Signal acquisition circuit and weighing system

Abstract

The utility model provides a signal acquisition circuit and a weighing system, and the signal acquisition circuit comprises a reference power supply which is used for providing a following voltage signal; the acquisition module is used for acquiring and outputting an original vibration signal, and the original vibration signal comprises a direct-current voltage component and an alternating-current voltage component; the differential module is electrically connected with the acquisition module and a reference power supply, receives the vibration original signal and the following voltage signal, and performs differential operation on the vibration original signal and the following voltage signal to eliminate a direct current voltage component in the vibration original signal to obtain a differential signal; the data processing module is electrically connected with the differential module and used for receiving the differential signal, determining a vibration signal according to the differential signal and outputting the vibration signal, so that the accuracy of the collected vibration signal is improved; the technical problem that accurate measurement cannot be achieved due to the fact that direct-current noise in low-frequency alternating-current signals cannot be effectively filtered out in the prior art is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of weighing, in particular to a signal acquisition circuit and a weighing system. Background Art

[0002] The effective signal for feedback vibration information is the AC signal, while the signal frequency of the vibration signals of some roads or buildings is relatively low (very close to the DC signal); as for the results, the DC signal in the collected signal is a useless signal, so it is often necessary to perform AC / DC separation processing on the collected signal.

[0003] In the related technology, the filtering principle is used to separate the signals by "passing AC and blocking DC", which results in the very low-frequency signals being filtered out and the real vibration signal (AC signal) cannot be collected.

[0004] It can be seen that the signal acquisition circuit in the related art has a technical problem of being unable to make accurate measurements due to the inability to effectively filter out DC noise in the low-frequency AC signal. Utility Model Content

[0005] The embodiment of the utility model provides a signal acquisition circuit to at least solve the technical problem in the related art that the DC noise in the low-frequency AC signal cannot be effectively filtered out, which leads to the inability to accurately measure.

[0006] According to one embodiment of the utility model, a signal acquisition circuit is provided, comprising: a reference power supply, used for providing a follow voltage signal; an acquisition module, used for acquiring and outputting a vibration original signal, wherein the vibration original signal comprises a DC voltage component and an AC voltage component; a differential module, electrically connected to the acquisition module and the reference power supply, receiving the vibration original signal and the follow voltage signal, performing a differential operation on the vibration original signal and the follow voltage signal to eliminate the DC voltage component in the vibration original signal and obtain a differential signal; and a data processing module, electrically connected to the differential module, used for receiving the differential signal, determining a vibration signal according to the differential signal, and outputting the vibration signal.

[0007] As an optional scheme, the data processing module is electrically connected to the differential module and the reference power supply, respectively, and is also used to generate a voltage adjustment instruction according to the DC component in the vibration signal, and send the voltage adjustment instruction to the reference power supply; the reference power supply is also used to adjust the size of the follow-up voltage signal according to the voltage adjustment instruction, so that the adjusted follow-up voltage signal has the same size as the DC voltage component in the original vibration signal.

[0008] As an optional solution, the data processing module includes: an analog-to-digital converter, used to perform analog-to-digital conversion on the differential signal output by the differential module and output the converted digital signal; and a processor, used to control the follower voltage signal output by the reference power supply based on the converted digital signal.

[0009] As an optional solution, the output end of the differential module is connected to the differential input end of the analog-to-digital converter, and the analog-to-digital converter is also used to collect the AC voltage value and DC voltage value of the differential signal output by the differential module through a differential input mode to convert the differential signal output by the differential module into a digital signal.

[0010] As an optional solution, the signal acquisition circuit also includes: a voltage converter, the input end of the voltage converter is connected to the output end of the acquisition module, and the output end of the voltage converter is connected to the input end of the differential module, for performing voltage modulation on the original vibration signal output by the acquisition module so that the amplitude of the original vibration signal after amplitude reduction is within the working voltage range of the differential module.

[0011] As an optional solution, the voltage converter proportionally reduces the amplitude of the original vibration signal to 1 / 5 of the amplitude of the original vibration signal.

[0012] As an optional solution, the signal acquisition circuit also includes: a multiple feedback MFB filter circuit, wherein the two input ends of the MFB filter circuit are respectively connected to the output end of the voltage converter and the output end of the reference power supply, and the output end of the MFB filter circuit is connected to the input end of the differential module, for filtering out common mode interference of the voltage signal output by the voltage converter and the follower voltage signal output by the reference power supply.

