A method and system for improving the accuracy of a differential resistance sensor

Abstract

The application discloses a kind of measurement method and system for improving the precision of differential resistance sensor, comprising: control constant current flows through reference resistance R S , differential resistance sensor resistance R1 and differential resistance sensor resistance R2;The voltage generated on reference resistance R S , differential resistance sensor resistance R1 and differential resistance sensor resistance R2 is introduced into instrument amplifier, and AD code value AD S , AD code value AD1 and AD code value AD2 are obtained using ADC converter;Using AD code value AD S , AD code value AD1 and AD code value AD2 calculate measurement parameter Z′;The measurement parameter Z′ is the difference between differential resistance sensor resistance R1 and differential resistance sensor resistance R2 is the sum of differential resistance sensor resistance R1 and differential resistance sensor resistance R2;Without changing the structure of existing differential resistance sensor, the sensitivity of the sensor is improved, and the linearity of the sensor is improved.

Description

Technical Field

[0001] This invention belongs to the field of differential resistive sensors, and specifically relates to a measurement method and system for improving the accuracy of differential resistive sensors. Background Technology

[0002] Differential resistance sensors are a widely used and important type of monitoring instrument in the field of dam safety monitoring. Differential resistance instruments are widely used in China due to their good moisture resistance, high long-term measurement stability and reliability, and ability to measure temperature. By measuring the resistance ratio of their internal differential resistors, they can be used to measure the stress, strain, cracks, and seepage pressure of concrete. Furthermore, by measuring changes in the resistance value itself, changes in the ambient temperature can also be measured.

[0003] The invention patent with patent publication number CN113280837A discloses a circuit and method for improving the sensitivity of a differential resistive sensor; it requires the addition of two differential resistors, making the structure particularly complex and difficult to manufacture. This patent requires the addition of differential resistors, which not only increases the difficulty of production and the production cost, but also makes it difficult to install on site; it also causes a sharp decrease in repeatability and hysteresis. Summary of the Invention

[0004] The purpose of this invention is to provide a measurement method and system for improving the accuracy of differential resistance sensors. Without changing the existing structure of differential resistance sensors, this invention improves the sensitivity of such sensors and also enhances their linearity.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] The first aspect of this invention provides a measurement method for improving the accuracy of a differential resistance sensor, comprising:

[0007] A constant current is introduced by a constant current source circuit, controlling the flow of the constant current through the reference resistor R. S , Differential resistance sensor resistor R1 and differential resistance sensor resistor R2;

[0008] The reference resistor R S The voltage generated is introduced into an instrumentation amplifier, and the amplified voltage is then used by an ADC converter to obtain the reference resistor R. S AD code value S ;

[0009] The voltages generated on the differential resistive sensor resistors R1 and R2 are introduced into the instrumentation amplifier. The voltages amplified by the instrumentation amplifier are then used with an ADC converter to obtain the AD code values ​​AD1 and AD2 of the differential resistive sensor resistors R1 and R2.

[0010] Using AD code value S The measurement parameter Z′ is calculated using the AD code values ​​AD1 and AD code values ​​AD2; the measurement parameter Z′ is the difference between the differential resistance sensor R1 and the differential resistance sensor R2, and the sum of the differential resistance sensor R1 and the differential resistance sensor R2.

[0011] Preferably, the AD code value is used. S The methods for calculating the measurement parameter Z′ using AD code values ​​AD1 and AD code values ​​AD2 include:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] In the formula, I0 represents the constant current output by the constant current source; U0 represents the AD voltage reference value.

[0019] Preferably, the reference resistor R is obtained through a MUX multiplexer. S The voltage generated across resistors R1 and R2 of the differential resistor sensor.

