CN213455838U - Wireless vibration measurement sensor - Google Patents
Wireless vibration measurement sensor Download PDFInfo
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- CN213455838U CN213455838U CN202022442702.9U CN202022442702U CN213455838U CN 213455838 U CN213455838 U CN 213455838U CN 202022442702 U CN202022442702 U CN 202022442702U CN 213455838 U CN213455838 U CN 213455838U
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- 238000005259 measurement Methods 0.000 title claims abstract description 20
- 238000004891 communication Methods 0.000 claims abstract description 16
- QVFWZNCVPCJQOP-UHFFFAOYSA-N chloralodol Chemical compound CC(O)(C)CC(C)OC(O)C(Cl)(Cl)Cl QVFWZNCVPCJQOP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000003990 capacitor Substances 0.000 claims description 37
- 230000003321 amplification Effects 0.000 claims description 21
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 21
- 230000001629 suppression Effects 0.000 abstract description 2
- 238000004088 simulation Methods 0.000 abstract 1
- 238000001914 filtration Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000009966 trimming Methods 0.000 description 1
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Abstract
The utility model provides a wireless vibration measurement sensor, including vibration sensor, Lora wireless communication module, still include differential amplifier circuit, low pass filter circuit and band pass filter circuit, vibration sensor's output is through differential amplifier circuit, low pass filter circuit and band pass filter circuit connection Lora wireless communication module's simulation input in proper order. The utility model discloses a differential amplifier circuit suppresses the common mode interference that multistage operational amplifier structure caused, filters high frequency noise through low pass filter circuit and disturbs, through band pass filter circuit suppression low frequency noise, very big improvement vibration signal's measurement accuracy.
Description
Technical Field
The utility model relates to a wireless vibration measurement technical field especially relates to a wireless vibration measurement sensor.
Background
The vibration characteristics of high-flexibility building structures, large-span bridges, dams and the like are important parameters for evaluating the structural damage and the bearing capacity of the high-flexibility building structures, and therefore accurate detection of vibration signals is the key for determining the quality of structural health monitoring and evaluation. The wireless vibration measurement sensor is widely applied to vibration monitoring of building structures, large-span bridges, dams and the like, and collected vibration signals can be transmitted in a wireless communication mode.
Because the vibration signal is often very weak, the vibration signal must be subjected to high-gain amplification, low-pass filtering and other processing so as to meet the requirement of subsequent AD sampling measurement. The most effective way to achieve high gain is to select a multi-stage operational amplifier structure for the circuit, and the common mode interference signal is enhanced while the gain is increased by the structure, so that the measurement accuracy of the vibration signal is reduced.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a wireless vibration measurement sensor to solve the problem that common mode interference has reduced vibration signal measurement accuracy among the traditional wireless vibration measurement sensor.
The technical scheme of the utility model is realized like this: a wireless vibration measurement sensor comprises a vibration sensor, a Lora wireless communication module, a differential amplification circuit, a low-pass filter circuit and a band-pass filter circuit;
the output end of the vibration sensor is connected with the analog input end of the Lora wireless communication module through the differential amplification circuit, the low-pass filter circuit and the band-pass filter circuit in sequence.
Optionally, the vibration sensor is model 941B.
Optionally, the differential amplifying circuit includes operational amplifiers U1-U3, resistors R1-R6, and a variable resistor R7;
the output end of the vibration sensor is respectively connected with the non-inverting input ends of an operational amplifier U1 and an operational amplifier U2, the inverting input end of the operational amplifier U1 is connected with the inverting input end of the operational amplifier U2 through a variable resistor R7, the output end of the operational amplifier U1 is connected with the inverting input end of the operational amplifier U1 through a resistor R1, the output end of the operational amplifier U2 is connected with the inverting input end of the operational amplifier U2 through a resistor R2, the output end of the operational amplifier U1 sequentially passes through a resistor R3, the resistor R4 is connected with the output end of the operational amplifier U3, the common end of the resistor R3 and the resistor R4 is connected with the non-inverting input end of the operational amplifier U3, the output end of the operational amplifier U2 is further grounded through a resistor R5 and a resistor R6 in sequence, the common end of the resistor R5 and the resistor R6 is connected with the inverting input end of the operational amplifier U3, and the output end of the operational amplifier U3 is further connected with the input end of the low-pass filter circuit.
