Conductivity sensor pressure compensation test system and method

Abstract

The invention discloses a conductivity sensor pressure compensation test system and method, and relates to the field of sensor test. The conductivity sensor testing device comprises a pressure-resistant shell, a temperature sensor and an acquisition module, the standard pressure gauge is used for pressurizing the conductivity sensor and recording a standard pressure value; the seawater thermostatic bath is used for manufacturing a standard constant-temperature environment for the conductivity sensor; and the standard platinum resistance thermometer is placed in the seawater thermostatic bath and is used for measuring a standard temperature value. During testing, a corresponding standard conductivity value can be calculated according to the standard pressure value and the standard temperature value recorded at each temperature control point and the salinity value of standard seawater; the conductivity measurement values corresponding to all the temperature control points, the standard conductivity values and the standard pressure values are fitted, and the pressure compensation coefficient can be calculated. During measurement, the conductivity measurement value of the conductivity sensor is corrected by using the pressure compensation coefficient, so that the conductivity measurement precision can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of sensor testing, and in particular to a conductivity sensor pressure compensation testing system and method. Background Art

[0002] The hadal trenches below 6,500 meters have extremely rich and special scientific phenomena. Conducting hadal scientific research is of great significance for revealing scientific issues such as the movement of the earth's continental plates, the origin of life, and tsunami warning. Seawater temperature, salinity, and depth characterize the physical and electromagnetic properties of seawater and are the most basic observation elements in hadal physical oceanography. Conducting research on the full-sea-depth, high-precision, rapid-response conductivity temperature and depth (CTD) measurement technology for submersible platforms will not only provide the necessary environmental information for underwater maneuvers and safe operations of submersible platforms, but also the high-precision temperature, salinity, and density distribution information obtained from the full-sea-depth operating area from the sea surface to 11,000 meters will also provide key data for conducting research on material exchange and biological characteristics of hadal edge water, revealing deep-sea turbulent mixing, and internal ocean circulation.

[0003] Since seawater temperature and salinity are relatively stable at depths below 2,000 meters, the measurement accuracy requirements are relatively high. Generally, the temperature and salinity indicators are required to be 0.002°C and 0.005PSU, and the conductivity measurement converted to less than 0.003mS / cm. When using a conductivity sensor for deep and high-precision CTD, the structural deformation caused by the microstructure change of the conductivity sensor material under high pressure environment cannot be ignored. However, there is no method for pressure compensation or correction of conductivity sensors in the existing industry standards, resulting in inaccurate deep-sea conductivity measurements. Summary of the invention

[0004] In view of this, the present application provides a conductivity sensor pressure compensation test system and method, so as to obtain a pressure compensation coefficient to correct the conductivity sensor measurement value and improve the conductivity measurement accuracy.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] On the one hand, the present application provides a conductivity sensor pressure compensation test system, including: a conductivity sensor test device, a host computer, a standard pressure gauge, a seawater constant temperature bath, a standard platinum resistance thermometer and a temperature measuring bridge; The conductivity sensor testing device comprises a pressure-resistant shell, a temperature sensor and a collection module; the pressure-resistant shell comprises a pressure-resistant cylinder, a pressure-resistant flange and a sealing cylinder; one side of the pressure-resistant flange is connected to the pressure-resistant cylinder, and the other side of the pressure-resistant flange is connected to the sealing cylinder; one end of the pressure-resistant cylinder is an externally threaded pressure pipe interface for connecting the pressure pipe of a standard pressure gauge; the other end of the pressure-resistant cylinder is an internally threaded interface connected to one side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are both located inside the pressure-resistant cylinder; the collection module is located inside the sealing cylinder; the temperature sensor and the conductivity sensor are installed on one side of the pressure-resistant flange, and the collection module is installed on the other side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are electrically connected to the collection module; the collection module is also connected to the host computer for communication; The standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value; The seawater constant temperature tank is used to create a standard constant temperature environment for the conductivity sensor; The standard platinum resistance thermometer is placed in a seawater constant temperature bath to measure the standard temperature value; The temperature measuring bridge is connected to a standard platinum resistance thermometer and is used to read and display the standard temperature value measured by the standard platinum resistance thermometer.

[0007] Optionally, the temperature control fluctuation and uniformity of the seawater thermostatic bath are better than 0.003°C.

