Measuring method and system of low-conductivity electromagnetic flowmeter and storage medium

Abstract

The invention provides a measuring method and system of a low-conductivity electromagnetic flowmeter and a storage medium. The method comprises the steps that the measured flow value, obtained by a flow electrode, of a medium in a pipeline and the medium conductivity, obtained by a conductivity electrode, of the medium in the pipeline are obtained; whether the medium conductivity falls into a preset conductivity compensation range or not is judged, if not, whether the medium conductivity exceeds the preset conductivity compensation range or not is judged, and if not, an empty pipe signal representing that the pipeline is in an empty pipe state is generated; if yes, generating an uncompensated signal representing that flow compensation does not need to be carried out; if yes, a flow compensation coefficient is obtained, a flow compensation value needing flow compensation is determined based on the medium conductivity and the flow compensation coefficient, and the actual flow value of the medium in the pipeline is obtained by adding the measured flow value to the flow compensation value. The accuracy of a measurement result when the electromagnetic flowmeter measures a medium can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of electromagnetic flowmeters, and in particular to a measurement method, system and storage medium for a low-conductivity electromagnetic flowmeter. Background Art

[0002] Electromagnetic flowmeter is a flowmeter based on Faraday's law of electromagnetic induction. It calculates the flow rate by measuring the change in electromagnetic field energy flowing in a conductive liquid. As a non-invasive flow measurement tool, electromagnetic flowmeter has become the preferred measurement equipment in many industries, including chemical, pharmaceutical, water treatment and food processing, due to its unimpeded flow of fluids, low pressure loss and adaptability to fluid types (such as corrosive or solid liquids). However, the traditional electromagnetic flowmeter on the market requires a conductivity range of 5μs / cm for the measured medium. In the face of the medical and environmental protection industries, pure water and ultrapure water with a conductivity as low as 1μs / cm are commonly used, which makes it impossible for conventional electromagnetic flowmeters to measure accurately. After all, the signal source internal resistance of the low conductivity medium is large, and the flow signal received by the flowmeter is attenuated, which will lead to measurement errors, or the electromagnetic flowmeter is mistakenly judged to be in an empty pipe state without measurement. Summary of the invention

[0003] In order to improve the accuracy of measurement results when an electromagnetic flowmeter measures a medium, an embodiment of the present application provides a measurement method, system and storage medium for a low-conductivity electromagnetic flowmeter.

[0004] In a first aspect, this embodiment provides a method for measuring a low-conductivity electromagnetic flowmeter, the method comprising: Obtaining a measured flow value of the medium in the pipeline obtained by the flow electrode and a medium conductivity of the medium in the pipeline obtained by the conductivity electrode; Determine whether the medium conductivity falls within a preset conductivity compensation range; if not, determine whether the medium conductivity exceeds the preset conductivity compensation range; if not, generate an empty pipe signal indicating that the pipeline is in an empty pipe state; If it exceeds, a non-compensated signal is generated indicating that no flow compensation is required; If it does, obtain a flow compensation coefficient, determine a flow compensation value that needs to be used to compensate the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain the actual flow value of the medium in the pipeline.

[0005] In some embodiments, the conductivity electrode includes a first conductivity electrode and a second conductivity electrode, the first conductivity electrode is connected to a power supply via a set resistor, the second conductivity electrode is grounded, and the medium conductivity of the medium in the pipeline obtained by the conductivity electrode includes: Obtaining a measured voltage value between the first conductivity electrode and the second conductivity electrode, multiplying the measured voltage value by a set resistance value of the set resistor, and dividing the result by a voltage difference between a power supply voltage of the power supply and the measured voltage value, so as to obtain an electrode resistance formed by the first conductivity electrode and the second conductivity electrode; A preset conductivity-resistance calculation relationship is obtained, and the electrode resistance is substituted into the calculation relationship to obtain the medium conductivity of the medium in the pipeline.

[0006] In some embodiments, the preset conductivity compensation range includes a conductivity compensation upper limit value and a conductivity compensation lower limit value, and a conductivity reference value is further provided between the conductivity compensation upper limit value and the conductivity compensation lower limit value, and the method further includes: The empty pipe conductivity value of the pipeline in the empty pipe state during the test phase and the set threshold are obtained, the empty pipe conductivity value is subtracted from the conductivity reference value, multiplied by the threshold, and then added to the empty pipe conductivity value to obtain the conductivity compensation lower limit value.

