Four-electrode conductivity sensor response time measuring device and method and readable storage medium

Abstract

The invention relates to the technical field of ocean salinity measurement, and discloses a four-electrode conductivity sensor response time measuring device which comprises a first saline container, a second saline container, a first three-way valve, a second three-way valve, a four-electrode conductivity sensor, constant-temperature water bath equipment, a speed regulating pump, an upper computer, a control circuit and a measuring circuit. In the first saline water container, a water outlet is connected with a port B of the first three-way valve, and a water return port is connected with a port A of the second three-way valve; in the second saline water container, a water outlet is connected with a port A of the first three-way valve, and a water return port is connected with a port B of the second three-way valve and the like; the device can accurately control the rotating speed of the speed regulating pump, and can obtain the response time of the four-electrode conductivity sensor at different flow speeds.

Description

Technical Field

[0001] The present invention relates to the technical field of ocean salinity measurement, and in particular to a device and method for measuring the response time of a four-electrode conductivity sensor and a readable storage medium. Background Art

[0002] High-precision field measuring instruments such as temperature-salinity-depth meters (CTDs) need to be placed in a temperature-controlled seawater tank to conduct experiments at multiple temperature points before use. Usually, a bottle of water sample needs to be taken at each temperature-controlled point in the tank. After the water sample is left to stand for a period of time at room temperature to achieve temperature equilibrium, it is then measured by a high-precision laboratory salinometer (generally using a four-electrode conductivity sensor) to obtain the salinity standard value, and finally the CTD and other instruments are calibrated. In this process, the progress of the tank experiment is greatly slowed down because of the need for sampling and standing. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a four-electrode conductivity sensor response time measurement device, method and readable storage medium. The device, method and readable storage medium can be used to measure the response time of the four-electrode conductivity sensor under different temperature differences, salinity differences and flow rate conditions, help evaluate and correct the measurement error of salinity under dynamic sampling conditions, so that the measurement process of the salinity meter can be carried out synchronously with the water tank experiment, eliminating the steps of seawater sampling and standing, and effectively improving the efficiency of the water tank experiment.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A four-electrode conductivity sensor response time measuring device comprises: a No. 1 salt water container, a No. 2 salt water container, a No. 1 three-way valve, a No. 2 three-way valve, a four-electrode conductivity sensor, a constant temperature water bath device, a speed regulating pump, a host computer, a control circuit and a measuring circuit. In the No. 1 salt water container, the water outlet is connected to the B port of the No. 1 three-way valve, and the water return port is connected to the A port of the No. 2 three-way valve; in the No. 2 salt water container, the water outlet is connected to the A port of the No. 1 three-way valve, and the water return port is connected to the B port of the No. 2 three-way valve; the COM port of the No. 1 three-way valve is connected to the water inlet of the speed regulating pump, the COM port of the No. 2 three-way valve is connected to the water outlet of the speed regulating pump, and the No. 1 three-way valve is connected to the speed regulating pump. A four-electrode conductivity sensor is arranged in the pipeline between the pumps; the No. 1 salt water container, the No. 1 three-way valve, the speed regulating pump and the No. 2 three-way valve form a circulation pipeline of the No. 1 salt water container; the No. 2 salt water container, the No. 1 three-way valve, the speed regulating pump and the No. 2 three-way valve form a circulation pipeline of the No. 2 salt water container; the constant temperature water bath equipment is arranged between the No. 1 three-way valve and the speed regulating pump, and the pipeline where the four-electrode conductivity sensor is located is placed in the constant temperature water bath equipment; the host computer is electrically connected to the control circuit and the measuring circuit respectively, the control circuit is electrically connected to the No. 1 three-way valve, the No. 2 three-way valve and the speed regulating pump respectively, and the measuring circuit is electrically connected to the four-electrode conductivity sensor.