[0008] Optionally, the temperature sensor has the same accuracy as a standard platinum resistance thermometer.

[0009] Optionally, the pressure-resistant shell is made of stainless steel or titanium.

[0010] On the other hand, the present application provides a conductivity sensor pressure compensation test method, based on the conductivity sensor pressure compensation test system; the conductivity sensor pressure compensation test method comprises: During the test, fill the conductivity sensor with standard seawater of known salinity and install the pressure-resistant cylinder, then place the conductivity sensor test device in a seawater constant temperature bath; Different temperature control points and pressure combinations are selected in combination with changes in ocean temperature and salinity. The temperature is controlled by a seawater constant temperature tank and the pressure is increased by a standard pressure gauge. When the conductivity measurement value of the conductivity sensor changes non-monotonically within the preset time and the temperature sensor indication is consistent with the standard temperature value displayed by the temperature measuring bridge, the conductivity measurement value, standard pressure value and standard temperature value of the current temperature control point are recorded, and then the temperature and pressure values ​​are changed to perform the next temperature control point test; Calculate the corresponding standard conductivity value according to the standard pressure value, standard temperature value and standard seawater salinity value recorded at each temperature control point; The conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points are fitted to calculate the pressure compensation coefficient; During measurement, the pressure compensation coefficient is used to correct the conductivity measurement value of the conductivity sensor.

[0011] Optionally, the step of filling the conductivity sensor with standard seawater of known salinity and installing a pressure-resistant cylinder specifically includes: Fill the conductivity sensor with standard seawater of known salinity through a self-priming pump, then seal both ends of the conductivity sensor with cut-off clamps and install it on a pressure-resistant flange; After clearing the water in the pressure-resistant cylinder, put it on the pressure-resistant flange and tighten it to reinforce it.

[0012] Optionally, the selecting of different temperature control points and pressure combinations in combination with changes in ocean temperature and salinity specifically includes: In combination with changes in ocean temperature and salinity, (20℃, 1MPa), (9℃, 5MPa), (4.5℃, 10MPa), (2.5℃, 20MPa), (2℃, 50MPa) and (1.5℃, 70MPa) are selected as different temperature control points and pressure combinations.

[0013] Optionally, the preset time is 10 minutes.

[0014] Optionally, fitting the conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points to calculate the pressure compensation coefficient specifically includes: Based on the formula Fit the conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points to calculate the pressure compensation coefficient ;in For the The conductivity measurement value corresponding to each temperature control point; For the The standard conductivity value corresponding to each temperature control point; For the The standard pressure value corresponding to each temperature control point.

[0015] Optionally, during the measurement, the conductivity measurement value of the conductivity sensor is corrected using a pressure compensation coefficient, specifically including: When measuring, based on the formula Conductivity measurements for conductivity sensors Make corrections to obtain conductivity correction values Output is performed; is the corresponding pressure measurement value.

[0016] According to the specific embodiments provided in this application, this application discloses the following technical effects: In a conductivity sensor pressure compensation test system and method provided by the present application, the conductivity sensor test device includes a pressure-resistant shell, a temperature sensor and an acquisition module; a standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value; a seawater constant temperature bath is used to create a standard constant temperature environment for the conductivity sensor; a standard platinum resistance thermometer is placed in the seawater constant temperature bath to measure the standard temperature value. During the test, the corresponding standard conductivity value can be calculated according to the standard pressure value and standard temperature value recorded at each temperature control point and the salinity value of the standard seawater; the conductivity measurement value, the standard conductivity value and the standard pressure value corresponding to all temperature control points are fitted to calculate the pressure compensation coefficient. During measurement, the conductivity measurement value of the conductivity sensor is corrected using the pressure compensation coefficient, which can improve the conductivity, especially the deep-sea conductivity measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the conductivity sensor pressure compensation test system; Figure 2 It is a structural schematic diagram of a conductivity sensor testing device; Figure 3 Schematic diagram of filling the conductivity sensor with standard seawater of known salinity; Figure 4 It is a schematic diagram of a fitting curve of conductivity measurement value, standard conductivity value and standard pressure value in a certain embodiment. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] The purpose of this application is to propose a conductivity sensor pressure compensation test system and method, so as to obtain a pressure compensation coefficient to correct the conductivity sensor measurement value and improve the conductivity measurement accuracy.