[0007] In some of these embodiments, the method further comprises: Obtaining, under a set flow rate condition, a first flow rate value measured by the electromagnetic flowmeter when the conductivity is the conductivity compensation upper limit value, and a second flow rate value measured when the conductivity is the conductivity reference value; The first flow compensation ratio is obtained by subtracting the first flow value from the value one and dividing it by the set flow value corresponding to the set flow; the second flow compensation ratio is obtained by subtracting the second flow value from the value one and dividing it by the set flow value corresponding to the set flow; the flow compensation coefficient is obtained by dividing the compensation ratio difference between the second flow compensation ratio and the first flow compensation ratio by the conductivity compensation difference between the conductivity reference value and the conductivity compensation upper limit value.

[0008] In some embodiments, determining the flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient includes: Based on the flow compensation coefficient, the conductivity compensation upper limit value and the first flow compensation ratio, or based on the flow compensation coefficient, the conductivity reference value and the second flow compensation ratio, a flow compensation relationship is obtained; Substitute the medium conductivity into the flow compensation relationship to obtain the flow compensation ratio required to compensate the flow; divide the flow measurement value by the difference between the value one and the flow compensation ratio, and then subtract the flow measurement value to obtain the flow compensation value required to compensate the flow.

[0009] In some embodiments, the flow electrode includes a first flow electrode and a second flow electrode, and the first flow electrode, the second flow electrode, the first conductivity electrode and the second conductivity electrode are evenly arranged on the outer wall of the pipeline along the circumference of the pipeline and are alternately distributed.

[0010] In some of the embodiments, if the medium conductivity does not exceed the preset conductivity compensation range, the method further includes: generating an alarm signal.

[0011] In some of the embodiments, if the medium conductivity exceeds the preset conductivity compensation range, the method further includes: determining the measured flow value as an actual flow value of the medium in the pipeline.

[0012] In a second aspect, this embodiment provides a measurement system for a low-conductivity electromagnetic flowmeter, the system comprising: a flow electrode module, a conductivity electrode module and a compensation module; wherein: The flow electrode module is used to obtain the measured flow value of the medium in the pipeline obtained by the flow electrode; The conductivity electrode module is used to obtain the medium conductivity of the medium in the pipeline obtained by the conductivity electrode; The compensation module is used to determine whether the medium conductivity falls within a preset conductivity compensation range. If not, determine whether the medium conductivity exceeds the preset conductivity compensation range. If not, generate an empty pipe signal indicating that the pipeline is in an empty pipe state; if exceeded, generate a no compensation signal indicating that no flow compensation is required; if within, obtain a flow compensation coefficient, determine a flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain an actual flow value of the medium in the pipeline.

[0013] In a third aspect, this embodiment provides a computer-readable storage medium on which a computer program that can be run on a processor is stored. When the computer program is executed by the processor, a measurement method for a low-conductivity electromagnetic flowmeter as described in the first aspect is implemented.

[0014] By adopting the above method, the present application first obtains the measured flow value of the medium in the pipeline obtained by the flow electrode, and the medium conductivity of the medium in the pipeline obtained by the conductivity electrode. Then, it is determined whether the medium conductivity falls within the preset conductivity compensation range. If not, it is determined whether the medium conductivity exceeds the preset conductivity compensation range. If not, an empty pipe signal is generated to indicate that the pipeline is in an empty pipe state. If it exceeds, a non-compensated signal is generated to indicate that no flow compensation is required.

[0015] If it falls, obtain the flow compensation coefficient, determine the flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain the actual flow value of the medium in the pipeline. In this way, by introducing the conductivity electrode, the medium conductivity of the medium in the pipeline is first determined, so as to determine whether the flow needs to be compensated according to the medium conductivity. When it is determined that the flow needs to be compensated, the flow compensation value that needs to be compensated for the flow is indirectly obtained according to the medium conductivity. Finally, the measured flow value that has been lost is added to the obtained flow compensation value to obtain the actual flow value that can truly reflect the flow of the medium in the pipeline, so as to improve the accuracy of the measurement results when the electromagnetic flowmeter measures the medium. Moreover, on the basis of the electromagnetic flowmeter that originally measures the conductivity of 5μs / cm, it is only necessary to add the conductivity electrode and the corresponding converter part, and it is not necessary to replace the new electromagnetic flowmeter to increase the accurate measurement of the flow of the medium at the conductivity compensation lower limit value ~ 5μs / cm conductivity, which can save costs compared to replacing the electromagnetic flowmeter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the electromagnetic flowmeter in the prior art provided by the present application measuring the medium in the pipeline.