[0006] In the present invention, preferably, the control circuit includes a power supply chip, a serial communication chip, a single-chip microcomputer, a motor drive chip and two optocoupler relays, the power supply chip is respectively connected to the serial communication chip and the single-chip microcomputer, the single-chip microcomputer is respectively connected to the two optocoupler relays, the No. 1 three-way valve and the No. 2 three-way valve are each connected to an optocoupler relay, the motor drive chip is respectively connected to the single-chip microcomputer and the speed regulating pump, and the serial communication chip is connected to the host computer.

[0007] In the present invention, preferably, the power chip adopts ME6241, the serial communication chip adopts MAX3221, the single-chip microcomputer adopts GD32L233, the motor drive chip adopts DRV10987, and the optocoupler relay adopts AQZ102.

[0008] In the present invention, preferably, the measuring circuit comprises: a measuring circuit power supply chip, a measuring circuit single-chip microcomputer, a communication chip, an analog-to-digital conversion chip and a switch chip; the measuring circuit power supply chip is respectively connected to the analog-to-digital conversion chip, the communication chip, the measuring circuit single-chip microcomputer and the switch chip for power supply; the measuring circuit single-chip microcomputer is connected to the communication chip through a universal asynchronous receiver-transmitter interface for receiving measurement instructions and sending conductivity measurement data; the measuring circuit single-chip microcomputer is connected to the analog-to-digital conversion chip through a serial peripheral device interface; the AIN1 port and the AIN2 port of the analog-to-digital conversion chip are respectively connected to the two ends of a standard resistor R for collecting the differential voltage across the two ends of the standard resistor R; the AIN3 port and the AIN4 port of the analog-to-digital conversion chip are respectively connected to the four-electrode conductivity sensor Two voltage electrodes V1 and V2 are used to collect the differential voltage across the two voltage electrodes V1 and V2; the AIN0 port of the analog-to-digital conversion chip is connected to the COM1 port of the switch chip, and the AIN0 port of the analog-to-digital conversion chip is used to generate a constant current I; the COM2 port of the switch chip is grounded, the NO1 port of the switch chip is respectively connected to one end of the standard resistor R and the NC2 port of the switch chip, the other end of the standard resistor R is connected to the current electrode I1 of the four-electrode conductivity sensor, the NC1 port of the switch chip is respectively connected to the current electrode I2 of the four-electrode conductivity sensor and the NO2 port of the switch chip, and the IN1 port and IN2 port of the switch chip are both connected to the PWM signal output interface of the measurement circuit microcontroller.

[0009] A four-electrode conductivity sensor response time measurement method, using a four-electrode conductivity sensor response time measurement device as described in any one of claims 1 to 4, the four-electrode conductivity sensor response time measurement method comprising: S1, setting the temperature value of a constant temperature water bath device, and injecting salt water of different concentrations into the first salt water container and the second salt water container respectively; S2, starting a speed regulating pump to discharge bubbles from the circulation pipeline of the first salt water container and the circulation pipeline of the second salt water container; S3, opening the circulation pipeline of the first salt water container and closing the circulation pipeline of the second salt water container. Container circulation pipeline; S4, start the measurement circuit, measure the conductivity data of the circulation pipeline of the No. 1 salt water container for M seconds; S5, close the B port of the No. 1 three-way valve and open the A port, delay for X seconds, close the A port of the No. 2 three-way valve and open the B port, measure the measurement data of the salt water step process from the No. 1 salt water container to the No. 2 salt water container, and the value of X is equal to the time for the salt water in the pipeline to flow from the No. 1 three-way valve to the No. 2 three-way valve; S6, measure the conductivity data of the circulation pipeline of the No. 2 salt water container for N seconds; S7, calculate the response time of the four-electrode conductivity sensor.

[0010] In the present invention, preferably, the formula used in S7 is:

[0011]

[0012] Where t is the test time, τ is the response time of the four-electrode conductivity sensor, C (t) is the conductivity value of the four-electrode conductivity sensor at the test time t; C g is the stable conductivity value of the four-electrode conductivity sensor in the circulation pipeline of the No. 2 salt water container, taking the median of the last 1 / 10 of the measured data; C a is the stable conductivity measurement value of the four-electrode conductivity sensor in the circulation pipeline of the No. 1 salt water container, taking the median of the first 1 / 10 of the measurement data; t0 is the moment when the sensor starts to absorb the salt water in the No. 2 salt water container.