[0020] A second aspect of the present invention provides a measurement system for improving the accuracy of a differential resistance sensor, comprising a constant current source and a reference resistor R. S The system includes a MUX multiplexer, an instrumentation amplifier, an ADC converter, and an MCU processor; the differential resistance sensor has differential resistance sensor resistors R1 and R2; the cathode of the constant current source is grounded; the anode of the constant current source is sequentially connected to a reference resistor R. S The differential resistance sensor resistors R1 and R2 are grounded; the MUX multiplexer is used to obtain the reference resistor R. S The voltage generated across resistors R1 and R2 of the differential resistor sensor; the MUX multiplexer, instrumentation amplifier, ADC converter, and microcontroller unit (MCU) are electrically connected in sequence;

[0021] The voltage amplified by the instrumentation amplifier is used to obtain the reference resistor R via an ADC converter. S AD code valueS The differential resistance sensor resistor R1 has an AD code value AD1, and the differential resistance sensor resistor R2 has an AD code value AD2; the microcontroller unit (MCU) uses the AD code value AD1. S The measurement parameter Z′ is calculated using the AD code values ​​AD1 and AD code values ​​AD2; the measurement parameter Z′ is the difference between the differential resistance sensor R1 and the differential resistance sensor R2, and the sum of the differential resistance sensor R1 and the differential resistance sensor R2.

[0022] Preferably, a constant current of 2mA is introduced through a constant current source circuit.

[0023] Preferably, the reference resistor RS is set to 50Ω.

[0024] Preferably, the ADC converter is a high-precision ADC converter.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention utilizes the AD code value AD S The measurement parameter Z′ is calculated using AD code values ​​AD1 and AD code values ​​AD2; the measurement parameter Z′ is the ratio of the difference between the differential resistance sensor R1 and the differential resistance sensor R2 to the sum of the differential resistance sensor R1 and the differential resistance sensor R2. This invention can significantly improve the sensitivity of this type of sensor without increasing the number of cores in the lead wire, without increasing the original cost, and without increasing the complexity of the measurement circuit or the difficulty of circuit design. It also improves the linearity and overall error of the sensor. Attached Figure Description

[0027] Figure 1 This is a structural diagram of the differential resistance sensor provided by the present invention;

[0028] Figure 2 This is a structural diagram of a measuring device for improving the accuracy of a differential resistance sensor provided by the present invention.

[0029] In the diagram: 1 First steel wire, 2 Second steel wire, 3 Support rod A, 4 Support rod B. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0031] like Figure 1As shown, the differential resistance sensor includes a support rod A3 and a support rod B4 arranged parallel to each other; a first steel wire 1 and a second steel wire 2 are provided between the support rod A3 and the support rod B4; one end of the first steel wire 1 is connected to the support rod A3, and the other end of the first steel wire 2 is connected to the support rod B4; both ends of the second steel wire 2 are connected to the support rod A3 and the support rod B4 respectively; the first steel wire 1 and the second steel wire 2 are arranged crosswise; the resistance of the first steel wire 1 is set as the differential resistance sensor resistance R1, and the resistance of the second steel wire 2 is set as the differential resistance sensor resistance R2.

[0032] Example 1

[0033] This embodiment provides a measurement method for improving the accuracy of differential resistance sensors, including:

[0034] A constant current is introduced by a constant current source circuit, controlling the flow of the constant current through the reference resistor R. S Differential resistance sensor resistors R1 and R2; reference resistor R is obtained through a MUX multiplexer. S The voltage generated across resistor R1 and resistor R2 of the differential resistance sensor;

[0035] The reference resistor R S The voltage generated is introduced into an instrumentation amplifier, and the amplified voltage is then used by an ADC converter to obtain the reference resistor R. S AD code value S ;

[0036] The voltages generated on the differential resistive sensor resistors R1 and R2 are introduced into the instrumentation amplifier. The voltages amplified by the instrumentation amplifier are then used with an ADC converter to obtain the AD code values ​​AD1 and AD2 of the differential resistive sensor resistors R1 and R2.

[0037] Using AD code value S The measurement parameter Z′ is calculated using AD code values ​​AD1 and AD code values ​​AD2.

