Sensitive resistor measuring device, sensitive resistor calibration device and sensor

Abstract

The embodiment of the utility model provides a sensitive resistor measuring device, a sensitive resistor calibration device and a sensor, and belongs to the technical field of circuit detection. The sensitive resistor measuring device comprises a reference voltage generating circuit, a resistance bridge and a voltage detection loop, the reference voltage generating circuit comprises a first resistor and a reference power supply chip which are connected in series between a grounding end and a power supply end, and a second resistor and a third resistor which are used for dividing the output of the reference power supply chip; the voltage output by the reference power supply chip is used as the reference voltage generated by the reference voltage generation circuit; the resistance bridge comprises a fourth resistor, a fifth resistor and a sixth resistor with known resistance values and a sensitive resistor, one diagonal of the resistance bridge is connected with reference voltage, and the other diagonal of the resistance bridge is a voltage difference output end of the resistance bridge; and the output voltage after the voltage difference of the resistance bridge is processed by the operational amplifier is used as the resistance measurement feedback of the sensitive resistor. The device can improve the precision of measuring and calibrating the resistance value of the sensitive resistor.

Description

Technical Field

[0001] This utility model relates to the field of circuit testing technology, specifically to a sensitive resistor measuring device, a sensitive resistor calibration device, and a sensor. Background Technology

[0002] Current technology for measuring and calibrating the resistance of sensitive resistors involves outputting a fixed current, for example, within the range of 4~20mA, then detecting the voltage across the sensitive resistor. The equivalent resistance is calculated by dividing the voltage by the current, and a resistance table is then used to calibrate the resistor under different environmental parameters. When using a sensitive resistor to measure environmental parameters, the current environmental parameter value is determined according to the calibrated resistance table.

[0003] However, under current technological conditions, to provide accurate resistance values ​​for measuring and calibrating sensitive resistors, both the accuracy of the output current and the accuracy of the voltage across the sensitive resistor must meet preset requirements to ensure accurate calculation of the equivalent resistance. Deviations in the output current or the voltage across the sensitive resistor will inevitably lead to deviations in the resistance calculation, affecting the accuracy of the calibrated resistance table and consequently the accuracy of the measurement results when measuring environmental parameters of the calibrated sensitive resistor.

[0004] In the process of realizing this invention, the inventors of this utility model application discovered that the above-mentioned defects of the prior art have not yet been resolved. Utility Model Content

[0005] The purpose of this utility model embodiment is to provide a sensitive resistor measuring device that can improve the accuracy of measuring and calibrating the resistance value of a sensitive resistor.

[0006] To achieve the above objectives, this utility model provides a sensitive resistor measuring device, including a reference voltage generation circuit, a resistance bridge, and a voltage detection circuit.

[0007] The reference voltage generation circuit includes: a first resistor and a reference power chip connected in series between the ground terminal and the power supply terminal; and a second resistor and a third resistor used to divide the output of the reference power chip.

[0008] The voltage output by the reference power supply chip is used as the reference voltage generated by the reference voltage generation circuit.

[0009] The resistor bridge includes a fourth resistor, a fifth resistor, a sixth resistor with known resistance values, and a sensitive resistor. One diagonal of the resistor bridge is connected to the reference voltage, and the other diagonal is the voltage difference output terminal of the resistor bridge.

[0010] The voltage detection circuit includes: a seventh resistor connected in series between one of the voltage difference output terminals and the non-inverting input terminal of the operational amplifier; and an eighth resistor connected in series between the other of the voltage difference output terminals and the inverting input terminal of the operational amplifier; and

[0011] The voltage difference of the resistance bridge, after being processed by the operational amplifier, is used as the output voltage for the resistance measurement feedback of the sensitive resistor.

[0012] Optionally, the resistance accuracy of the first resistor, second resistor, third resistor, fourth resistor, fifth resistor, sixth resistor, and eighth resistor is 0.1%.