[0013] As an optional solution, the acquisition module includes: a piezoelectric integrated circuit IEPE sensor, and the voltage signal output by the IEPE sensor includes a 12V DC voltage signal and an AC voltage signal with an amplitude of ±5V.

[0014] As an optional solution, the signal acquisition circuit further includes: a constant current source, the output end of which is connected to the acquisition module, for providing constant current excitation for the acquisition module.

[0015] According to another embodiment of the utility model, a weighing system is provided, comprising any one of the above-mentioned signal acquisition circuits.

[0016] According to the embodiment provided by the utility model, the signal acquisition circuit includes a reference power supply, an acquisition module, a differential module and a data processing module, wherein the follow-up voltage signal provided by the reference power supply and the vibration original signal (including a DC voltage component and an AC voltage component) provided by the acquisition module are received through the differential module, and the vibration original signal and the follow-up voltage signal are differentially operated to eliminate the DC voltage component in the vibration original signal to obtain a differential signal; then, the data processing module electrically connected to the differential module receives the differential signal and determines the vibration signal (AC signal) according to the differential signal, thereby improving the accuracy of the collected vibration signal, thereby solving the technical problem in the related art that the DC noise in the low-frequency AC signal cannot be effectively filtered out, which leads to the inability to accurately measure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an optional signal acquisition circuit provided by an embodiment of the utility model;

[0018] Figure 2 It is a structural schematic diagram of another optional signal acquisition circuit provided by an embodiment of the utility model;

[0019] Figure 3 This is a structural schematic diagram of another optional signal acquisition circuit provided by an embodiment of the utility model;

[0020] Figure 4 This is a structural schematic diagram of another optional signal acquisition circuit provided by an embodiment of the utility model;

[0021] Figure 5 This is a structural schematic diagram of another optional signal acquisition circuit provided by an embodiment of the utility model;

[0022] Figure 6 This is a structural schematic diagram of another optional signal acquisition circuit provided by an embodiment of the utility model;

[0023] Figure 7 It is a schematic diagram of the logic circuit structure of a signal acquisition circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] According to one aspect of an embodiment of the utility model, a signal acquisition circuit is provided, which can be used as a front-end signal conditioning circuit (for example, used in a weighing system) for converting analog signals into digital signals for data acquisition, control processes, execution of calculations, display readouts or other purposes.

[0027] The output signal of the IEPE sensor (acquisition module) carries both AC voltage and DC voltage, where the AC voltage associated with vibration is converted to a voltage level between 7V and 13V. For any given sensor, it has a drift component relative to time, temperature, and excitation current. The vibration signal frequency of some roads or buildings is relatively low, very close to the DC signal, and the useful signal of the feedback vibration is the AC signal. The DC signal is a useless signal in terms of the result, so it is often necessary to separate the voltage signal from AC and DC.

[0028] In the related technologies, most of the technical solutions for interfacing with piezoelectric sensors are AC coupled sensors. While filtering out DC signals, some low-frequency AC signals (useful signals) will also be filtered out, and there is a lack of measurement capability for DC (signals) and extremely low Hz (signals). DC signals will drift during actual use due to the influence of time, temperature and excitation current, thereby affecting the collection and subsequent processing of vibration signals.

[0029] The embodiment of the utility model provides a signal acquisition circuit. For IEPE sensors applied in the field of low-frequency vibration, a driving circuit method can be used to acquire extremely low-frequency AC signals (vibration signals) while filtering out DC signals.

[0030] In an exemplary embodiment, the present utility model provides a signal acquisition circuit, such as Figure 1 As shown, the signal acquisition circuit includes a reference power supply 101 , an acquisition module 102 , a differential module 103 and a data processing module 104 .

[0031] A reference power supply 101, used for providing a following voltage signal;

[0032] The acquisition module 102 is used to acquire and output the original vibration signal, wherein the original vibration signal includes a DC voltage component and an AC voltage component;

[0033] The differential module 103 is electrically connected to the acquisition module 102 and the reference power supply 101, receives the original vibration signal and the following voltage signal, performs a differential operation on the original vibration signal and the following voltage signal to eliminate the DC voltage component in the original vibration signal, and obtains a differential signal;

[0034] The data processing module 104 is electrically connected to the differential module 103, and is used to receive the differential signal, determine the vibration signal according to the differential signal, and output the vibration signal.