[0038] Using AD code value S The methods for calculating the measurement parameter Z′ using AD code values ​​AD1 and AD code values ​​AD2 include:

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] In the formula, I0 represents the constant current output by the constant current source; U0 represents the AD voltage reference value; the measurement parameter Z′ is the difference between the differential resistance sensor R1 and the differential resistance sensor R2, and the sum of the differential resistance sensor R1 and the differential resistance sensor R2.

[0046] During measurement, the ratio of the difference between the two differential resistors to the sum of their resistances is used. This corresponds to the change in external physical quantities experienced by the differential resistance sensor. Without loss of generality, assuming that when the sensor is subjected to pressure, its resistance changes by ΔR, R1 becomes R1+ΔR, and R2 becomes R2-ΔR, then... at this time, It corresponds to the external physical quantity received by the sensor.

[0047] A comparative experiment was conducted between the measurement method of this embodiment and the original measurement method. The same instrument was used to perform measurements using both methods. Table 1 shows the data obtained using the conventional measurement method, and Table 2 shows the data obtained using the measurement method of this embodiment. It can be seen from the data in the two tables that the measurement method of this invention improves all indicators compared with the conventional measurement method.

[0048] Table 1 shows the data obtained using conventional measurement methods;

[0049]

[0050] Table 2 shows the data obtained using the measurement method of this embodiment;

[0051]

[0052] As shown in Table 3, comparing the measurement method of this embodiment with the conventional measurement method, the full-scale output of the differential resistance sensor increased from 577.83 to 2879.64, the minimum reading increased from 2.77 to 0.56, an improvement of nearly 5 times, the nonlinearity error increased from 0.68% to 0.10%, and the basic error increased from 0.70% to 0.15%. In summary, the measurement method of this invention not only improves the sensitivity of the differential resistance sensor but also enhances the various technical specifications of the instrument.

[0053] Table 3 is a data comparison table between the measurement method of this embodiment and the conventional measurement method;

[0054] Conventional measurement methods Measurement method in this embodiment Full-scale output 577.83 2879.64 Minimum reading (με / (0.01%)) 2.77 0.56 Repeatability error (%FS) 0.12 0.10 Hysteresis error (%FS) 0.12 0.05 Nonlinear error (%FS) 0.68 0.10 Basic error (%FS) 0.70 0.15

[0055] Example 2

[0056] like Figure 2 As shown, this embodiment discloses a measurement system for improving the accuracy of a differential resistance sensor, including a constant current source and a reference resistor R. S The system includes a MUX multiplexer, instrumentation amplifier, ADC converter, and MCU processor; the differential resistor sensor has differential resistor R1 and differential resistor R2; a constant current of 2mA is introduced through a constant current source circuit.

[0057] The cathode of the constant current source is grounded; the anode of the constant current source is connected in sequence to a reference resistor R. S The differential resistance sensor resistors R1 and R2 are grounded; the reference resistor R... S The resistance is set to 50Ω; the MUX multiplexer is used to obtain the reference resistance R. S The voltage generated across resistors R1 and R2 of the differential resistor sensor; the MUX multiplexer, instrumentation amplifier, ADC converter, and microcontroller unit (MCU) are electrically connected in sequence;

[0058] The voltage amplified by the instrumentation amplifier is used to obtain the reference resistor R via an ADC converter. S AD code value S The AD code values ​​of resistor R1 and R2 in the differential resistor sensor are AD1 and AD2, respectively; the ADC converter is a high-precision ADC converter.

[0059] The microcontroller unit (MCU) utilizes the AD code value. S The measurement parameter Z′ is calculated using the AD code values ​​AD1 and AD code values ​​AD2; the measurement parameter Z′ is the difference between the differential resistance sensor R1 and the differential resistance sensor R2, and the sum of the differential resistance sensor R1 and the differential resistance sensor R2.