[0013] Furthermore, the sensitive resistor measuring device also includes a first capacitor connected between the reference voltage and the ground terminal to filter out fluctuations in the reference voltage.

[0014] Furthermore, the sensitive resistor measuring device also includes an RC filter circuit connected between the output terminal of the operational amplifier and the inverting input terminal of the operational amplifier to filter out the high-frequency components in the output voltage of the operational amplifier.

[0015] Optionally, the reference power supply chip can be a TL or LM series chip.

[0016] Optionally, the sensitive resistor is a resistive component that is sensitive to one of the following: light intensity, pressure, temperature, humidity, magnetic field strength, and gas concentration.

[0017] On the other hand, this utility model embodiment provides a sensitive resistor calibration device, including: a controller and the sensitive resistor measuring device of this application, wherein the controller calibrates the resistance value of the sensitive resistor under different environmental parameters based on the resistance value measurement feedback output by the operational amplifier, and the environmental parameters are the physical parameters that the sensitive resistor is sensitive to.

[0018] On the other hand, this utility model embodiment provides a sensor for measuring environmental parameters such as light intensity, pressure, temperature, humidity, magnetic field strength, and gas concentration.

[0019] Including the sensitive resistor measuring device of this application;

[0020] The sensitive resistor is a pre-calibrated sensitive resistor, which is sensitive to environmental parameters; and

[0021] Based on the resistance measurement feedback from the operational amplifier output, the environmental parameters of the sensitive resistor in the current scenario are determined.

[0022] Optionally, the sensor also includes an alarm that emits an alarm signal when environmental parameters exceed a preset threshold.

[0023] Optionally, the type and specifications of the sensitive resistor can be selected based on the numerical range of the environmental parameter to be measured.

[0024] Through the above technical solution, the first resistor is a pull-up resistor, which raises the voltage obtained by the reference power chip. The second and third resistors are used for voltage division, so that the output voltage of the reference power chip is a stable reference voltage. The fourth, fifth, and sixth resistors with known resistance values ​​and the sensitive resistor form a resistor bridge. One diagonal of the resistor bridge is connected to the reference voltage, and the other diagonal is the voltage difference output terminal of the resistor bridge. The output voltage of the voltage difference of the resistor bridge after processing by the operational amplifier is used as the resistance value measurement feedback of the sensitive resistor. That is, the stable reference voltage powers the bridge, replacing the fixed current required in the prior art. At the same time, the output voltage of the voltage difference output by the bridge after processing by the operational amplifier can directly feed back the resistance value change of the sensitive resistor, replacing the requirement of directly measuring the voltage across the sensitive resistor in the prior art, reducing measurement errors, and improving the accuracy of measuring and calibrating the resistance value of the sensitive resistor.

[0025] Other features and advantages of this utility model embodiment will be described in detail in the following detailed description section. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0027] Figure 1 This is a circuit diagram of an embodiment of the sensitive resistor measuring device of this utility model. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0029] In the description of this specification, the terms "comprising," "including," "having," and "containing" are open-ended terms, meaning that they include but are not limited to. The terms "an embodiment," "a specific embodiment," "some embodiments," and "for example," etc., refer to specific features, structures, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. The order of steps involved in the various embodiments is used to illustrate the implementation of this application, and the order of steps is not limited and can be adjusted appropriately as needed.

[0030] This utility model embodiment provides a sensitive resistor measuring device. Figure 1 The circuit layout of the sensitive resistor measuring device is shown, including a reference voltage generation circuit, a resistor bridge, and a voltage detection circuit. The reference voltage generation circuit includes: a first resistor R1 connected in series between the ground terminal and the power supply terminal, and a reference power supply chip TL431BCLP; a second resistor R2 and a third resistor R3 used to divide the output of the reference power supply chip TL431BCLP; the voltage Vref output by the reference power supply chip TL431BCLP serves as the reference voltage generated by the reference voltage generation circuit. The resistor bridge includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 with known resistance values, and a sensitive resistor Rpt. One diagonal of the resistor bridge is connected to the reference voltage Vref, and the other diagonal is the voltage difference output terminal of the resistor bridge. The voltage detection circuit includes: a seventh resistor R7 connected in series between one of the voltage difference output terminals and the non-inverting input terminal of the operational amplifier; and an eighth resistor R8 connected in series between the other voltage difference output terminal and the inverting input terminal of the operational amplifier. The output voltage of the voltage difference of the resistor bridge after processing by the operational amplifier serves as the resistance value measurement feedback of the sensitive resistor Rpt.