[0017] Figure 2 It is a schematic diagram of the electromagnetic flowmeter provided in an embodiment of the present application measuring the medium in the pipeline.

[0018] Figure 3 This is a block diagram of a measurement method for a low-conductivity electromagnetic flowmeter provided in an embodiment of the present application.

[0019] Figure 4 It is a schematic diagram of a circuit consisting of conductivity electrodes and pipelines provided in an embodiment of the present application.

[0020] Figure 5 This is a block diagram for obtaining a flow compensation coefficient provided in an embodiment of the present application.

[0021] Figure 6 This is a measurement system framework diagram of a low-conductivity electromagnetic flowmeter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. However, it should be understood by those of ordinary skill in the art that the present application can be implemented without these details. For those of ordinary skill in the art, it is obvious that various changes can be made to the embodiments disclosed in the present application, and without departing from the principles and scope of the present application, the general principles defined in the present application can be applied to other embodiments and application scenarios. Therefore, the present application is not limited to the embodiments shown, but conforms to the broadest scope consistent with the scope claimed for protection in the present application.

[0023] The embodiments of the present application are further described in detail below in conjunction with the drawings in the specification.

[0024] Figure 1 Schematic diagram of the electromagnetic flowmeter in the prior art provided by this application measuring the medium in the pipeline. Figure 1 As shown, the electromagnetic flowmeter includes a sensor part, a converter part and a main control chip. Among them, the sensor part includes a flow measurement electrode, which is two electrodes or three electrodes. The three electrodes refer to adding a grounding electrode on the basis of two electrodes. When the electromagnetic flowmeter is working normally, the sensor part must be grounded through the casing, or directly grounded through the grounding electrode. The converter part includes a flow signal acquisition circuit. The main control chip receives the voltage value at the output end of the converter part to obtain the instantaneous flow of the medium in the pipeline, and uses it as the actual flow of the medium in the pipeline, so as to output it accordingly or send it to other devices as needed.

[0025] Figure 2 FIG. 1 is a schematic diagram of an electromagnetic flowmeter provided in an embodiment of the present application measuring a medium in a pipeline. Figure 2As shown, the electromagnetic flowmeter provided in this embodiment also includes three parts: a sensor part, a converter part and a main control chip. However, compared with the electromagnetic flowmeter in the prior art, the sensor part in the electromagnetic flowmeter provided in the embodiment of the present application is a four-electrode, including a flow measurement electrode with two electrodes and a conductivity measurement electrode with two electrodes. The flow measurement electrode is used to measure the instantaneous flow of the medium in the pipeline, and while measuring the instantaneous flow through the flow measurement electrode, the conductivity of the medium in the pipeline is measured based on the conductivity measurement electrode. The flow measurement and conductivity measurement of the medium in the pipeline do not affect each other, but jointly determine the actual instantaneous flow of the medium in the pipeline, that is, the actual flow. The converter part of the embodiment of the present application includes a flow signal acquisition circuit and a conductivity signal acquisition circuit, the flow measurement electrode is connected to the flow signal acquisition circuit in the converter part through a wire, and the conductivity measurement electrode is connected to the conductivity signal acquisition circuit in the converter part through a wire. The output end of the flow signal acquisition circuit and the output end of the conductivity signal acquisition circuit are connected to the input end of the main control chip, so that the main control chip receives the voltage value of the output end of the flow signal acquisition circuit and the voltage value of the output end of the conductivity acquisition circuit to indirectly determine the instantaneous flow and conductivity of the medium in the pipeline, thereby determining the actual instantaneous flow in the pipeline based on the obtained instantaneous flow and conductivity, realizing flow compensation, and improving the accuracy of the measurement results when the electromagnetic flowmeter measures the medium.

