes 55 to 90 hours to complete one calibration. The calibration time is long and the efficiency is low. Summary of the invention

[0006] The present invention provides a pressure sensor dynamic calibration method and device, which solves the problem of long single temperature pressure calibration time and low efficiency in the existing method.

[0007] The present invention provides a pressure sensor dynamic calibration method, comprising:

[0008] 1) Install the pressure sensor to be tested in the pressure pipeline on the test stand, and place a standard pressure sensor in the pressure pipeline to monitor the actual pressure in the pressure pipeline in real time;

[0009] 2) Place the test frame in a high and low temperature test chamber, connect the test frame to the pressure reference, set the starting temperature and ending temperature of the high and low temperature test chamber according to the upper and lower working temperature limits of the pressure sensor to be tested, and set the insulation time of the upper and lower temperature points;

[0010] 3) Set the preset pressure test point, the temperature change rate and cycle number of the high and low temperature test chamber, and start the high and low temperature test chamber;

[0011] 4) Give pressure to the pressure sensor to be tested one by one through the pressure reference, stay at each preset pressure test point for 10 seconds, record the real-time pressure through the standard pressure sensor in the test pipeline, and collect the output signal of the pressure sensor to be tested under the current pressure, and record the above pressure values ​​and output signals one by one;

[0012] 5) Execute step 4) again until the cycle of the high and low temperature test chamber is completed;

[0013] 6) Summarize all the above data, perform data surface fitting according to the high-order formula, obtain the sensor fitting parameters, and complete the dynamic calibration.

[0014] Optionally, the test frame pipeline adopts a symmetrical design, and multiple sensors to be tested are symmetrically arranged in the test frame pipeline.

[0015] Optionally, a standard pressure sensor is placed in the centrally located test stand pipe.

[0016] Optionally, the starting temperature and the ending temperature of the high and low temperature test chamber are 2 to 5°C wider than the upper and lower working temperature limits of the sensor.

[0017] Optionally, set the holding time for the upper and lower temperature limit points according to the temperature response capability of the sensor.

[0018] Optionally, the insulation time is 0.5h to 1h.

[0019] Optionally, the temperature change rate of the high and low temperature test chamber is no more than 3°C / min, and the number of cycles is 1 to 3 times.

[0020] A second aspect of the present invention provides a pressure sensor dynamic calibration device for executing the method as described in any one of the first aspects.

[0021] The present invention provides a pressure sensor dynamic calibration method and device, which can effectively shorten the calibration time in the production process of silicon resonant pressure sensors and improve the calibration efficiency of sensors. The method can also be applied to other pressure sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Calibrate the existing model;

[0023] Figure 2 A schematic diagram of a dynamic calibration method for a pressure sensor provided by the present invention;

[0024] Figure 3 A schematic diagram of a scenario of the pressure sensor dynamic calibration method provided by the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention.

[0026] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is by no means limited to any specific settings and methods proposed below, but covers any improvements, replacements and modifications of structures, methods, devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity in the present invention.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0029] like Figure 2 and 3 As shown, the present invention is implemented by the following technical solution:

[0030] Temperature dynamic calibration is adopted, and the calibration model is shown in Figure 2Under the premise of ensuring the final performance accuracy of the sensor, a dynamic calibration method for silicon resonant pressure sensor is studied. The upper and lower working temperature limits of the sensor are used as the starting temperature and the ending temperature (widened by 2-5°C when necessary). The sensor is installed in the test pipeline and placed in a high and low temperature test chamber. A standard pressure sensor is set in the test pipeline to monitor the actual pressure in the pressure pipeline in real time. The temperature in the high and low temperature test chamber is set to change at a rate of no more than 3°C / min. The preset pressure point is given by the pressure reference. The signal output of the sensor at each pressure test point is measured, and the corresponding relationship between the actual pressure felt by the sensor at full temperature and the output signal can be obtained. The characteristic surface of the sensor can be obtained by data fitting, and the sensor data calibration is completed. Figure 2 In the figure, T1 is the lower limit of the sensor operating temperature, and Tn is the upper limit of the sensor operating temperature.