[0031] In this embodiment, in order to filter out fluctuations in the reference voltage Vref, a first capacitor C1 is connected between the reference voltage and the ground terminal.

[0032] In this embodiment, to filter out the high-frequency components in the operational amplifier's output voltage, an RC filter circuit is connected between the operational amplifier's output terminal and its inverting input terminal. Figure 1 The resistor R9 and capacitor C2 are connected in parallel.

[0033] In this embodiment, the sensitive resistor Rpt is PT100, but it is not limited to this. The sensitive resistor can be a resistive element that is sensitive to one of the following: light intensity, pressure, temperature, humidity, magnetic field strength, and gas concentration.

[0034] In this embodiment, a high-precision reference power supply chip TL431BCLP is used, with an external pull-up resistor R1 connected to a 12V power supply, and voltage divider resistors R2 and R3 providing precise voltage division for the precision resistor, generating a reference voltage Vref of 3.5V. R4-R6 in the resistor bridge are integrated resistors to reduce resistance drift caused by temperature. R4 and R5 form one bridge arm, and the resistance values ​​of R4-R5 are both 2kΩ. R6 and Rpt form the other bridge arm. Since Rpt in this embodiment is a PT100 temperature-sensing resistor, its resistance range is 80.1Ω~175.8Ω within the range of -50℃ to 200℃. Therefore, the resistance value of R6 is equivalent to the starting value of the PT100's measurement range. When the PT100 temperature-sensing resistor... Figure 1 When the resistance of Rpt changes with the ambient temperature, the different ratios of the bridge arm resistances of R6 and Rpt generate a voltage difference. The voltage detection circuit processes this voltage difference to provide feedback on the resistance offset of PT100.

[0035] In addition, this embodiment also uses resistors R7, R8, and R10 to limit the current and prevent damage to the components in the circuit. Technicians can determine whether to use resistors R7, R8, and R10, as well as the resistance values ​​of resistors R7, R8, and R10, based on the withstand voltage parameters of the components in the circuit.

[0036] It should be noted that in this embodiment, the resistors used are all high-precision resistors with a resistance accuracy of 0.1%. Technicians can choose the accuracy of the resistor according to the actual needs of the measurement, and this application does not impose any restrictions.

[0037] It should also be noted that, Figure 1 The resistance and capacitance values, as well as the reference power supply chip model, were selected for the purposes of this embodiment and are not intended to limit this application.

[0038] Compared with the prior art, the technical advantages of this embodiment are as follows: a stable reference voltage is constructed by using a high-precision reference power chip and a precision resistor. The stable reference voltage powers the bridge circuit, replacing the fixed current required in the prior art. The output voltage of the bridge circuit, after being processed by an operational amplifier, can directly reflect the resistance change of the sensitive resistor, replacing the requirement in the prior art to directly measure the voltage across the sensitive resistor, reducing measurement errors and improving the accuracy of measuring and calibrating the resistance value of the sensitive resistor.

[0039] This utility model provides a temperature measurement calibration device and a sensitive resistor calibration device, including: a controller and the sensitive resistor measuring device of this application, wherein the controller calibrates the resistance value of the sensitive resistor under different environmental parameters based on the resistance value measurement feedback output by the operational amplifier, and the environmental parameters are the physical parameters that the sensitive resistor is sensitive to.