[0026] Figure 3 1 is a block diagram of a measurement method of a low-conductivity electromagnetic flowmeter provided in an embodiment of the present application. Figure 3 As shown, a measurement method of a low-conductivity electromagnetic flowmeter includes the following steps: Step S100, obtaining a measured flow value of the medium in the pipeline obtained by the flow electrode, and a medium conductivity of the medium in the pipeline obtained by the conductivity electrode.

[0027] The above-mentioned measured flow value refers to a flow value of the medium in the pipeline obtained by the main control chip through the flow measurement electrode when the electromagnetic flowmeter is in normal working condition. The measured flow value refers to the flow value before the flow is compensated. The medium conductivity refers to the conductivity of the medium in the pipeline obtained at the same time as the above-mentioned measured flow value. The above-mentioned measured flow value and medium conductivity refer to the parameters of the same medium in the pipeline at the same time. Among them, the sensor coefficient is stored in the main control chip, and the voltage value multiplied by the sensor coefficient is recorded as the measured flow value. The main control chip can obtain the measured flow value by multiplying the voltage value at the output end of the flow signal acquisition circuit by the sensor coefficient.

[0028] The flow electrode includes a first flow electrode and a second flow electrode, and the conductivity electrode includes a first conductivity electrode and a second conductivity electrode. The first flow electrode, the second flow electrode, the first conductivity electrode and the second conductivity electrode are evenly arranged on the outer wall of the pipeline along the circumference of the pipeline, and are distributed alternately. That is, in a clockwise or counterclockwise direction, they are the first flow electrode, the first conductivity electrode, the second flow electrode and the second conductivity electrode. When the medium fills the pipeline, there is a certain resistance value between the first conductivity electrode and the second conductivity electrode of the sensor part. The conductivity electrodes can be regarded as the two ends of a resistor to be measured, and the pipeline can be regarded as a resistor with a resistance value ranging from 1kΩ to 1MΩ. Figure 4 Schematic diagram of a circuit consisting of a conductivity electrode and a pipeline provided in an embodiment of the present application. Figure 4 As shown, the first conductivity electrode is connected to the power supply through a set resistor, and the second conductivity electrode is grounded. The set resistor is R1, which is a precision resistor. The resistance value of the set resistor is known and stored in the main control chip. The process of obtaining the medium conductivity of the medium in the pipeline obtained by the conductivity electrode includes the following steps: Step S101, obtaining a measured voltage value between a first conductivity electrode and a second conductivity electrode, multiplying the measured voltage value by a set resistance value of a set resistor, and then dividing the measured voltage value by a voltage difference between a power supply voltage of a power supply and the measured voltage value to obtain an electrode resistance formed by the first conductivity electrode and the second conductivity electrode.

[0029] Step S102, obtaining a preset conductivity and resistance calculation relationship, substituting the electrode resistance into the calculation relationship to obtain the medium conductivity of the medium in the pipeline.

[0030] The set resistor and the resistor composed of the first conductivity electrode and the second conductivity electrode are connected in series between the power supply and the ground. The electrode resistance composed of the first conductivity electrode and the second conductivity electrode is obtained according to the resistance voltage division principle. The electrode resistance is thus obtained Among them, V cc is the power supply voltage, V 测 To measure the voltage, R 精 To set the resistance value.

[0031] The above-mentioned preset conductivity and resistance calculation relationship refers to the conductivity corresponding to different resistance values. The preset conductivity and resistance calculation relationship is obtained by the relevant staff of the manufacturer when the electromagnetic flowmeter leaves the factory, and is stored in the main control chip. The preset conductivity and resistance calculation relationship can be obtained by viewing the information stored in the main control chip, and then the electrode resistance obtained in the above step S101 is substituted into this calculation relationship to obtain the medium conductivity of the medium in the pipeline.

[0032] Step S200, determining whether the medium conductivity falls within a preset conductivity compensation range, if not, determining whether the medium conductivity exceeds the preset conductivity compensation range, if not, generating an empty pipe signal indicating that the pipeline is in an empty pipe state.

[0033] Step S300: If the flow rate exceeds the limit, a non-compensation signal is generated to indicate that no flow compensation is required.