[0013] In the present invention, preferably, the value of M is greater than 10 times the sensor response time.

[0014] In the present invention, preferably, the value of N is greater than 10 times the sensor response time.

[0015] In the present invention, preferably, the sampling time interval for measuring conductivity by the four-electrode conductivity sensor is 1 ms or 2 ms.

[0016] A computer-readable storage medium comprises instructions. When the instructions are executed on a computer, the computer is enabled to execute the four-electrode conductivity sensor response time measurement method as described in any one of the above.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The device and method can accurately control the speed of the speed regulating pump and obtain the response time of the four-electrode conductivity sensor under different flow rates;

[0019] 2) The device and method can obtain the response time of the four-electrode conductivity sensor under different salinity differences by mixing seawater of different salinities in two containers;

[0020] 3) The device and method can obtain the response time of the four-electrode conductivity sensor under different temperature differences by changing the temperature of the constant temperature water bath;

[0021] 4) The device and method can alternately switch the No. 1 three-way valve and the No. 2 three-way valve at precise time intervals, thereby minimizing the mixing of seawater in the two salt water containers and ensuring the consistency of multiple measurement results;

[0022] 5) The device and method adopt a multi-point data fitting method to calculate the response time. Compared with the traditional area method, slope method, direct mapping method, etc., it can overcome the shortcomings of low accuracy and being greatly affected by human factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of a four-electrode conductivity sensor response time measurement device according to an embodiment of the present invention.

[0024] Figure 2 Schematic diagram of the structure of the control circuit in the response time measurement device of the four-electrode conductivity sensor according to an embodiment of the present invention.

[0025] Figure 3 Schematic diagram of the structure of the measurement circuit in the response time measurement device of the four-electrode conductivity sensor according to an embodiment of the present invention.

[0026] Figure 4 This is a flow chart of a method for measuring response time of a four-electrode conductivity sensor according to an embodiment of the present invention.

[0027] Figure 5 Schematic diagram of measurement results of a method for measuring response time of an electrode conductivity sensor according to an embodiment of the present invention.

[0028] In the attached figure: 1. No. 1 salt water container; 2. No. 2 salt water container; 3. No. 1 three-way valve; 4. No. 2 three-way valve; 5. Four-electrode conductivity sensor; 6. Constant temperature water bath equipment; 7. Speed ​​regulating pump; 8. Host computer; 9. Control circuit; 91. Power chip; 92. Serial communication chip; 93. Single-chip microcomputer; 94. Motor drive chip; 95. Optocoupler relay; 10. Measurement circuit; 101. Measurement circuit power chip; 102. Measurement circuit single-chip microcomputer; 103. Communication chip; 104. Analog-to-digital conversion chip; 105. Switch chip. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0032] See also Figure 1 A preferred embodiment of the present invention provides a response time measurement device for a four-electrode conductivity sensor 5, comprising: a No. 1 salt water container 1, a No. 2 salt water container 2, a No. 1 three-way valve 3, a No. 2 three-way valve 4, a four-electrode conductivity sensor 5, a constant temperature water bath device 6, a speed regulating pump 7, a host computer 8, a control circuit 9 and a measurement circuit 10. In the No. 1 salt water container 1, the water outlet is connected to the B port of the No. 1 three-way valve 3, and the water return port is connected to the A port of the No. 2 three-way valve 4. In the No. 2 salt water container 2, the water outlet is connected to the A port of the No. 1 three-way valve 3, and the water return port is connected to the B port of the No. 2 three-way valve 4. The COM port of the No. 1 three-way valve 3 is connected to the water inlet of the speed regulating pump 7, the COM port of the No. 2 three-way valve 4 is connected to the water outlet of the speed regulating pump 7, and a four-electrode conductivity sensor 5 is arranged in the pipeline between the No. 1 three-way valve 3 and the speed regulating pump 7. The No. 1 salt water container 1, the No. 1 three-way valve 3, the speed regulating pump 7, and the No. 2 three-way valve 4 form a circulation pipeline of the No. 1 salt water container 1, and the No. 2 salt water container 2, the No. 1 three-way valve 3, the speed regulating pump 7, and the No. 2 three-way valve 4 form a circulation pipeline of the No. 2 salt water container 2. The constant temperature water bath equipment 6 is arranged between the No. 1 three-way valve 3 and the speed regulating pump 7, and the pipeline where the four-electrode conductivity sensor 5 is located is placed in the constant temperature water bath equipment 6. The upper computer 8 is electrically connected to the control circuit 9 and the measuring circuit 10 respectively, the control circuit 9 is electrically connected to the No. 1 three-way valve 3, the No. 2 three-way valve 4 and the speed regulating pump 7 respectively, and the measuring circuit 10 is electrically connected to the four-electrode conductivity sensor 5.