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] like Figure 1 As shown, in an exemplary embodiment, the present application provides a conductivity sensor pressure compensation test system, including: a conductivity sensor test device 1, a host computer 2, a standard pressure gauge 3, a seawater constant temperature bath 4, a standard platinum resistance thermometer 5 and a temperature measuring bridge 6.

[0023] like Figure 2 As shown, in an exemplary embodiment, the conductivity sensor testing device 1 includes a pressure-resistant housing, a temperature sensor 101 and a collection module 102. The pressure-resistant housing serves as a loading container for the conductivity sensor 100, the temperature sensor 101 and the collection module 102 to be tested, and the specific structure includes a pressure-resistant cylinder 103, a pressure-resistant flange 104 and a sealing cylinder 105. In an exemplary embodiment, the conductivity sensor 100 to be tested may be a three-electrode conductivity sensor.

[0024] Among them, one side of the pressure-resistant flange 104 is connected to the pressure-resistant cylinder 103, and the other side of the pressure-resistant flange 104 is connected to the sealing cylinder 105. Specifically, one end of the pressure-resistant cylinder 103 is an externally threaded pressure pipe interface 106, which is used to connect the pressure pipe 301 of the standard pressure gauge 3. The other end of the pressure-resistant cylinder 103 is an internal thread, which is connected to one side of the pressure-resistant flange 104. The temperature sensor 101 and the conductivity sensor 100 are both located inside the pressure-resistant cylinder 103. The acquisition module 102 is located inside the sealing cylinder 105. During the test, the interior of the pressure-resistant cylinder 103 is filled with standard seawater of known salinity, and then connected to the standard pressure gauge 3 through the pressure pipe 301 for pressurization.

[0025] In an exemplary embodiment, the pressure-resistant housing may be in a cylindrical shape and made of stainless steel or titanium.

[0026] Specifically, the temperature sensor and the conductivity sensor 100 are installed on one side of the pressure-resistant flange 104, and the acquisition module 102 is installed on the other side of the pressure-resistant flange 104. The temperature sensor 101 and the conductivity sensor 100 are electrically connected to the acquisition module 102. The acquisition module 102 is also connected to the host computer 2 for communication. The sealing cylinder 105 is used as a waterproof shell of the acquisition module 102, and a through hole for the cable to pass through is provided thereon, and the connection between the cable and the sealing cylinder 105 needs to be sealed. The acquisition module 102 communicates with the host computer 2 via the cable. During the test, the acquisition module 102 simultaneously collects the original signals of the conductivity sensor 100 and the temperature sensor 101, that is, the analog signals of the conductivity measurement value and the temperature measurement value, and converts them into digital signals and sends them to the host computer 2. In an exemplary embodiment, the acquisition module 102 can be screwed on the other side of the pressure-resistant flange 104, and the collected conductivity measurement value and temperature measurement value are directly displayed in the host computer 2 in the form of digital signals.

[0027] During the test, the temperature sensor 101 is installed side by side with the conductivity sensor 100 and connected to the acquisition module 102, and the pressure tube 103 is filled with water. The temperature sensor 101 is used to measure the water temperature inside the pressure shell, and the temperature measurement value is sent to the host computer 2 via the acquisition module 102.

[0028] The standard pressure gauge 3 is used to pressurize the conductivity sensor 100 and record the standard pressure value. The standard pressure gauge 3 is located outside the seawater thermostatic tank 4, connected to the pressure pipe interface 106 of the conductivity sensor testing device 1 through the pressure pipe 301, and then pressurized. The standard pressure value is the standard pressure gauge display value. The pressure pipe 301 can be a stainless steel pipe.

[0029] The seawater constant temperature tank 4 is used to create a standard constant temperature environment for the conductivity sensor 100 being tested. The seawater constant temperature tank 4 is not of a specific type, and can be any type that meets the temperature control requirements. During the test, the conductivity sensor 100 is first placed in the conductivity sensor test device 1, and then the conductivity sensor test device 1 is completely immersed in the standard seawater in the seawater constant temperature tank 4 to balance the temperature so that the temperature inside and outside the conductivity sensor test device 1 is consistent.