Optionally, the differential amplifier circuit further includes variable resistors R8 to R9, a common terminal of the resistor R3 and the resistor R4 is further grounded through a variable resistor R8, and a common terminal of the resistor R5 and the resistor R6 is further grounded through a variable resistor R9.
Optionally, the low-pass filter circuit includes an operational amplifier U4, resistors R9-R11, and capacitors C1-C3;
the output end of the differential amplification circuit is connected with the input end of the band-pass filter circuit through a resistor R9, the common end of the resistor R9 and the input end of the band-pass filter circuit is respectively connected with the inverting input end of an operational amplifier U4 through a capacitor C1 and the output end of an operational amplifier U4 through a capacitor C2, the output end of an amplifier U4 is sequentially grounded through a resistor R11 and a capacitor C3, the common end of a resistor R11 and the capacitor C3 is connected with the inverting input end of the operational amplifier U4 through a resistor R10, and the non-inverting input end of the operational amplifier U4 is grounded.
Optionally, the band-pass filter circuit includes operational amplifiers U5-U6, resistors R12-R19, and capacitors C4-C7;
the output end of the low-pass filter circuit is sequentially connected with the inverting input end of an operational amplifier U5 through a capacitor C4 and a resistor R12, the non-inverting input end of the operational amplifier U5 is connected with a power supply VCC through a resistor R14, the non-inverting input end of the operational amplifier U5 is grounded through a resistor R15 and a capacitor C5 which are connected in parallel, and the output end of the operational amplifier U5 is connected with the inverting input end of the operational amplifier U5 through a resistor R13;
the output end of the operational amplifier U5 is further connected with the inverting input end of the operational amplifier U6 through a capacitor C6 and a resistor R16 in sequence, the non-inverting input end of the operational amplifier U6 is connected with a power supply VCC through a resistor R18, the non-inverting input end of the operational amplifier U6 is further grounded through a resistor R19 and a capacitor C7 which are connected in parallel, the output end of the operational amplifier U6 is connected with the inverting input end of the operational amplifier U6 through a resistor R17, and the output end of the operational amplifier U6 is further connected with the analog input end of the Lora wireless communication module.
The utility model discloses a wireless vibration measurement sensor has following beneficial effect for prior art:
(1) common mode interference caused by a multi-stage operational amplifier structure is suppressed through a differential amplification circuit, high-frequency noise interference is filtered through a low-pass filter circuit, low-frequency noise is suppressed through a band-pass filter circuit, and the measurement accuracy of a vibration signal is greatly improved;
(2) the operational amplifier in the low-pass filter circuit is isolated from the main signal channel through the capacitor C1 and the capacitor C2, and the temperature drift voltage signal, the direct current offset and the direct current drift signal of the operational amplifier are not superposed in the main signal channel, so that the aim of inhibiting the temperature drift, the direct current offset and the direct current drift is fulfilled, the filtering performance of the low-pass filter circuit is improved, and the measuring precision of the vibration signal is further improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a block diagram of the wireless vibration measurement sensor of the present invention;
fig. 2 is a circuit diagram of a differential amplifier circuit according to the present invention;
fig. 3 is a circuit diagram of the low-pass filter circuit of the present invention;
fig. 4 is a circuit diagram of the bandpass filter circuit of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.
As shown in fig. 1, the wireless vibration measurement sensor of the present embodiment includes a vibration sensor, a Lora wireless communication module, a differential amplifier circuit, a low-pass filter circuit, and a band-pass filter circuit. The output end of the vibration sensor is connected with the analog input end of the Lora wireless communication module through the differential amplification circuit, the low-pass filter circuit and the band-pass filter circuit in sequence.