[0033] The first salt water container 1 and the second salt water container 2 contain salt solutions of different concentrations (simulating seawater of different salinities, the salt solutions herein can also be generally referred to as salt water or seawater), the water outlet is located at the lower end of the container, and the water return port is located at the upper end of the container. Figure 1 As shown, the red and blue lines represent the circulation pipelines of the two brine, the green line represents the pipeline shared by the two brine, and the arrow represents the flow direction of the brine in the pipeline. The four-electrode conductivity sensor 5 is immersed in a constant temperature water bath device 6, and the water bath temperature is adjustable. The No. 1 three-way valve 3 and the No. 2 three-way valve 4 are used to switch between the two brine media, and the switching of the three-way valves is controlled by the control circuit 9. The speed regulating pump 7 is used to adjust the flow rate of the pipeline, and the speed of the speed regulating pump 7 is controlled by the control circuit 9.

[0034] like Figure 2As shown, in a preferred embodiment of the present invention, the control circuit 9 includes a power supply chip 91, a serial communication chip 92, a single-chip microcomputer 93, a motor drive chip 94 and two optocoupler relays 95. The power supply chip 91 is connected to the serial communication chip 92 and the single-chip microcomputer 93 respectively, the single-chip microcomputer 93 is connected to the two optocoupler relays 95 respectively, the No. 1 three-way valve 3 and the No. 2 three-way valve 4 are each connected to an optocoupler relay 95, the motor drive chip 94 is connected to the single-chip microcomputer 93 and the speed regulating pump 7 respectively, and the serial communication chip 92 is connected to the host computer 8.

[0035] Furthermore, the power chip 91 adopts ME6241, the serial communication chip 92 adopts MAX3221, the single chip computer 93 adopts GD32L233, the motor drive chip 94 adopts DRV10987, and the optical coupler relay 95 adopts AQZ102.

[0036] The control circuit 9 in the device is used to control the switch of the three-way valve and adjust the speed of the speed regulating pump 7. The control circuit 9 is composed of a power chip 91 (ME6241), a serial communication chip 92 (MAX3221), a single-chip microcomputer 93 (GD32L233), an optical coupler relay 95 (AQZ102), and a motor drive chip 94 (DRV10987). The principle diagram is as follows Figure 2 As shown. The power input is 24V, which supplies the optocoupler relay 95, the motor driver chip 94 and the power chip 91 (ME6241). The power chip 91 generates a 3.3V power supply, which supplies the single-chip microcomputer 93 (GD32L233) and the serial communication chip 92 (MAX3221). The single-chip microcomputer 93 controls the optocoupler relay 95 through the high and low levels of the IO1 and IO2 pins to switch the No. 1 three-way valve 3 and the No. 2 three-way valve 4. The single-chip microcomputer 93 controls the motor driver chip 94 through the PWM square wave to control the speed of the speed regulating pump 7. The single-chip microcomputer 93 receives the instructions of the upper computer 8 to switch the three-way valve and control the speed regulating pump 7 through the communication chip 103.