[0030] In an exemplary embodiment, the seawater constant temperature bath 4 may be a high-precision constant temperature water bath, and its temperature control fluctuation and uniformity are better than 0.003°C, preferably 0.001°C, and more preferably 0.0005°C.

[0031] The standard platinum resistance thermometer 5 is placed in the seawater constant temperature tank 4 to measure the standard temperature value of the standard seawater in the seawater constant temperature tank 4 .

[0032] The temperature measuring bridge 6 is connected to the standard platinum resistance thermometer 5 and is used to read and display the standard temperature value measured by the standard platinum resistance thermometer 5 for the convenience of experimenters to record.

[0033] The temperature sensor 100 built into the conductivity sensor test device 1 is set to compare with the standard platinum resistance thermometer 5 placed in the seawater constant temperature bath 4 to monitor whether the temperature inside and outside the pressure-resistant shell is consistent. Therefore, the temperature sensor 100 needs to have the same accuracy as the standard platinum resistance thermometer 5.

[0034] based on Figure 1 The conductivity sensor pressure compensation test system shown in the figure, the present application also provides a conductivity sensor pressure compensation test method. The conductivity sensor pressure compensation test method includes the following steps S1 to S6.

[0035] S1: During the test, the conductivity sensor 100 is filled with standard seawater of known salinity and the pressure-resistant cylinder 103 is installed, and then the conductivity sensor testing device 1 is placed in a seawater constant temperature bath 4 .

[0036] like Figure 3 As shown, the conductivity sensor 100 can be filled with standard seawater of known salinity through a self-priming pump, and then the two ends of the conductivity sensor 100 are sealed with a cut-off clamp 107, and then installed on the pressure-resistant flange 104. Specifically, the conductivity sensor 100 is mechanically connected to the pressure-resistant flange 104 through a connecting seat, wherein a wire is provided inside the connecting seat, and the wire passes through a through hole provided on the pressure-resistant flange 104 to be electrically connected to the acquisition module 102. Similarly, the wire of the temperature sensor 101 can also pass through a through hole provided on the pressure-resistant flange 104 to be electrically connected to the acquisition module 102. The connection between the wire and the pressure-resistant flange 104 needs to be sealed.

[0037] After the pressure tube 103 is filled with clean water, the pressure tube 103 is slowly put on the pressure flange 104 and tightened to reinforce. Then, the externally threaded pressure pipe interface 106 of the pressure tube 103 is connected to the standard pressure gauge 3 through the pressure pipe 301, and the conductivity sensor test device 1 is placed in the seawater constant temperature tank 4. The seawater constant temperature tank 4 is also filled with standard seawater of known salinity.

[0038] S2: Select different temperature control points and pressure combinations in combination with changes in ocean temperature and salinity, control the temperature through a seawater constant temperature tank 4, and apply pressure through a standard pressure gauge 3.

[0039] Different combinations of temperature control points and pressures are selected in combination with changes in ocean temperature and salinity. For reference, the combinations of temperature control points and pressures such as (20°C, 1MPa), (9°C, 5MPa), (4.5°C, 10MPa), (2.5°C, 20MPa), (2°C, 50MPa), and (1.5°C, 70MPa) can be used. Then, the temperature and pressure are controlled according to different combinations of temperature control points and pressures.

[0040] Since the temperature inside the pressure-resistant shell will rise after pressurization, the internal pressure will drop after temperature control and heat dissipation. Therefore, the pressure can be increased in advance to 102% of the reference pressure value in the above temperature control point and pressure combination for pressure maintenance.

[0041] S3: When the conductivity measurement value uploaded by the host computer 2 display acquisition module 102 changes non-monotonically within the preset time (usually 10 minutes) and the temperature sensor indication is consistent with the temperature measuring bridge indication, the conductivity measurement value, standard pressure value and standard temperature value of the current temperature control point are recorded, and then the temperature and pressure values ​​are changed to perform the next temperature control point test.

[0042] The temperature sensor indication refers to the temperature measurement value of the temperature sensor 101. The temperature bridge indication refers to the standard temperature value displayed by the temperature bridge 6. The salinity value of standard seawater with known salinity can also be called the standard salinity value. The corresponding conductivity measurement value, standard pressure value and standard temperature value are recorded as , and .