[0034] After obtaining the conductivity of the medium in the pipeline, it is necessary to determine the relationship between the medium in the pipeline and the preset conductivity compensation range based on the obtained medium conductivity, so as to decide whether the measured flow value that has been obtained needs to be compensated. After all, when the medium conductivity is too low, it is determined that there is no flow flowing into the pipeline, that is, the pipeline is in an empty pipe state, and the electromagnetic flowmeter is not in a normal working state at this time; when the medium conductivity is too high, compensation is no longer required. The above-mentioned preset conductivity compensation range includes an upper limit value of conductivity compensation and a lower limit value of conductivity compensation, and a conductivity reference value is also set between the upper limit value of conductivity compensation and the lower limit value of conductivity compensation. The conductivity compensation upper limit value and the conductivity reference value can be determined according to the original measurement range of the electromagnetic flowmeter. In this embodiment, the conductivity reference value is set to 1μs / cm, and the conductivity compensation upper limit value is set to 5μs / cm.

[0035] Determining the lower limit value of conductivity compensation includes: obtaining the empty pipe conductivity value of the pipeline in an empty pipe state during the test phase, and a set threshold value, subtracting the empty pipe conductivity value from the conductivity reference value, multiplying the result by the threshold value, and adding the empty pipe conductivity value to obtain the lower limit value of conductivity compensation.

[0036] Before the electromagnetic flowmeter leaves the factory, the relevant staff will conduct tests to obtain the conductivity value under the calibration empty pipe state, that is, the empty pipe conductivity value. And set a threshold, and store the empty pipe conductivity value and threshold in the main control chip. The empty pipe conductivity value and threshold can be obtained by viewing the information stored in the main control chip. Then substitute the empty pipe conductivity value, threshold and conductivity reference value into the conductivity compensation lower limit value = (conductivity reference value-empty pipe conductivity value) × threshold + empty pipe conductivity value to obtain the conductivity compensation lower limit value. For example, the empty pipe conductivity value is 0.1μs / cm, and the set threshold is 50%, then the conductivity compensation lower limit value = (1-0.1) × 50% + 0.1 = 0.55.

[0037] Whether the medium conductivity falls within the preset conductivity compensation range can be determined by comparing the medium conductivity obtained in the above step S100 with the conductivity compensation upper limit value and the conductivity compensation lower limit value of the preset conductivity compensation range. If the medium conductivity is not less than the conductivity compensation lower limit value and not greater than the conductivity compensation upper limit value, then the medium conductivity falls within the preset conductivity compensation range; if the medium conductivity is less than the conductivity compensation lower limit value, or the medium conductivity is greater than the conductivity compensation upper limit value, then the medium conductivity does not fall within the preset conductivity compensation range.

[0038] In the case where the medium conductivity does not fall within the preset conductivity compensation range, it is further determined whether the medium conductivity exceeds the preset conductivity compensation range, that is, it is further determined whether the medium conductivity does not fall within the preset conductivity compensation range because the medium conductivity is less than the conductivity compensation lower limit value or because the medium conductivity is greater than the conductivity compensation upper limit value. If it is because the medium conductivity is less than the conductivity compensation lower limit value, then it is determined that the medium conductivity does not exceed the preset conductivity compensation range. If it is because the medium conductivity is greater than the conductivity compensation upper limit value, then it is determined that the medium conductivity exceeds the preset conductivity compensation range.

[0039] When the conductivity of the medium does not exceed the preset conductivity compensation range, the conductivity of the medium in the pipeline is less than 0.55μs / cm. The main control chip directly determines that there is no flowing medium in the pipeline and the pipeline is in an empty pipe state, that is, an empty pipe signal is generated to indicate that the pipeline is in an empty pipe state. In addition, the main control chip also generates an alarm signal to inform relevant personnel so that they can take corresponding measures in time. The electromagnetic flowmeter will no longer measure the flow until the conductivity of the medium is greater than 0.55μs / cm, and then resume the flow measurement of the medium.

[0040] When the conductivity of the medium exceeds the preset conductivity compensation range, the conductivity of the medium in the pipeline is greater than 5μs / cm. The main control chip determines that the attenuation of the flow signal obtained by the converter part is very small, and flow compensation is no longer required. At this time, an uncompensated signal is generated to indicate that no flow compensation is required, and the measured flow value obtained in the above step S100 is directly determined as the actual flow value of the medium in the pipeline, thereby obtaining an accurate actual flow value of the medium in the pipeline.

[0041] Step S400, if it falls, obtain the flow compensation coefficient, determine the flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain the actual flow value of the medium in the pipeline.