[0031] The specific implementation process of the pressure sensor dynamic calibration method provided by the present invention is as follows:

[0032] 1) Install the sensor on the test stand. The test stand pipeline adopts a symmetrical design. A standard pressure sensor is placed at the relative center of the test pipeline to monitor the actual pressure in the pressure pipeline in real time;

[0033] 2) Place the sensor and pipeline in a high and low temperature test chamber. The pipeline connecting the test frame and the pressure reference should be as short as possible. Set the starting temperature and ending temperature of the high and low temperature test chamber according to the upper and lower working temperature limits of the sensor (widen by 2 to 5°C when necessary). Set the insulation time of the upper and lower temperature points according to the temperature response capability of the sensor, generally set to 0.5h to 1h; the temperature change rate should not exceed 3°C / min, and the number of cycles should generally be set to 1 to 3 times;

[0034] 3) Set the preset pressure test point and start the high and low temperature test chamber;

[0035] 4) Give the sensor a given pressure one by one through the pressure reference, stay at each pressure test point for 10 seconds, record the real-time pressure through the standard pressure sensor in the test pipeline, and collect the sensor output signal under the current pressure at the same time, and record the above pressure values ​​and output signals one by one;

[0036] 5) Repeat step 4) until the temperature cycle is completed;

[0037] 6) Summarize all the above data, perform data surface fitting according to the high-order formula, and obtain the sensor fitting parameters.

[0038] It has been verified that the calibration time of the silicon resonant pressure sensor is shortened to 1 / 3 to 1 / 4 of the conventional calibration time by using this dynamic calibration method, which greatly shortens the calibration time of the sensor. The characteristic function relationship between the sensor calibration pressure, temperature and output signal obtained by fitting the data obtained by this calibration method is equivalent to the characteristic function relationship between the sensor calibration pressure, temperature and output signal obtained by fitting the data obtained by the traditional static calibration method. The sensor accuracy meets 0.02% FS.

[0039] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A pressure sensor dynamic calibration method, characterized in that: include: 1) Install the pressure sensor to be tested in the pressure pipeline on the test stand, and place a standard pressure sensor in the pressure pipeline to monitor the actual pressure in the pressure pipeline in real time; 2) Place the test frame in a high and low temperature test chamber, connect the test frame to the pressure reference, set the starting temperature and ending temperature of the high and low temperature test chamber according to the upper and lower working temperature limits of the pressure sensor to be tested, and set the insulation time of the upper and lower temperature points; 3) Set the preset pressure test point, the temperature change rate and cycle number of the high and low temperature test chamber, and start the high and low temperature test chamber; 4) Give pressure to the pressure sensor to be tested one by one through the pressure reference, stay at each preset pressure test point for 10 seconds, record the real-time pressure through the standard pressure sensor in the test pipeline, and collect the output signal of the pressure sensor to be tested under the current pressure, and record the above pressure values ​​and output signals one by one; 5) Execute step 4) again until the cycle of the high and low temperature test chamber is completed; 6) Summarize all the above data, perform data surface fitting according to the high-order formula, obtain the sensor fitting parameters, and complete the dynamic calibration.

2. The pressure sensor dynamic calibration method according to claim 1, characterized in that: The test frame pipeline adopts a symmetrical design, and multiple sensors under test are symmetrically arranged in the test frame pipeline.

3. The pressure sensor dynamic calibration method according to claim 2, characterized in that: A standard pressure sensor is placed in the centrally located test stand pipe.

4. The pressure sensor dynamic calibration method according to claim 1, characterized in that: The starting and ending temperatures of the high and low temperature test chamber are 2 to 5°C wider than the upper and lower working temperatures of the sensor.

5. The pressure sensor dynamic calibration method according to claim 1, characterized in that: Set the holding time for the upper and lower temperature limits according to the temperature response capability of the sensor.

6. The pressure sensor dynamic calibration method according to claim 5, characterized in that: The insulation time is 0.5h~1h.

7. The pressure sensor dynamic calibration method according to claim 1, characterized in that: The temperature change rate of the high and low temperature test chamber is not greater than 3°C / min, and the number of cycles is 1 to 3 times.

8. A pressure sensor dynamic calibration device, characterized in that: Used to perform the method according to any one of claims 1 to 7.

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