[0043] S4: Calculate the corresponding standard conductivity value according to the standard pressure value and standard temperature value recorded at each temperature control point and the salinity value of the standard seawater.

[0044] Based on the standard pressure value recorded at each temperature control point , Standard temperature value The salinity value of the injected standard seawater can be calculated according to the PSS-78 salt standard formula to obtain the standard conductivity value corresponding to each temperature control point. .

[0045] S5: Fit the conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points to calculate the pressure compensation coefficient.

[0046] Refer to formulas (1) and (2) to fit the conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points to calculate the pressure compensation coefficient .

[0047] (1) (2) in For the The conductivity measurement value corresponding to each temperature control point; For the The standard conductivity value corresponding to each temperature control point; For the The standard pressure value corresponding to each temperature control point.

[0048] When fitting, As an independent variable, As the dependent variable, a linear function is used For all Value and The value is fitted, that is, the fitting is entered , Perform fitting and obtain the slope The value is the pressure compensation coefficient The value of is usually a fixed value.

[0049] S6: During measurement, the conductivity measurement value of the conductivity sensor 100 is corrected using the pressure compensation coefficient.

[0050] During measurement, the conductivity measurement value measured in real time by the conductivity sensor 100 is calculated based on formula (3): Make corrections to obtain conductivity correction values As measured output.

[0051] (3) in is the pressure measurement value corresponding to the current measurement. The measured conductivity value (i.e., conductivity measurement value) is corrected by formula (3) to make it more accurate in deep sea measurements.

[0052] The present application tests the conductivity sensor 100 under pressure in a seawater constant temperature tank 4, and fits the measured conductivity value and the standard conductivity value with the pressure value to obtain the pressure compensation coefficient of the current conductivity sensor 100. When measuring deep sea, the pressure compensation coefficient is used Correcting the measured conductivity value of the conductivity sensor 100 can greatly improve the accuracy of deep-sea conductivity measurement.

[0053] A specific embodiment of the conductivity sensor pressure compensation test system and method of the present application is provided below.

[0054] The above method was used to test a certain model of three-electrode conductivity sensor, and the test results are shown in Table 1 below.

[0055] Table 1 Conductivity measurement values ​​under different pressures

[0056] Refer to formulas (1) and (2), and convert the standard pressure values ​​in Table 1 (corresponding to ) as independent variable The ratio of each measured conductivity value to the corresponding standard conductivity value is called the conductivity ratio, and each conductivity ratio -1 (corresponding to ) as the dependent variable , using a linear function For all Value and The fitted straight line is as follows: Figure 4 As shown, the fitting straight line is obtained The slope of the fitting is The value is the pressure compensation coefficient The value of When fitting, you can also use the trend line function of the Excel chart, add the trend line formula, and the first-order coefficient is .

[0057] The measured conductivity value is corrected based on formula (3), and the results obtained after pressure and temperature compensation are shown in Table 2 below.

[0058] Table 2 Conductivity correction values ​​under different pressures

[0059] For comparison, the measured conductivity value was corrected using the theoretical pressure compensation coefficient of -9.7E-8. The results obtained after pressure and temperature compensation are shown in Table 3 below.

[0060] Table 3 Conductivity correction values ​​at different pressures when using the theoretical pressure compensation coefficient -9.7E-8

[0061] Comparing the results in Table 2 and Table 3, it can be seen that when the pressure compensation coefficient does not match, the conductivity error (corrected error) will increase with the increase of pressure, exceeding the deep-sea conductivity measurement requirements. The measured conductivity value is corrected, and the error after correction does not exceed 0.0001, which can meet the needs of high-precision measurement of deep-sea conductivity.