The Lora wireless communication module integrates a Lora communication function and a control function, and can refer to a traditional circuit, and the vibration sensor is used for detecting a vibration signal of a target object; the differential amplification circuit is used for carrying out primary amplification on the output signal of the vibration sensor and extracting a useful vibration signal; the differential amplification circuit amplifies useful signals, meanwhile, various mixed noise interference signals are amplified with the same effect, and the low-pass filter circuit is used for filtering the signals amplified by the differential amplification circuit to realize noise signal suppression; the signal is processed by the low-pass filter circuit, high-frequency noise components are greatly filtered, but the signal amplitude is small, the requirement of an Lora wireless communication module for AD conversion of an input voltage amplitude is difficult to meet, amplification processing is also needed, and the band-pass filter circuit has high-gain amplification and band-pass filter characteristics and is used for effectively inhibiting the original low-frequency interference of the signal and the low-frequency noise mixed with the processing circuit while amplifying the signal; the Lora wireless communication module is used for performing AD conversion on the received vibration signals and sending the vibration signals to the background in a wireless mode. Therefore, the embodiment can suppress common-mode interference caused by the multi-stage operational amplifier structure through the differential amplification circuit, filter high-frequency noise interference through the low-pass filter circuit, suppress low-frequency noise through the band-pass filter circuit, and greatly improve the measurement accuracy of the vibration signal.
Specifically, the vibration sensor of this embodiment is preferably type 941B. The 941B type vibration sensor belongs to an analog sensor, has large size and weight and is not easy to integrate, so that a three-wire terminal is adopted to be connected with a transmitting node, and the 941B type vibration sensor is output by a three-wire system, namely a power line, a signal line and a ground line.
As shown in fig. 2, the differential amplifier circuit of the present embodiment preferably includes operational amplifiers U1 to U3, resistors R1 to R6, and a variable resistor R7. The output end of the vibration sensor is respectively connected with the non-inverting input ends of an operational amplifier U1 and an operational amplifier U2, the inverting input end of the operational amplifier U1 is connected with the inverting input end of the operational amplifier U2 through a variable resistor R7, the output end of the operational amplifier U1 is connected with the inverting input end of the operational amplifier U1 through a resistor R1, the output end of the operational amplifier U2 is connected with the inverting input end of the operational amplifier U2 through a resistor R2, the output end of the operational amplifier U1 sequentially passes through a resistor R3, the resistor R4 is connected with the output end of the operational amplifier U3, the common end of the resistor R3 and the resistor R4 is connected with the non-inverting input end of the operational amplifier U3, the output end of the operational amplifier U2 is further grounded through a resistor R5 and a resistor R6 in sequence, the common end of the resistor R5 and the resistor R6 is connected with the inverting input end of the operational amplifier U3, and the output end of the operational amplifier U3 is further connected with the input end of the low-pass filter circuit.
The differential amplification circuit of the embodiment adopts the in-phase parallel connection structure differential amplification circuit, and is formed by improving a three-stage operational amplifier cascade structure, wherein the operational amplifiers U1 and U2 adopt in-phase input to form a balanced symmetrical differential amplification input stage, so that the input impedance of the circuit is greatly improved; the operational amplifier U3 forms a double-ended input single-ended output stage to further suppress common mode signals of the operational amplifiers U1, U2. In the input stage, the same-phase parallel connection structure is introduced, so that the circuit does not require any form of matching of the external loop resistor to ensure the common-mode rejection capability, and therefore, errors caused by unmatched resistor precision are avoided. In addition, the circuit gain can be conveniently changed by adjusting the resistance value of the variable resistor R7 without influencing the symmetry of the circuit. In order to balance the circuit structure, R1 ═ R2, R3 ═ R5, and R4 ═ R6 are taken.
Further, in this embodiment, it is preferable that the differential amplifier circuit further includes variable resistors R8 to R9, a common terminal between the resistor R3 and the resistor R4 is further grounded via a variable resistor R8, and a common terminal between the resistor R5 and the resistor R6 is further grounded via a variable resistor R9. In this embodiment, a trimming compensation resistor R8R9 is added between the two input terminals of the operational amplifier U3 and ground to compensate for the asymmetry of the resistors, so as to obtain a higher common mode rejection ratio.