[0042] In the case where the medium conductivity falls within the preset conductivity compensation range, due to the low conductivity of the medium, the main control chip determines that the flow signal obtained by the converter part is attenuated, and the measured flow value obtained in the above step S100 is smaller than the actual flow value, and the flow needs to be compensated. That is, the above step S400 needs to be executed. Figure 5 This is a block diagram of obtaining flow compensation coefficients provided in an embodiment of the present application. Figure 5 As shown, obtaining the flow compensation coefficient includes the following steps: Step S401, obtaining, under a set flow condition, a first flow value measured by the electromagnetic flowmeter when the conductivity is an upper limit value of conductivity compensation, and a second flow value measured when the conductivity is a conductivity reference value.

[0043] Step S402, subtracting the first flow value from the value 1 and dividing it by the set flow value corresponding to the set flow to obtain a first flow compensation ratio.

[0044] Step S403, subtracting the second flow value from the value 1 and dividing it by the set flow value corresponding to the set flow to obtain a second flow compensation ratio.

[0045] Step S404: Divide the compensation ratio difference between the second flow compensation ratio and the first flow compensation ratio by the conductivity compensation difference between the conductivity reference value and the conductivity compensation upper limit value to obtain a flow compensation coefficient.

[0046] When the conductivity is within the preset conductivity compensation range, the loss ratio of flow is linear. The above flow compensation coefficient refers to the percentage required for compensation for each unit increase in conductivity within the preset conductivity compensation range. The flow compensation coefficient is obtained by the manufacturer's relevant personnel during the production of the electromagnetic flowmeter and stored in the main control chip.

[0047] The above-mentioned set flow rate refers to the flow rate given to the medium in the pipeline by the relevant personnel when conducting the test, and the set flow rate value of the set flow rate is known. When the medium adopts this set flow rate, the medium whose flow conductivity in the pipeline is any value between the conductivity reference value and the conductivity compensation upper limit value, obtains the first flow value obtained by the flow electrode at this time from the main control chip; and when the medium adopts this set flow rate, the medium whose flow conductivity in the pipeline is any other value between the conductivity reference value and the conductivity compensation upper limit value, obtains the second flow value obtained by the flow electrode at this time from the main control chip. These two arbitrary values ​​are not the same. It is preferred that when the medium adopts this set flow rate, the flow conductivity in the pipeline is respectively close to the conductivity reference value and close to the conductivity compensation upper limit value. For example, the two values ​​of 1.1 and 4.9. In this embodiment, when the medium adopts this set flow rate, the medium whose flow conductivity in the pipeline is 5μs / cm, obtains the first flow value obtained by the flow electrode at this time from the main control chip. When the medium adopts this set flow rate, the medium with a flow conductivity of 1μs / cm in the pipeline is obtained from the main control chip through the flow electrode. Then substitute the first flow value and the set flow value into And substitute the second flow value and the set flow value into Finally, the first flow compensation ratio, the second flow compensation ratio, the conductivity compensation upper limit value and the conductivity reference value are substituted into In this way, the flow compensation coefficient is obtained. Among them, the flow compensation ratio is linearly related to the conductivity. The conductivity and the flow compensation ratio form a two-variable first-order equation, with the conductivity as the independent variable and the flow compensation ratio as the dependent variable. The flow compensation coefficient is the slope. The flow compensation coefficient is stored in the main control chip of the electromagnetic flowmeter after being obtained by relevant personnel. Therefore, the flow compensation coefficient can be obtained by viewing the information stored in the main control chip.

[0048] After the flow compensation coefficient is obtained, it is also necessary to determine the flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient. The flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient includes the following steps: Step S405, based on the flow compensation coefficient, the conductivity compensation upper limit value and the first flow compensation ratio, or based on the flow compensation coefficient, the conductivity reference value and the second flow compensation ratio, to obtain a flow compensation relationship.

[0049] Step S406: Substitute the medium conductivity into the flow compensation relationship to obtain a flow compensation ratio required to compensate the flow.

[0050] Step S407, dividing the flow measurement value by the difference between the value 1 and the flow compensation ratio, and then subtracting the flow measurement value to obtain the flow compensation value required to compensate the flow.