[0035] Here, the reference power supply 101 can be implemented as a digital-to-analog converter, which is used to provide a follow-up voltage signal (DC voltage signal) of a corresponding value based on the received digital signal; the acquisition module 102 can be implemented as a piezoelectric integrated circuit sensor (Integral Electronic Piezoelectric, abbreviated as IEPE); the differential module 103 can be implemented as a differential amplifier.

[0036] An integrated electronic piezoelectric (IEPE) sensor is an accelerometer with a built-in charge amplifier or voltage amplifier. Because the amount of electricity generated by the accelerometer is very small, the electrical signal generated by the sensor is easily affected by noise and requires sensitive electronic devices to amplify and condition the signal.

[0037] In the related technology, the filtering principle is used to separate signals by "passing AC and isolating DC", that is, in a DC circuit, the capacitive reactance presented by the capacitor to DC is infinite, which hinders the passage of DC, which is called the DC isolation effect; in an AC circuit, the capacitive reactance presented by the capacitor to AC is very small, which is conducive to the passage of AC current, which is called the AC passing effect; however, such a scheme will cause extremely low-frequency signals to be filtered out, and the real vibration signal cannot be collected. In addition, when the sensor collects vibration signals, it is often accompanied by the problem of zero drift (that is, when the input signal of the amplifier circuit is zero, due to the influence of factors such as temperature changes and unstable power supply voltage, the static operating point changes, and is amplified and transmitted step by step, causing the circuit output voltage to deviate from the original fixed value and drift up and down), which seriously affects the collection and processing of vibration signals.

[0038] Since the voltage signal (original vibration signal) input from the acquisition module 102 to the differential module 103 is a bias voltage with a DC signal and is accompanied by a low-frequency AC signal output (DC voltage component and AC voltage component), in order to acquire an AC signal carrying valid information, the embodiment of the utility model outputs a follower voltage signal of a preset value through the reference power supply 101, and performs differential processing on the original vibration signal output by the acquisition module 102 and the follower voltage signal output by the reference power supply 101 through the differential module 103, filters out the DC voltage component in the original vibration signal output by the acquisition module 102, and obtains the differential signal output by the differential module 103.

[0039] Here, since the DC signal in the original vibration signal output by the acquisition module 102 cancels out the follow-up voltage signal of the preset value output by the reference power supply 101 , the differential signal output by the differential module 103 is the AC voltage component in the original vibration signal output by the acquisition module 102 .

[0040] It should be noted that the output signal of the acquisition module 102 (for example, an IEPE sensor) is a preset value or a measurable value. For example, the output signal of the IEPE sensor is usually a DC signal of about 12V accompanied by a low-frequency AC signal with an amplitude of ±5V. Therefore, the reference power supply 101 can set a reference signal (DC signal) of a preset value to offset (partially or fully offset) the DC signal output by the IEPE sensor.

[0041] After receiving the differential signal output by the differential module 103 , the data processing module 104 determines the vibration signal according to the differential signal and outputs the vibration signal.

[0042] The signal acquisition circuit provided by the utility model includes a reference power supply for providing a follow-up voltage signal; an acquisition module for acquiring and outputting an original vibration signal, wherein the original vibration signal includes a DC voltage component and an AC voltage component; a differential module electrically connected to the acquisition module and the reference power supply, receiving the original vibration signal and the follow-up voltage signal, performing a differential operation on the original vibration signal and the follow-up voltage signal to eliminate the DC voltage component in the original vibration signal and obtain a differential signal; and a data processing module electrically connected to the differential module for receiving the differential signal, determining the vibration signal according to the differential signal, and outputting the vibration signal, thereby improving the accuracy of the acquired vibration signal and solving the technical problem in the related art that the DC noise in the low-frequency AC signal cannot be effectively filtered out and cannot be accurately measured.

[0043] In an exemplary embodiment, the data processing module 104 is electrically connected to the differential module 103 and the reference power supply 101, respectively, and is further used to generate a voltage adjustment instruction according to the DC component in the vibration signal, and send the voltage adjustment instruction to the reference power supply 101;

[0044] The reference power supply 101 is also used to adjust the magnitude of the following voltage signal according to the voltage adjustment instruction, so that the magnitude of the adjusted following voltage signal is the same as the DC voltage component in the original vibration signal.