As shown in FIG. 3, the low pass filter circuit of the present embodiment preferably includes an operational amplifier U4, resistors R9-R11, and capacitors C1-C3. The output end of the differential amplification circuit is connected with the input end of the band-pass filter circuit through a resistor R9, the common end of the resistor R9 and the input end of the band-pass filter circuit is respectively connected with the inverting input end of an operational amplifier U4 through a capacitor C1 and the output end of an operational amplifier U4 through a capacitor C2, the output end of an amplifier U4 is sequentially grounded through a resistor R11 and a capacitor C3, the common end of a resistor R11 and the capacitor C3 is connected with the inverting input end of the operational amplifier U4 through a resistor R10, and the non-inverting input end of the operational amplifier U4 is grounded.
In an amplifier circuit, any variation in parameters, such as fluctuations in the supply voltage, aging of the components, and variations in semiconductor component parameters with temperature variations, will result in a drift in the output voltage. For an active low pass filter, the temperature drift of the operational amplifier is a significant factor that is not negligible. For a traditional active low-pass filter circuit, a relatively serious temperature drift phenomenon exists.
In this embodiment, the operational amplifier U4 in the low-pass filter circuit is isolated from the main signal channel by the capacitor C1 and the capacitor C2, and the temperature drift voltage signal of the operational amplifier U4 is not superimposed on the main signal channel, thereby achieving the purpose of suppressing the temperature drift. For an active low-pass filter circuit with active devices such as operational amplifiers, besides the temperature drift phenomenon, the filter performance may be affected by the dc offset and dc drift of the operational amplifier. In this embodiment, the operational amplifier U4 in the low-pass filter circuit is isolated from the main signal channel by the capacitor C1 and the capacitor C2, and the dc offset and dc drift signals of the operational amplifier are not superimposed on the main signal channel, so that the purpose of suppressing the dc offset and dc drift is achieved, the filtering performance of the low-pass filter circuit is improved, and the measurement accuracy of the vibration signal is further improved.
As shown in fig. 4, the bandpass filter circuit of the present embodiment preferably includes operational amplifiers U5 to U6, resistors R12 to R19, and capacitors C4 to C7. The output end of the low-pass filter circuit is connected with the inverting input end of an operational amplifier U5 through a capacitor C4 and a resistor R12 in sequence, the non-inverting input end of the operational amplifier U5 is connected with a power supply VCC through a resistor R14, the non-inverting input end of the operational amplifier U5 is grounded through a resistor R15 and a capacitor C5 which are connected in parallel, and the output end of the operational amplifier U5 is connected with the inverting input end of the operational amplifier U5 through a resistor R13. The output end of the operational amplifier U5 is further connected with the inverting input end of the operational amplifier U6 through a capacitor C6 and a resistor R16 in sequence, the non-inverting input end of the operational amplifier U6 is connected with a power supply VCC through a resistor R18, the non-inverting input end of the operational amplifier U6 is further grounded through a resistor R19 and a capacitor C7 which are connected in parallel, the output end of the operational amplifier U6 is connected with the inverting input end of the operational amplifier U6 through a resistor R17, and the output end of the operational amplifier U6 is further connected with the analog input end of the Lora wireless communication module.
In the embodiment, a two-stage cascaded high-gain amplitude limiting band-pass filter circuit is designed in an optimized active differential circuit mode, and each stage of amplification circuit is formed by adding a resistor connected with an input capacitor in series on the basis of the structure of a traditional differential circuit. The power supply voltage is connected to the non-inverting terminal of the operational amplifier through two divider resistors and is used as the DC bias voltage of the operational amplifier. The passband of the amplitude-frequency characteristic of the improved band-pass filter circuit is widest, the frequency characteristic peak of the traditional differential circuit structure is eliminated, the passband filtering performance is best, and the gain of the circuit outside the passband is sharply reduced.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A wireless vibration measurement sensor comprises a vibration sensor and a Lora wireless communication module, and is characterized by further comprising a differential amplification circuit, a low-pass filter circuit and a band-pass filter circuit;
the output end of the vibration sensor is connected with the analog input end of the Lora wireless communication module through the differential amplification circuit, the low-pass filter circuit and the band-pass filter circuit in sequence.