[0037] like Figure 3As shown, in a preferred embodiment of the present invention, the measuring circuit 10 includes: a measuring circuit power chip 101, a measuring circuit single chip computer 102, a communication chip 103, an analog-to-digital conversion chip 104 and a switch chip 105. The measuring circuit power chip 101 (ME6214) is respectively connected to the analog-to-digital conversion chip 104, the communication chip 103, the measuring circuit single chip computer 102 and the switch chip 105 for power supply. The measuring circuit single chip computer 102 (GD32L233) is connected to the communication chip 103 (MAX3232) through a universal asynchronous receiver and transmitter interface, and is used to receive measurement instructions and send conductivity measurement data. The measuring circuit single chip computer 102 is connected to the analog-to-digital conversion chip 104 (HTC6761Q) through a serial peripheral device interface. The AIN1 port and the AIN2 port of the analog-to-digital conversion chip 104 are respectively connected to the two ends of the standard resistor R, and are used to collect the differential voltage across the two ends of the standard resistor R. The AIN3 port and the AIN4 port of the analog-to-digital conversion chip 104 are respectively connected to the two voltage electrodes V1 and V2 of the four-electrode conductivity sensor 5, and are used to collect the differential voltage at both ends of the two voltage electrodes V1 and V2. The AIN0 port of the analog-to-digital conversion chip 104 is connected to the COM1 port of the switch chip 105 (RS2105), and the AIN0 port of the analog-to-digital conversion chip 104 is used to generate a constant current I. The COM2 port of the switch chip 105 is grounded, the NO1 port of the switch chip 105 is respectively connected to one end of the standard resistor R and the NC2 port of the switch chip 105, the other end of the standard resistor R is connected to the current electrode I1 of the four-electrode conductivity sensor 5, the NC1 port of the switch chip 105 is respectively connected to the current electrode I2 of the four-electrode conductivity sensor 5 and the NO2 port of the switch chip 105, and the IN1 port and the IN2 port of the switch chip 105 are both connected to the PWM signal output interface of the measurement circuit microcontroller 102.

[0038] Another embodiment of the present invention provides a four-electrode conductivity sensor response time measurement method, using the four-electrode conductivity sensor response time measurement device of the above embodiment, such as Figure 4 As shown, the response time measurement method of the four-electrode conductivity sensor includes:

[0039] S1, set the temperature value of the constant temperature water bath equipment, and inject salt water of different concentrations into salt water container No. 1 and salt water container No. 2 respectively.

[0040] Use pure water, sodium chloride, a measuring cup and a balance at room temperature to prepare two salinity salt water (salt solution) and place them in two containers, stir them evenly and cover them with lids. The temperature value of the constant temperature water bath equipment is set at a temperature different from room temperature to reflect the temperature difference of the environment where the four-electrode conductivity sensor 5 is located. If there is no need to set the temperature difference, the temperature of the constant temperature water bath can also be set to room temperature.

[0041] S2, start the speed regulating pump to discharge the bubbles in the circulation pipelines of the No. 1 brine container and the No. 2 brine container.

[0042] The power of the speed regulating pump 7 is used to control the three-way valve, switch the No. 1 three-way valve 3 to the B port and the No. 2 three-way valve 4 to the A port, and discharge the bubbles in the No. 1 salt water container circulation pipeline. Switch the No. 1 three-way valve 3 to the A port and the No. 2 three-way valve 4 to the B port, and discharge the bubbles in the No. 2 salt water container circulation pipeline.

[0043] S3, open the circulation pipeline of brine container No. 1 and close the circulation pipeline of brine container No. 2.

[0044] Before the test, adjust the water sample switching device to the No. 1 salt water container circulation pipeline. At this time, the No. 1 three-way valve 3 points to the B port, and the No. 2 three-way valve 4 points to the A port.

[0045] S4, start the measuring circuit and measure the conductivity data of the circulation pipeline of the No. 1 salt water container for M seconds.