[0045] The differential signal output by the differential module 103 is converted into an analog-to-digital signal by the data processing module 104 to determine the vibration signal; and a voltage adjustment instruction is generated according to the DC component in the vibration signal. Here, the voltage adjustment instruction is used to control the signal voltage of the follow-up voltage signal output by the reference power supply 101, so as to continuously calibrate the follow-up voltage signal output by the reference power supply 101, so that the follow-up voltage signal output by the reference power supply 101 and the DC voltage component in the original vibration signal output by the acquisition module 102 are offset.

[0046] Since the DC voltage component (DC voltage component) in the vibration signal is equal to the average value of the vibration signal (the DC voltage component of the signal is equal to the average value of the signal), the voltage adjustment instruction generated by the data processing module 104, where the voltage value of the follow voltage signal indicated by the voltage modulation instruction is equal to the average value of the current vibration signal, is used to correct the value of the follow voltage signal. The reference power supply 101 adjusts the size of the follow voltage signal according to the voltage adjustment instruction so that the adjusted follow voltage signal is the same size as the DC voltage component in the original vibration signal, so as to offset the DC voltage component in the original vibration signal output by the acquisition module 102.

[0047] Through the embodiment provided by the utility model, a voltage adjustment instruction is generated based on the DC component in the vibration signal through the data processing module, and the follow-up voltage signal provided by the reference power supply is continuously calibrated to offset the DC voltage component in the original vibration signal output by the acquisition module, thereby continuously outputting an accurate vibration signal.

[0048] In an exemplary embodiment, reference Figure 2 , the data processing module 104 includes:

[0049] an analog-to-digital converter connected to the output end of the differential module, used for performing analog-to-digital conversion on the differential signal output by the differential module and outputting the converted digital signal; and

[0050] The processor is connected to the analog-to-digital converter and the reference power supply respectively, and is used to determine the vibration signal based on the converted digital signal and output it; and to generate a voltage adjustment instruction based on the DC component in the vibration signal and send the voltage adjustment instruction to the reference power supply.

[0051] An analog to digital converter (ADC) is electrically connected to the differential module 103 and the processor, respectively, and is used to perform analog-to-digital conversion on the differential signal output by the differential module, and output the converted digital signal;

[0052] The processor can be implemented as a microcontroller unit MCU processor, which is electrically connected to the reference power supply 101 and the analog-to-digital converter respectively, and is used to determine the vibration signal based on the converted digital signal and output it; and to generate a voltage adjustment instruction based on the DC component in the vibration signal and send the voltage adjustment instruction to the reference power supply.

[0053] In some embodiments, the analog-to-digital converter can collect the AC voltage and DC voltage values ​​output by the differential module through a differential input mode; the differential input mode means that the analog-to-digital converter simultaneously collects the difference between two input signals instead of collecting the value of each signal separately; this method can improve the signal's anti-interference ability while reducing the impact of common-mode interference.

[0054] For example, to collect the AC voltage and DC voltage output by the differential module, the output of the differential module can be connected to the differential input port of the analog-to-digital converter. The analog-to-digital converter samples and converts the differential input signal and converts it into a digital signal. During the data processing process, the collected differential signal can be processed as needed to extract the information of the AC voltage and DC voltage.

[0055] Here, the differential input mode is used to improve the anti-interference ability and effectively suppress electromagnetic interference compared to the single-ended signal routing method.

[0056] After collecting the digital signal, the processor determines the vibration signal based on the digital signal and outputs it. At the same time, based on the DC component in the vibration signal, it generates a voltage adjustment instruction to control the follow-up voltage signal output by the reference power supply 101, so that the DC voltage of the follow-up voltage signal output by the reference power supply 101 is equal to the DC voltage of the voltage signal output by the acquisition module.

[0057] The analog-to-digital converter collects the differential signal output by the differential module 103 and performs analog-to-digital conversion on the differential signal to output a digital signal, and outputs the average value of the digital signal to the processor. Based on the average value of the digital signal, the processor determines the DC voltage amount of the follower voltage signal output by the reference power supply 101 next time.