2. A wireless vibration measuring sensor according to claim 1 wherein the vibration sensor is of type 941B.
3. The wireless vibration measuring sensor according to claim 1, wherein the differential amplifying circuit comprises operational amplifiers U1-U3, resistors R1-R6 and a variable resistor R7;
the output end of the vibration sensor is respectively connected with the non-inverting input ends of an operational amplifier U1 and an operational amplifier U2, the inverting input end of the operational amplifier U1 is connected with the inverting input end of the operational amplifier U2 through a variable resistor R7, the output end of the operational amplifier U1 is connected with the inverting input end of the operational amplifier U1 through a resistor R1, the output end of the operational amplifier U2 is connected with the inverting input end of the operational amplifier U2 through a resistor R2, the output end of the operational amplifier U1 sequentially passes through a resistor R3, the resistor R4 is connected with the output end of the operational amplifier U3, the common end of the resistor R3 and the resistor R4 is connected with the non-inverting input end of the operational amplifier U3, the output end of the operational amplifier U2 is further grounded through a resistor R5 and a resistor R6 in sequence, the common end of the resistor R5 and the resistor R6 is connected with the inverting input end of the operational amplifier U3, and the output end of the operational amplifier U3 is further connected with the input end of the low-pass filter circuit.
4. The wireless vibration sensor as claimed in claim 3, wherein the differential amplifier circuit further comprises variable resistors R8-R9, the common terminal of the resistor R3 and the resistor R4 is further grounded via a variable resistor R8, and the common terminal of the resistor R5 and the resistor R6 is further grounded via a variable resistor R9.
5. The wireless vibration measuring sensor of claim 1, wherein the low pass filter circuit comprises an operational amplifier U4, resistors R9-R11 and capacitors C1-C3;
the output end of the differential amplification circuit is connected with the input end of the band-pass filter circuit through a resistor R9, the common end of the resistor R9 and the input end of the band-pass filter circuit is respectively connected with the inverting input end of an operational amplifier U4 through a capacitor C1 and the output end of an operational amplifier U4 through a capacitor C2, the output end of an amplifier U4 is sequentially grounded through a resistor R11 and a capacitor C3, the common end of a resistor R11 and the capacitor C3 is connected with the inverting input end of the operational amplifier U4 through a resistor R10, and the non-inverting input end of the operational amplifier U4 is grounded.
6. The wireless vibration measuring sensor of claim 1, wherein the band-pass filter circuit comprises operational amplifiers U5-U6, resistors R12-R19 and capacitors C4-C7;
the output end of the low-pass filter circuit is sequentially connected with the inverting input end of an operational amplifier U5 through a capacitor C4 and a resistor R12, the non-inverting input end of the operational amplifier U5 is connected with a power supply VCC through a resistor R14, the non-inverting input end of the operational amplifier U5 is grounded through a resistor R15 and a capacitor C5 which are connected in parallel, and the output end of the operational amplifier U5 is connected with the inverting input end of the operational amplifier U5 through a resistor R13;
the output end of the operational amplifier U5 is further connected with the inverting input end of the operational amplifier U6 through a capacitor C6 and a resistor R16 in sequence, the non-inverting input end of the operational amplifier U6 is connected with a power supply VCC through a resistor R18, the non-inverting input end of the operational amplifier U6 is further grounded through a resistor R19 and a capacitor C7 which are connected in parallel, the output end of the operational amplifier U6 is connected with the inverting input end of the operational amplifier U6 through a resistor R17, and the output end of the operational amplifier U6 is further connected with the analog input end of the Lora wireless communication module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022442702.9U CN213455838U (en) | 2020-10-28 | 2020-10-28 | Wireless vibration measurement sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022442702.9U CN213455838U (en) | 2020-10-28 | 2020-10-28 | Wireless vibration measurement sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213455838U true CN213455838U (en) | 2021-06-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022442702.9U Expired - Fee Related CN213455838U (en) | 2020-10-28 | 2020-10-28 | Wireless vibration measurement sensor |
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| CN (1) | CN213455838U (en) |
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2020
- 2020-10-28 CN CN202022442702.9U patent/CN213455838U/en not_active Expired - Fee Related
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Granted publication date: 20210615 |