[0046] At this time, the host computer 8 starts to record the measurement data. The conductivity data of the No. 1 salt water is measured for M seconds. In order to reflect the stable state of the conductivity of the four-electrode conductivity sensor 5 in the No. 1 salt water, the value of M should be larger, and a stable curve can be seen on the image. Preferably, the value of M is greater than 10 times the response time of the four-electrode conductivity sensor. Here, the response time of the four-electrode conductivity sensor is a value estimated based on multiple experiments. The value of M is determined based on this estimated value, and it does not need to be very precise.

[0047] S5, close port B of No. 1 three-way valve and open port A, delay X seconds, close port A of No. 2 three-way valve and open port B, measure the measurement data of the brine step process from the No. 1 brine container to the No. 2 brine container, and the value of X is equal to the time it takes for the brine in the pipeline to flow from the No. 1 three-way valve to the No. 2 three-way valve.

[0048] Alternately switch the No. 1 three-way valve 3 to A and the No. 2 three-way valve 4 to B, with a delay of X seconds in between, and measure the measurement data of the step process from No. 1 salt water to No. 2 salt water. The value of X is an empirical value obtained through continuous observation and testing during the experiment.

[0049] S6, measuring the conductivity data of the circulation pipeline of the second salt water container for N seconds.

[0050] Continue to measure the conductivity data of the second salt water for N seconds, and the host computer 8 stops recording the measured data. Similarly, in order to reflect the stable state of the conductivity of the four-electrode conductivity sensor 5 in the second salt water, the value of N should be larger, and a stable curve can be seen on the image. Preferably, the value of N is greater than 10 times the response time of the four-electrode conductivity sensor. Here, the response time of the four-electrode conductivity sensor is a value estimated based on multiple experiments, and the value of N is determined based on this estimated value, and it does not need to be very precise.

[0051] S7, calculating the response time of the four-electrode conductivity sensor.

[0052] Specifically, the formula used by S7 is:

[0053]

[0054] Where t is the test time, τ is the response time of the four-electrode conductivity sensor, C (t) is the conductivity value of the four-electrode conductivity sensor at the test time t; C g is the stable conductivity value of the four-electrode conductivity sensor in the circulation pipeline of the No. 2 salt water container, taking the median of the last 1 / 10 of the measured data; C a is the stable conductivity measurement value of the four-electrode conductivity sensor in the circulation pipeline of the No. 1 salt water container, taking the median of the first 1 / 10 of the measurement data; t0 is the moment when the sensor starts to absorb the salt water in the No. 2 salt water container.

[0055] The upper computer 8 of the device is used to control the measurement circuit 10 and the control circuit 9, obtain the measurement data and calculate the response time of the four-electrode conductivity sensor. The above calculation formula is derived according to a certain fitting method. Specifically, due to the combined influence of seawater turbulence, mixing, pipe wall adhesion and sensor platinum ring width, the conductivity sensor step curve is difficult to accurately describe with a theoretical model. In practice, its response time is generally evaluated according to a first-order model. The present invention adopts a multi-point data fitting method to calculate the response time of the sensor.

[0056] The differential equation for the first-order system is:

[0057]

[0058] Where: t: test time; τ: response time of four-electrode conductivity sensor; C (t) : conductivity value of the four-electrode conductivity sensor at the test time t; C g : Stable conductivity values ​​of the four-electrode conductivity sensor in salt water 2.

[0059] Let \(t_0\) be the moment when the sensor starts to suck the brine in the second brine container. Assume that when \(t \lt t_0\), the sensor is filled with brine 1 and maintains a constant flow rate. At the moment \(t = t_0\), the four-electrode conductivity sensor starts to suck brine 2. Then the general solution of formula (1) is:

[0060]

[0061] For the convenience of calculation, the part of formula (2) when \(t \gt t_0\) is transformed into:

[0062]

[0063] In the formula: \(C\) a : The stable conductivity measurement value of the four-electrode conductivity sensor in brine 1, taking the median of the first 1 / 10 of the measurement data; \(C\) g : Taking the median of the last 1 / 10 of the measurement data; \(C\) (t) Taking the conductivity values within the range from \(C\) a + (\(C\) g - \(C\) a ) * 10% to \(C\) a + (\(C\) g - \(C\) a ) * 90% of all the measurement data ((\(t_1\), \(C\) (t1) ), (\(t_2\), \(C\) (t2) ), (\(t_3\), \(C\) (t3) )...).