[0058] Through the embodiment provided by the utility model, a voltage adjustment instruction can be generated based on the DC component in the vibration signal, so as to facilitate the subsequent adjustment of the DC voltage amount of the output follower voltage signal of the reference power supply to accurately offset the DC voltage amount of the output voltage signal of the acquisition module (or voltage converter).

[0059] In an exemplary embodiment, the reference power source is a digital-to-analog converter, and the digital-to-analog converter is used to generate a following voltage signal according to a voltage adjustment instruction.

[0060] When the reference power source is implemented as a digital-to-analog converter, the digital-to-analog converter is electrically connected to the processor and the differential module respectively. The digital-to-analog converter is used to receive a voltage adjustment instruction sent by the processor and generate a follow voltage signal according to the voltage adjustment instruction to output to the differential module.

[0061] In an exemplary embodiment, reference Figure 3 , the above-mentioned signal acquisition circuit also includes:

[0062] The voltage converter 301, the input end of the voltage converter 301 is connected to the output end of the acquisition module 102, and the output end of the voltage converter 301 is connected to the input end of the differential module 103, and is used to perform voltage modulation on the original vibration signal output by the acquisition module 102, so that the amplitude of the original vibration signal after amplitude reduction is within the working voltage range of the differential module.

[0063] The voltage converter 301 is used to receive the voltage signal output by the acquisition module 102, and to perform voltage modulation on the signal voltage of the voltage signal, so as to proportionally reduce the amplitude of the original vibration signal output by the acquisition module 102, that is, according to the ratio of the DC signal to the AC signal in the original vibration signal output by the acquisition module 102, the original vibration signal is proportionally reduced so that the amplitude of the original vibration signal after the reduction is within the operating voltage range of the differential module 103.

[0064] In an exemplary embodiment, the voltage converter proportionally reduces the amplitude of the vibration original signal to 1 / 5 of the amplitude of the vibration original signal.

[0065] For example, the original vibration signal output by the acquisition module 102 is proportionally reduced to one fifth of the initial value by the voltage converter 301, wherein the ratio of the DC signal to the AC signal in the voltage signal remains unchanged;

[0066] For example, the voltage signal output by the IEPE sensor includes a 12V DC voltage signal and an AC voltage signal with an amplitude of ±5V. The voltage signal is proportionally reduced to within 0 to 5V through the voltage converter 301. At this time, the voltage signal obtained after the reduction includes a 2.4V DC voltage signal and an AC voltage signal with an amplitude of ±1V.

[0067] Through the embodiment provided by the utility model, before the original vibration signal output by the acquisition module is transmitted to the differential module, the signal voltage is modulated by a voltage converter, which can effectively reduce the signal voltage to the tolerance range of the differential module and stabilize the voltage.

[0068] In an exemplary embodiment, reference Figure 4 , the above-mentioned signal acquisition circuit also includes:

[0069] A multiple feedback MFB filter circuit 401, wherein two input terminals of the MFB filter circuit 401 are respectively connected to the output terminal of the voltage converter 301 and the output terminal of the reference power supply 101, and the output terminal of the MFB filter circuit 401 is connected to the input terminal of the differential module 103, and is used to filter out common mode interference of the voltage signal output by the voltage converter 301 and the following voltage signal output by the reference power supply 101.

[0070] Multiple Feedback (MFB) filter circuit is a commonly used electronic filter, which has frequency selectivity and can filter out signals in a specific frequency range.

[0071] The working principle of the MFB filter circuit is to use the feedback mechanism of the operational amplifier to achieve the filtering function. Specifically, it controls the feedback path and amplification factor of the operational amplifier through the combination of capacitors and resistors, thereby determining the frequency response of the filter. In the MFB filter circuit, the values ​​of capacitors and resistors can be adjusted as needed to achieve different filtering effects.

[0072] MFB filter circuit can realize various filtering functions such as low-pass, high-pass, band-pass and band-stop. In low-pass filter, only low-frequency signals can pass through and high-frequency signals are filtered out; in high-pass filter, only high-frequency signals can pass through and low-frequency signals are filtered out. Band-pass filter can select signals within a certain frequency range to pass through, while band-stop filter can select signals within a certain frequency range to be filtered out.