[0040] This utility model provides a sensor for measuring environmental parameters such as light intensity, pressure, temperature, humidity, magnetic field strength, and gas concentration, including the sensitive resistor measuring device of this application; the sensitive resistor is a pre-calibrated sensitive resistor, wherein the sensitive resistor is sensitive to environmental parameters; the environmental parameters of the sensitive resistor in the current scene are determined based on the resistance measurement feedback output by the operational amplifier.

[0041] In some embodiments, the sensor also includes an alarm that emits an alarm signal when environmental parameters exceed a preset threshold.

[0042] In some embodiments, the type and specifications of the sensitive resistor are selected based on the numerical range of the environmental parameter to be measured.

[0043] In some embodiments, the sensor further includes a communication device for transmitting alarm signals and / or monitored environmental parameters.

[0044] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0045] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A sensitive resistor measuring device, characterized in that, This includes a reference voltage generation circuit, a resistor bridge, and a voltage detection circuit. The reference voltage generation circuit includes: a first resistor and a reference power chip connected in series between a ground terminal and a power supply terminal; and a second resistor and a third resistor used to divide the output of the reference power chip. The voltage output by the reference power supply chip is used as the reference voltage generated by the reference voltage generation circuit. The resistor bridge includes a fourth resistor, a fifth resistor, a sixth resistor with known resistance values, and the sensitive resistor. One diagonal of the resistor bridge is connected to the reference voltage, and the other diagonal is the voltage difference output terminal of the resistor bridge. The voltage detection circuit includes: a seventh resistor connected in series between one of the voltage difference output terminals and the non-inverting input terminal of the operational amplifier; and an eighth resistor connected in series between the other of the voltage difference output terminals and the inverting input terminal of the operational amplifier; and The voltage difference of the resistor bridge, after being processed by the operational amplifier, is used as the output voltage for the resistance measurement feedback of the sensitive resistor.

2. The sensitive resistor measuring device according to claim 1, characterized in that, The resistance accuracy of the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, the sixth resistor, and the eighth resistor is 0.1%.

3. The sensitive resistor measuring device according to claim 1, characterized in that, It also includes a first capacitor, connected between the reference voltage and the ground terminal, for filtering out fluctuations in the reference voltage.

4. The sensitive resistor measuring device according to claim 1, characterized in that, It also includes an RC filter circuit, which is connected between the output terminal of the operational amplifier and the inverting input terminal of the operational amplifier to filter out the high-frequency components in the output voltage of the operational amplifier.

5. The sensitive resistor measuring device according to claim 1, characterized in that, The reference power supply chip is a TL or LM series chip.

6. The sensitive resistor measuring device according to any one of claims 1 to 5, characterized in that, The sensitive resistor is a resistive component that is sensitive to one of the following: light intensity, pressure, temperature, humidity, magnetic field strength, and gas concentration.

7. A sensitive resistor calibration device, characterized in that, include: The controller and the sensitive resistor measuring device as described in any one of claims 1 to 6, The controller calibrates the resistance value of the sensitive resistor under different environmental parameters based on the resistance measurement feedback from the operational amplifier output, wherein the environmental parameters are the physical parameters that the sensitive resistor is sensitive to.

8. A sensor for measuring an environmental parameter selected from one of light intensity, pressure, temperature, humidity, magnetic field strength, and gas concentration, characterized in that, Includes the sensitive resistor measuring device as described in any one of claims 1 to 6; The sensitive resistor is a calibrated sensitive resistor, wherein the sensitive resistor is sensitive to the environmental parameter; and Based on the resistance measurement feedback from the operational amplifier output, the environmental parameters of the sensitive resistor in the current scenario are determined.

9. The sensor according to claim 8, characterized in that, It also includes an alarm that issues an alarm signal when the environmental parameters exceed a preset threshold.

10. The sensor according to claim 8, characterized in that, Select the type and specifications of the sensitive resistor based on the numerical range of the environmental parameters to be measured.

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