[0064] Substitute the sequences of \(C\) A , \(C\) G , \(C\) (t) into formula (3) for linear fitting, and the response time \(\tau\) of the sensor can be accurately calculated.

[0065] The sampling time interval for the four-electrode conductivity sensor to measure conductivity depends on its circuit frequency. Preferably, the circuit frequency can be 1000 Hz or 500 Hz, and the corresponding sampling time intervals are 1 ms or 2 ms.

[0066] The data curve measured using the device and method of the present invention is as shown in Figure 5 . From it, the response time of the four-electrode conductivity sensor in this example can be calculated as 47 ms.

[0067] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, each process of the above-mentioned four-electrode conductivity sensor response time measurement method embodiment is implemented, and the same technical effect can be achieved. Among them, the computer-readable storage medium can be of various types, such as read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), a disk or an optical disk, etc.

[0068] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A four-electrode conductivity sensor response time measuring device, characterized in that: include: No. 1 salt water container, No. 2 salt water container, No. 1 three-way valve, No. 2 three-way valve, four-electrode conductivity sensor, constant temperature water bath equipment, speed regulating pump, host computer, control circuit and measurement circuit, In the No. 1 salt water container, the water outlet is connected to the B port of the No. 1 three-way valve, and the water return port is connected to the A port of the No. 2 three-way valve; In the No. 2 salt water container, the water outlet is connected to the A port of the No. 1 three-way valve, and the water return port is connected to the B port of the No. 2 three-way valve; The COM port of the No. 1 three-way valve is connected to the water inlet of the speed regulating pump, the COM port of the No. 2 three-way valve is connected to the water outlet of the speed regulating pump, a four-electrode conductivity sensor is arranged in the pipeline between the No. 1 three-way valve and the speed regulating pump, the No. 1 salt water container, the No. 1 three-way valve, the speed regulating pump, and the No. 2 three-way valve form a No. 1 salt water container circulation pipeline, and the No. 2 salt water container, the No. 1 three-way valve, the speed regulating pump, and the No. 2 three-way valve form a No. 2 salt water container circulation pipeline; The constant temperature water bath equipment is arranged between the No. 1 three-way valve and the speed regulating pump, and the pipeline where the four-electrode conductivity sensor is located is placed in the constant temperature water bath equipment; The host computer is electrically connected to the control circuit and the measuring circuit respectively, the control circuit is electrically connected to the No. 1 three-way valve, the No. 2 three-way valve and the speed regulating pump respectively, and the measuring circuit is electrically connected to the four-electrode conductivity sensor.

2. The four-electrode conductivity sensor response time measurement device according to claim 1, characterized in that: The control circuit includes a power supply chip, a serial communication chip, a single-chip microcomputer, a motor drive chip and two optocoupler relays. The power supply chip is respectively connected to the serial communication chip and the single-chip microcomputer, the single-chip microcomputer is respectively connected to the two optocoupler relays, the No. 1 three-way valve and the No. 2 three-way valve are each connected to an optocoupler relay, the motor drive chip is respectively connected to the single-chip microcomputer and the speed regulating pump, and the serial communication chip is connected to the host computer.

3. The four-electrode conductivity sensor response time measuring device according to claim 2, characterized in that: The power chip adopts ME6241, the serial communication chip adopts MAX3221, the single-chip microcomputer adopts GD32L233, the motor drive chip adopts DRV10987, and the optical coupler relay adopts AQZ102.