[0073] Through the embodiment of the utility model, the MFB filter circuit is used to adjust the input of the differential module, and the frequency response of the filter can be adjusted as needed. In addition, the MFB filter circuit also has good anti-interference ability and low noise level.

[0074] In an exemplary embodiment, reference Figure 5 , the above acquisition module includes:

[0075] Piezoelectric integrated circuit IEPE sensor, the voltage signal output by the IEPE sensor includes a 12V DC voltage signal and an AC voltage signal with an amplitude of ±5V.

[0076] In some embodiments, the IEPE sensor outputs an output voltage signal including a 12V DC voltage signal and an AC voltage signal with an amplitude of ±5V to a voltage converter or a differential module.

[0077] Because the amount of electricity generated by the accelerometer is very small, the electrical signal generated by the sensor is easily interfered by noise, and sensitive electronic devices are needed to amplify and condition the signal. IEPE sensors integrate sensitive electronic devices as close to the sensor as possible to ensure better noise resistance and easier packaging.

[0078] IEPE accelerometers have an internal charge amplifier. An external current source introduces current into the accelerometer. The circuitry inside the accelerometer makes it behave like a resistor. The acceleration of the sensor is proportional to the resistance it presents. Therefore, the signal voltage returned by the sensor is also proportional to the acceleration. The amplifier allows the input range to be set to make the best use of the input signal.

[0079] In an exemplary embodiment, reference Figure 6 , the above-mentioned signal acquisition circuit also includes:

[0080] The constant current source 601 has an output end connected to the acquisition module, and is used to provide constant current excitation for the acquisition module.

[0081] A constant current source 601 , wherein an output end of the constant current source 601 is connected to the acquisition module 102 , and is used to provide constant current excitation for the acquisition module 102 .

[0082] Within the power range, the current output by the constant current source 601 to the acquisition module 102 is basically constant and does not change due to changes in load (output voltage); it does not change due to changes in ambient temperature; and the internal resistance is infinite (so that all the current can flow out).

[0083] Here, when the constant current provided by the constant current source 601 to the acquisition module 102 is within 10 mA, for example, it may be 4 mA.

[0084] Through the embodiment provided by the utility model, a constant current source is used to provide a constant current for IEPE, so that the current can be accurately output and errors caused by current fluctuations can be avoided.

[0085] In an exemplary embodiment, reference Figure 7 , Figure 7 It is a schematic diagram of the logic circuit structure of a signal acquisition circuit provided by an embodiment of the utility model; it includes a constant current source, an IEPE sensor, a voltage converter, a digital-to-analog converter, an MFB filter circuit, a differential amplifier circuit, an analog-to-digital converter, and an MCU processing unit.

[0086] The constant current source is used to provide a constant current to the IEPE sensor;

[0087] IEPE sensor, used to output voltage signals including 12V DC voltage signal and ±5V AC voltage signal;

[0088] A voltage converter, used to reduce the amplitude of the voltage signal output by the IEPE sensor to one fifth;

[0089] A digital-to-analog converter, used for outputting a zero-point reference voltage according to an average value of a signal output by the analog-to-digital converter;

[0090] MFB filter circuit is used to filter out common mode interference.

[0091] The differential amplifier circuit (differential amplifier) ​​is used to realize single-ended to differential conversion, and to differentiate DC signals and adjust AC signals;

[0092] An analog-to-digital converter, used to collect the single-ended to differential signal of the differential amplifier circuit;

[0093] The MCU processing unit is used to collect the analog-to-digital converter data and adjust the digital-to-analog converter output.

[0094] The specific circuit structure of each module can be found in the above or Figure 7 , I will not go into details here.

[0095] The signal acquisition circuit provided by the utility model can be used for collecting useful signals of IEPE sensors for pre-processing.

[0096] According to another aspect of the embodiments of the utility model, a weighing system is provided. The weighing system can use the signal acquisition circuit shown in any of the aforementioned embodiments.