[0062] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A conductivity sensor pressure compensation test system, characterized in that: include: Conductivity sensor test device, host computer, standard pressure gauge, seawater constant temperature bath, standard platinum resistance thermometer and temperature measuring bridge; The conductivity sensor testing device comprises a pressure-resistant shell, a temperature sensor and a collection module; the pressure-resistant shell comprises a pressure-resistant cylinder, a pressure-resistant flange and a sealing cylinder; one side of the pressure-resistant flange is connected to the pressure-resistant cylinder, and the other side of the pressure-resistant flange is connected to the sealing cylinder; one end of the pressure-resistant cylinder is an externally threaded pressure pipe interface for connecting the pressure pipe of a standard pressure gauge; the other end of the pressure-resistant cylinder is an internally threaded interface connected to one side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are both located inside the pressure-resistant cylinder; the collection module is located inside the sealing cylinder; the temperature sensor and the conductivity sensor are installed on one side of the pressure-resistant flange, and the collection module is installed on the other side of the pressure-resistant flange; the temperature sensor and the conductivity sensor are electrically connected to the collection module; the collection module is also connected to the host computer for communication; The standard pressure gauge is used to pressurize the conductivity sensor and record the standard pressure value; The seawater constant temperature tank is used to create a standard constant temperature environment for the conductivity sensor; The standard platinum resistance thermometer is placed in a seawater constant temperature bath to measure the standard temperature value; The temperature measuring bridge is connected to a standard platinum resistance thermometer and is used to read and display the standard temperature value measured by the standard platinum resistance thermometer.

2. The conductivity sensor pressure compensation test system according to claim 1, characterized in that: The temperature control fluctuation and uniformity of the seawater constant temperature bath are better than 0.003°C.

3. The conductivity sensor pressure compensation test system according to claim 1, characterized in that: The temperature sensor has the same accuracy as a standard platinum resistance thermometer.

4. The conductivity sensor pressure compensation test system according to claim 1, characterized in that: The pressure-resistant shell is made of stainless steel or titanium.

5. A conductivity sensor pressure compensation test method, characterized in that: A conductivity sensor pressure compensation test system based on any one of claims 1 to 4; The conductivity sensor pressure compensation test method comprises: During the test, fill the conductivity sensor with standard seawater of known salinity and install the pressure-resistant cylinder, then place the conductivity sensor test device in a seawater constant temperature bath; Different temperature control points and pressure combinations are selected in combination with changes in ocean temperature and salinity. The temperature is controlled by a seawater constant temperature tank and the pressure is increased by a standard pressure gauge. When the conductivity measurement value of the conductivity sensor changes non-monotonically within the preset time and the temperature sensor indication is consistent with the standard temperature value displayed by the temperature measuring bridge, the conductivity measurement value, standard pressure value and standard temperature value of the current temperature control point are recorded, and then the temperature and pressure values ​​are changed to perform the next temperature control point test; Calculate the corresponding standard conductivity value according to the standard pressure value, standard temperature value and standard seawater salinity value recorded at each temperature control point; The conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points are fitted to calculate the pressure compensation coefficient; During measurement, the pressure compensation coefficient is used to correct the conductivity measurement value of the conductivity sensor.

6. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The method of filling the conductivity sensor with standard seawater of known salinity and installing a pressure-resistant cylinder specifically includes: Fill the conductivity sensor with standard seawater of known salinity through a self-priming pump, then seal both ends of the conductivity sensor with cut-off clamps and install it on a pressure-resistant flange; After filling the pressure-resistant cylinder with clean water, put it on the pressure-resistant flange and tighten it to reinforce it.

7. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The method of selecting different temperature control points and pressure combinations in combination with changes in ocean temperature and salinity specifically includes: In combination with changes in ocean temperature and salinity, (20℃, 1MPa), (9℃, 5MPa), (4.5℃, 10MPa), (2.5℃, 20MPa), (2℃, 50MPa) and (1.5℃, 70MPa) are selected as different temperature control points and pressure combinations.

8. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The preset time is 10 minutes.

9. The conductivity sensor pressure compensation test method according to claim 5, characterized in that: The conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points are fitted to calculate the pressure compensation coefficient, specifically including: Based on the formula Fit the conductivity measurement values, standard conductivity values ​​and standard pressure values ​​corresponding to all temperature control points to calculate the pressure compensation coefficient ;in For the The conductivity measurement value corresponding to each temperature control point; For the The standard conductivity value corresponding to each temperature control point; For the The standard pressure value corresponding to each temperature control point.

10. The conductivity sensor pressure compensation test method according to claim 9, characterized in that: During the measurement, the conductivity measurement value of the conductivity sensor is corrected using the pressure compensation coefficient, specifically including: When measuring, based on the formula Conductivity measurements for conductivity sensors Make corrections to obtain conductivity correction values Output is performed; is the corresponding pressure measurement value.

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