4. The four-electrode conductivity sensor response time measurement device according to claim 1, characterized in that: The measuring circuit comprises: a measuring circuit power supply chip, a measuring circuit single chip computer, a communication chip, an analog-to-digital conversion chip and a switch chip; The measuring circuit power supply chip is respectively connected to the analog-to-digital conversion chip, the communication chip, the measuring circuit single chip computer and the switch chip for power supply; The measurement circuit single chip microcomputer is connected to the communication chip via a universal asynchronous receiver and transmitter interface, and is used to receive measurement instructions and send conductivity measurement data; The measurement circuit single chip microcomputer is connected to the analog-to-digital conversion chip via a serial peripheral device interface; The AIN1 port and the AIN2 port of the analog-to-digital conversion chip are respectively connected to the two ends of the standard resistor R, and are used to collect the differential voltage across the two ends of the standard resistor R; the AIN3 port and the AIN4 port of the analog-to-digital conversion chip are respectively connected to the two voltage electrodes V1 and V2 of the four-electrode conductivity sensor, and are used to collect the differential voltage across the two voltage electrodes V1 and V2; the AIN0 port of the analog-to-digital conversion chip is connected to the COM1 port of the switch chip, and the AIN0 port of the analog-to-digital conversion chip is used to generate a constant current I; The COM2 port of the switch chip is grounded, the NO1 port of the switch chip is respectively connected to one end of the standard resistor R and the NC2 port of the switch chip, the other end of the standard resistor R is connected to the current electrode I1 of the four-electrode conductivity sensor, the NC1 port of the switch chip is respectively connected to the current electrode I2 of the four-electrode conductivity sensor and the NO2 port of the switch chip, and the IN1 port and IN2 port of the switch chip are both connected to the PWM signal output interface of the measurement circuit microcontroller.

5. A method for measuring the response time of a four-electrode conductivity sensor, characterized in that: Using the four-electrode conductivity sensor response time measurement device according to any one of claims 1 to 4, the four-electrode conductivity sensor response time measurement method comprises: S1, setting the temperature value of the constant temperature water bath equipment, and injecting salt water of different concentrations into the first salt water container and the second salt water container respectively; S2, start the speed regulating pump to discharge the bubbles in the circulation pipeline of the No. 1 salt water container and the circulation pipeline of the No. 2 salt water container; S3, opening the circulation pipeline of the No. 1 salt water container and closing the circulation pipeline of the No. 2 salt water container; S4, start the measuring circuit and measure the conductivity data of the circulation pipeline of the No. 1 salt water container for M seconds; S5, the B port of the No. 1 three-way valve is closed and the A port is opened, and a delay of X seconds is made. The A port of the No. 2 three-way valve is closed and the B port is opened, and the measurement data of the brine step process from the No. 1 brine container to the No. 2 brine container is measured, and the value of X is equal to the time it takes for the brine in the pipeline to flow from the No. 1 three-way valve to the No. 2 three-way valve; S6, measuring the conductivity data of the circulation pipeline of the second salt water container for N seconds; S7, calculating the response time of the four-electrode conductivity sensor.

6. The method for measuring the response time of a four-electrode conductivity sensor according to claim 5, characterized in that: The formula used in S7 is: Where t is the test time, τ is the response time of the four-electrode conductivity sensor, C (t) is the conductivity value of the four-electrode conductivity sensor at the test time t; C g is the stable conductivity value of the four-electrode conductivity sensor in the circulation pipeline of the No. 2 salt water container, taking the median of the last 1 / 10 of the measured data; C a is the stable conductivity measurement value of the four-electrode conductivity sensor in the circulation pipeline of the No. 1 salt water container, taking the median of the first 1 / 10 of the measurement data; t0 is the moment when the sensor starts to absorb the salt water in the No. 2 salt water container.

7. The method for measuring the response time of a four-electrode conductivity sensor according to claim 5, characterized in that: The value of M is greater than 10 times the sensor response time.

8. The method for measuring the response time of a four-electrode conductivity sensor according to claim 5, characterized in that: The value of N is greater than 10 times the sensor response time.

9. The method for measuring the response time of a four-electrode conductivity sensor according to claim 5, characterized in that: The sampling time interval of the four-electrode conductivity sensor for measuring conductivity is 1ms or 2ms.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes instructions, and when the instructions are executed on a computer, the computer is caused to perform the four-electrode conductivity sensor response time measurement method according to any one of claims 5 to 9.

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