[0097] In an exemplary embodiment, the utility model provides a weighing system, comprising:

[0098] A signal acquisition circuit, wherein the signal acquisition circuit includes a reference power supply, an acquisition module, a differential module and a data processing module;

[0099] A reference power supply, used to provide a following voltage signal;

[0100] An acquisition module, used for acquiring and outputting an original vibration signal, wherein the original vibration signal includes a DC voltage component and an AC voltage component;

[0101] The differential module is electrically connected to the acquisition module and the reference power supply, receives the original vibration signal and the following voltage signal, performs differential operation on the original vibration signal and the following voltage signal to eliminate the DC voltage component in the original vibration signal, and obtains a differential signal;

[0102] The data processing module is electrically connected to the differential module, and is used for receiving the differential signal, determining the vibration signal according to the differential signal, and outputting the vibration signal.

[0103] As an optional implementation scheme, the data processing module is electrically connected to the differential module and the reference power supply, respectively, and is also used to generate a voltage adjustment instruction based on the DC component in the vibration signal, and send the voltage adjustment instruction to the reference power supply; the reference power supply is also used to adjust the size of the follow-up voltage signal according to the voltage adjustment instruction, so that the adjusted follow-up voltage signal has the same size as the DC voltage component in the original vibration signal.

[0104] As an optional implementation scheme, the data processing module includes: an analog-to-digital converter, connected to the output end of the differential module, for performing analog-to-digital conversion on the differential signal output by the differential module, and outputting the converted digital signal; a processor, connected to the analog-to-digital converter and a reference power supply respectively, for determining a vibration signal based on the converted digital signal, and outputting it; and, generating a voltage adjustment instruction based on the DC component in the vibration signal, and sending the voltage adjustment instruction to the reference power supply.

[0105] As an optional implementation, the reference power supply is a digital-to-analog converter, and the digital-to-analog converter is used to generate a follow-up voltage signal according to the voltage adjustment instruction.

[0106] As an optional implementation, the above-mentioned signal acquisition circuit also includes: a voltage converter, the input end of the voltage converter is connected to the output end of the acquisition module, and the output end of the voltage converter is connected to the input end of the differential module, which is used to perform voltage modulation on the original vibration signal output by the acquisition module so that the amplitude of the original vibration signal after amplitude reduction is within the working voltage range of the differential module.

[0107] As an optional implementation, the voltage converter mentioned above proportionally reduces the amplitude of the original vibration signal to 1 / 5 of the amplitude of the original vibration signal.

[0108] As an optional implementation scheme, the above-mentioned signal acquisition circuit also includes: a multiple feedback MFB filter circuit, the two input ends of the MFB filter circuit are respectively connected to the output end of the voltage converter and the output end of the reference power supply, and the output end of the MFB filter circuit is connected to the input end of the differential module, which is used to filter out the common mode interference of the voltage signal output by the voltage converter and the follower voltage signal output by the reference power supply.

[0109] As an optional implementation, the acquisition module includes: a piezoelectric integrated circuit IEPE sensor, and the voltage signal output by the IEPE sensor includes a 12V DC voltage signal and an AC voltage signal with an amplitude of ±5V.

[0110] As an optional implementation scheme, the above-mentioned signal acquisition circuit further includes:

[0111] A constant current source, the output end of which is connected to the acquisition module, is used to provide constant current excitation for the acquisition module.

[0112] According to the embodiment provided by the utility model, the signal acquisition circuit includes a reference power supply, an acquisition module, a differential module and a data processing module, wherein the follow-up voltage signal provided by the reference power supply and the vibration original signal (including a DC voltage component and an AC voltage component) provided by the acquisition module are received by the differential module, and the vibration original signal and the follow-up voltage signal are differentially operated to eliminate the DC voltage component in the vibration original signal to obtain a differential signal; then, the data processing module electrically connected to the differential module receives the differential signal and determines the vibration signal (AC signal) according to the differential signal, thereby improving the accuracy of the collected vibration signal and solving the technical problem in the related art that the DC noise in the low-frequency AC signal cannot be effectively filtered out, which leads to the inability to accurately measure.

[0113] In the description of the present invention, it should be understood that the terms used, such as “center”, “length”, “width”, “thickness”, “top”, “bottom”, “up”, “down”, “left”, “right”, “front”, “back”, “vertical”, “horizontal”, “inside”, “outside”, “axial”, “circumferential”, etc., to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the position or component referred to must have a specific direction, a specific structure and operation, and therefore cannot be understood as a limitation on the present invention.