[0051] The above-mentioned flow compensation relationship refers to a two-variable linear equation formed by conductivity and flow compensation ratio. After the slope of the two-variable linear equation is known, the two-variable linear equation, i.e., the flow compensation relationship, can also be obtained by using a set of parameters in the linear relationship, such as the conductivity compensation upper limit value and the first flow compensation ratio, or the conductivity reference value and the second flow compensation ratio.

[0052] Then, the medium conductivity is used as the independent variable in the flow compensation relationship to substitute into the flow compensation relationship, thereby obtaining the flow compensation ratio that needs to be compensated for the flow. Finally, substitute the flow compensation ratio into In this formula, we get Finally, the flow compensation value is added to the flow measurement value obtained in the above step S100 to obtain the actual flow value of the medium in the pipeline. In this way, by introducing the conductivity electrode, the medium conductivity of the medium in the pipeline is first determined, and then the flow compensation value that needs to be compensated is determined according to the medium conductivity. When it is determined that the flow needs to be compensated, the flow compensation value that needs to be compensated for the flow is indirectly obtained according to the medium conductivity. Finally, the measured flow value that has been initially obtained and has been lost is added to the obtained flow compensation value to obtain the actual flow value that can truly reflect the flow of the medium in the pipeline, so as to improve the accuracy of the measurement results when the electromagnetic flowmeter measures the medium. And on the basis of the electromagnetic flowmeter that originally measures the conductivity of 5μs / cm, only the conductivity electrode and the corresponding converter part need to be added, and the new electromagnetic flowmeter does not need to be replaced to increase the accurate measurement of the flow of the medium at the conductivity compensation lower limit value ~ 5μs / cm conductivity, which can save costs compared to replacing the electromagnetic flowmeter.

[0053] Figure 6 1 is a measurement system framework diagram of a low-conductivity electromagnetic flowmeter provided in an embodiment of the present application. Figure 6 As shown, a measurement system of a low-conductivity electromagnetic flowmeter includes: a flow electrode module, a conductivity electrode module, and a compensation module.

[0054] Among them, the flow electrode module is used to obtain the measured flow value of the medium in the pipeline obtained by the flow electrode. The conductivity electrode module is used to obtain the medium conductivity of the medium in the pipeline obtained by the conductivity electrode. The compensation module is used to determine whether the medium conductivity falls within the preset conductivity compensation range. If not, determine whether the medium conductivity exceeds the preset conductivity compensation range. If not, generate an empty pipe signal indicating that the pipeline is in an empty pipe state; if exceeded, generate a no compensation signal indicating that no flow compensation is required; if it falls, obtain the flow compensation coefficient, determine the flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain the actual flow value of the medium in the pipeline.

[0055] The other functions performed by the above-mentioned flow electrode module, conductivity electrode module and compensation module and the technical details of each function are the same or similar to the corresponding features in the measurement method of a low-conductivity electromagnetic flowmeter described above, so they are not repeated here.

[0056] An embodiment of the present application further provides a computer storage medium on which a computer program is stored. When the computer program is run on a computer, the computer can execute the steps in the measurement method of a low-conductivity electromagnetic flowmeter described above.

[0057] It should be understood that, although the steps in the flowchart of the accompanying drawings are shown in sequence according to the instructions of the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless explicitly stated in this document, the execution of these steps is not strictly limited in order and can be performed in other orders.

[0058] The above description is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A measurement method for a low-conductivity electromagnetic flowmeter, characterized in that: The method comprises: Obtaining a measured flow value of the medium in the pipeline obtained by the flow electrode and a medium conductivity of the medium in the pipeline obtained by the conductivity electrode; Determine whether the medium conductivity falls within a preset conductivity compensation range; if not, determine whether the medium conductivity exceeds the preset conductivity compensation range; if not, generate an empty pipe signal indicating that the pipeline is in an empty pipe state; If it exceeds, a non-compensated signal is generated indicating that no flow compensation is required; If it does, obtain a flow compensation coefficient, determine a flow compensation value that needs to be used to compensate the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain the actual flow value of the medium in the pipeline.