[0060] The ratio of the difference between the two differential resistors to the sum of their resistances. This corresponds to the change in external physical quantities experienced by the differential resistance sensor. Without loss of generality, assuming that when the sensor is subjected to pressure, its resistance changes by ΔR, R1 becomes R1+ΔR, and R2 becomes R2-ΔR, then... at this time, It corresponds to the external physical quantity received by the sensor.

[0061] This implementation can significantly improve the sensitivity of this type of sensor without increasing the number of cores in the lead wire, without increasing the original cost, and without increasing the complexity of the measurement circuit or the difficulty of circuit design. It also improves the linearity and overall error of the sensor.

[0062] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0063] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0064] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0065] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A measurement method for improving the accuracy of a differential resistance sensor, characterized in that, include: A constant current is introduced by a constant current source circuit, controlling the flow of the constant current through the reference resistor R. S , Differential resistance sensor resistor R1 and differential resistance sensor resistor R2; The reference resistor R S The voltage generated is introduced into an instrumentation amplifier, and the amplified voltage is then used by an ADC converter to obtain the reference resistor R. S AD code value S ; The voltages generated on the differential resistive sensor resistors R1 and R2 are introduced into the instrumentation amplifier. The voltages amplified by the instrumentation amplifier are then used with an ADC converter to obtain the AD code values ​​AD1 and AD2 of the differential resistive sensor resistors R1 and R2. Using AD code value S The measurement parameter Z′ is calculated using the AD code values ​​AD1 and AD code values ​​AD2; the measurement parameter Z′ is the difference between the differential resistance sensor R1 and the differential resistance sensor R2, and the sum of the differential resistance sensor R1 and the differential resistance sensor R2.

2. The measurement method for improving the accuracy of a differential resistance sensor according to claim 1, characterized in that, Using AD code value S The methods for calculating the measurement parameter Z′ using AD code values ​​AD1 and AD code values ​​AD2 include: In the formula, I0 represents the constant current output by the constant current source; U0 represents the AD voltage reference value.

3. The measurement method for improving the accuracy of a differential resistance sensor according to claim 1, characterized in that, The reference resistor R is obtained through the MUX multiplexer. S The voltage generated across resistors R1 and R2 of the differential resistor sensor.

4. A measurement system for improving the accuracy of differential resistance sensors, characterized in that, Including constant current source, reference resistor R S The system includes a MUX multiplexer, an instrumentation amplifier, an ADC converter, and an MCU processor; the differential resistance sensor has differential resistance sensor resistors R1 and R2; the cathode of the constant current source is grounded; the anode of the constant current source is sequentially connected to a reference resistor R. S The differential resistance sensor resistors R1 and R2 are grounded; the MUX multiplexer is used to obtain the reference resistor R. S The voltage generated across resistors R1 and R2 of the differential resistor sensor; the MUX multiplexer, instrumentation amplifier, ADC converter, and microcontroller unit (MCU) are electrically connected in sequence; The voltage amplified by the instrumentation amplifier is used to obtain the reference resistor R via an ADC converter. S AD code value S The differential resistance sensor resistor R1 has an AD code value AD1, and the differential resistance sensor resistor R2 has an AD code value AD2; the microcontroller unit (MCU) uses the AD code value AD1. S The measurement parameter Z′ is calculated using the AD code values ​​AD1 and AD code values ​​AD2; the measurement parameter Z′ is the difference between the differential resistance sensor R1 and the differential resistance sensor R2, and the sum of the differential resistance sensor R1 and the differential resistance sensor R2.

5. A measurement system for improving the accuracy of a differential resistance sensor according to claim 4, characterized in that, A constant current of 2mA is introduced through a constant current source circuit.

6. A measurement system for improving the accuracy of a differential resistance sensor according to claim 4, characterized in that, The reference resistor RS is set to 50Ω.

7. A measurement system for improving the accuracy of a differential resistance sensor according to claim 4, characterized in that, The ADC converter is a high-precision ADC converter.

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