[0114] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, they can be fixedly connected, detachably connected, or integrated; they can be mechanically connected, electrically connected, or can communicate with each other; they can be directly connected, or indirectly connected through an intermediate medium, so that the internal communication of two elements or the interaction relationship between two elements can be achieved. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0115] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the embodiments of the present invention. For those skilled in the art, the embodiments of the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the principles of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention. The specific examples in this embodiment can refer to the examples described in the above embodiments and exemplary implementations, and this embodiment will not be repeated here.

[0117] Obviously, those skilled in the art should understand that the modules or steps of the above-mentioned embodiments of the utility model can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order from that here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. In this way, the embodiments of the utility model are not limited to any specific combination of hardware and software.

[0118] The above description is only the preferred embodiment of the utility model, and is not intended to limit the embodiment of the utility model. For those skilled in the art, the embodiment of the utility model can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the embodiment of the utility model shall be included in the protection scope of the embodiment of the utility model.

Claims

1. A signal acquisition circuit, characterized in that: include: A reference power supply, used to provide a following voltage signal; An acquisition module, used for acquiring and outputting an original vibration signal, wherein the original vibration signal includes a DC voltage component and an AC voltage component; A differential module is electrically connected to the acquisition module and the reference power supply, receives the original vibration signal and the follow-up voltage signal, performs a differential operation on the original vibration signal and the follow-up voltage signal to eliminate a DC voltage component in the original vibration signal, and obtains a differential signal; The data processing module is electrically connected to the differential module, and is used to receive the differential signal, determine the vibration signal according to the differential signal, and output the vibration signal.

2. The signal acquisition circuit according to claim 1, characterized in that: The data processing module is electrically connected to the differential module and the reference power supply, respectively, and is further used to generate a voltage adjustment instruction according to a DC component in the vibration signal, and send the voltage adjustment instruction to the reference power supply; The reference power supply is further used to adjust the magnitude of the follow voltage signal according to the voltage adjustment instruction so that the adjusted follow voltage signal has the same magnitude as the DC voltage component in the original vibration signal.

3. The signal acquisition circuit according to claim 2, characterized in that: The data processing module comprises: an analog-to-digital converter, connected to the output end of the differential module, for performing analog-to-digital conversion on the differential signal output by the differential module, and outputting the converted digital signal; and A processor is connected to the analog-to-digital converter and the reference power supply respectively, and is used to determine the vibration signal based on the converted digital signal and output it; and to generate the voltage adjustment instruction based on the DC component in the vibration signal and send the voltage adjustment instruction to the reference power supply.

4. The signal acquisition circuit according to claim 2, characterized in that: The reference power supply is a digital-to-analog converter, and the digital-to-analog converter is used to generate the following voltage signal according to the voltage adjustment instruction.

5. The signal acquisition circuit according to claim 1, characterized in that: The signal acquisition circuit also includes: A voltage converter, wherein the input end of the voltage converter is connected to the output end of the acquisition module, and the output end of the voltage converter is connected to the input end of the differential module, and is used to perform voltage modulation on the original vibration signal output by the acquisition module so that the amplitude of the original vibration signal after amplitude reduction is within the working voltage range of the differential module.

6. The signal acquisition circuit according to claim 5, characterized in that: The voltage converter proportionally reduces the amplitude of the vibration original signal to 1 / 5 of the amplitude of the vibration original signal.

7. The signal acquisition circuit according to claim 5, characterized in that: The signal acquisition circuit also includes: A multiple feedback MFB filter circuit, wherein the two input ends of the MFB filter circuit are respectively connected to the output end of the voltage converter and the output end of the reference power supply, and the output end of the MFB filter circuit is connected to the input end of the differential module, for filtering out common mode interference of the voltage signal output by the voltage converter and the follower voltage signal output by the reference power supply.

8. The signal acquisition circuit according to claim 1, characterized in that: The acquisition module comprises: A piezoelectric integrated circuit IEPE sensor, wherein the voltage signal output by the IEPE sensor includes a 12V DC voltage signal and an AC voltage signal with an amplitude of ±5V.

9. The signal acquisition circuit according to any one of claims 1 to 8, characterized in that: The signal acquisition circuit also includes: A constant current source, the output end of which is connected to the acquisition module, is used to provide constant current excitation for the acquisition module.

10. A weighing system, characterized in that: The invention comprises the signal acquisition circuit according to any one of claims 1 to 9.

Images