2. The method according to claim 1, characterized in that: The conductivity electrode comprises a first conductivity electrode and a second conductivity electrode, the first conductivity electrode is connected to a power supply via a set resistor, the second conductivity electrode is grounded, and the medium conductivity of the medium in the pipeline obtained by obtaining the conductivity electrode comprises: Obtaining a measured voltage value between the first conductivity electrode and the second conductivity electrode, multiplying the measured voltage value by a set resistance value of the set resistor, and dividing the result by a voltage difference between a power supply voltage of the power supply and the measured voltage value, so as to obtain an electrode resistance formed by the first conductivity electrode and the second conductivity electrode; A preset conductivity-resistance calculation relationship is obtained, and the electrode resistance is substituted into the calculation relationship to obtain the medium conductivity of the medium in the pipeline.

3. The method according to claim 1, characterized in that The preset conductivity compensation range includes a conductivity compensation upper limit value and a conductivity compensation lower limit value, and a conductivity reference value is also provided between the conductivity compensation upper limit value and the conductivity compensation lower limit value. The method further includes: The empty pipe conductivity value of the pipeline in the empty pipe state during the test phase and the set threshold are obtained, the empty pipe conductivity value is subtracted from the conductivity reference value, multiplied by the threshold, and then added to the empty pipe conductivity value to obtain the conductivity compensation lower limit value.

4. The method according to claim 3, characterized in that The obtaining of the flow compensation coefficient comprises: Obtaining, under a set flow rate condition, a first flow rate value measured by the electromagnetic flowmeter when the conductivity is the conductivity compensation upper limit value, and a second flow rate value measured when the conductivity is the conductivity reference value; Subtracting the first flow value from the value 1 and dividing it by the set flow value corresponding to the set flow to obtain a first flow compensation ratio; The second flow rate compensation ratio is obtained by subtracting the second flow rate value from the value 1 and dividing it by the set flow rate value corresponding to the set flow rate; The flow compensation coefficient is obtained by dividing the compensation ratio difference between the second flow compensation ratio and the first flow compensation ratio by the conductivity compensation difference between the conductivity reference value and the conductivity compensation upper limit value.

5. The method according to claim 4, characterized in that The flow compensation value required to compensate the flow rate based on the medium conductivity and the flow compensation coefficient comprises: Based on the flow compensation coefficient, the conductivity compensation upper limit value and the first flow compensation ratio, or based on the flow compensation coefficient, the conductivity reference value and the second flow compensation ratio, a flow compensation relationship is obtained; Substituting the medium conductivity into the flow compensation relationship to obtain a flow compensation ratio required to compensate the flow; The flow measurement value is divided by the difference between the value one and the flow compensation ratio, and then the flow measurement value is subtracted to obtain the flow compensation value required to compensate the flow.

6. The method according to claim 2, characterized in that The flow electrode comprises a first flow electrode and a second flow electrode. The first flow electrode, the second flow electrode, the first conductivity electrode and the second conductivity electrode are evenly arranged on the outer wall of the pipeline along the circumference of the pipeline and are distributed alternately.

7. The method according to claim 1, characterized in that If the medium conductivity does not exceed the preset conductivity compensation range, the method further includes: generating an alarm signal.

8. The method according to claim 1, characterized in that If the medium conductivity exceeds the preset conductivity compensation range, the method further includes: determining the measured flow value as an actual flow value of the medium in the pipeline.

9. A measurement system for a low-conductivity electromagnetic flowmeter, characterized in that: The system comprises: a flow electrode module, a conductivity electrode module and a compensation module; wherein, The flow electrode module is used to obtain the measured flow value of the medium in the pipeline obtained by the flow electrode; The conductivity electrode module is used to obtain the medium conductivity of the medium in the pipeline obtained by the conductivity electrode; The compensation module is used to determine whether the medium conductivity falls within a preset conductivity compensation range. If not, determine whether the medium conductivity exceeds the preset conductivity compensation range. If not, generate an empty pipe signal indicating that the pipeline is in an empty pipe state; if exceeded, generate a no compensation signal indicating that no flow compensation is required; if within, obtain a flow compensation coefficient, determine a flow compensation value that needs to be compensated for the flow based on the medium conductivity and the flow compensation coefficient, and add the flow compensation value to the measured flow value to obtain an actual flow value of the medium in the pipeline.

10. A computer-readable storage medium having a computer program that can be run on a processor stored thereon, characterized in that: When the computer program is executed by the processor, the measurement method of a low-conductivity electromagnetic flowmeter as claimed in any one of claims 1 to 8 is implemented.

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