Multi-sensor synchronous acquisition circuit

Abstract

The utility model relates to a kind of multi-sensor synchronous acquisition circuit, including temperature compensation diode, vibration sampling circuit, self-checking circuit, temperature sampling circuit, multiplexer, sampling chip and main control module;The input end of vibration sensor is electrically connected with the cathode of temperature compensation diode;The input end of self-checking circuit is electrically connected with the cathode of temperature compensation diode;The input end of temperature sensor is electrically connected with the cathode of temperature compensation diode;The first input end of multiplexer is electrically connected with the output end of self-checking circuit.The utility model introduces temperature compensation diode, improves the working stability and measurement accuracy of vibration sensor and temperature sensor.Self-checking circuit and temperature sensor make that main control module can be switched multiplexer, actively collect the verification signal generated by self-checking circuit, to verify the integrity of front-end power supply and signal path in real time without interrupting normal monitoring, realize online self-checking function.

Description

Technical Field

[0001] This utility model relates to the field of sensor signal acquisition technology, specifically to a multi-sensor synchronous acquisition circuit. Background Technology

[0002] In fields such as industrial equipment condition monitoring, fault prediction, and health management, it is often necessary to synchronously or asynchronously acquire various physical signals such as vibration and temperature to comprehensively assess the equipment's operating status. Among these, IEPE type vibration sensors are widely used for vibration measurement due to their advantages such as built-in signal conditioning circuitry, low output impedance, and long signal transmission distance. Vibration sensors require a constant current source to drive their internal circuitry, and their output signal is an AC vibration signal superimposed on a DC bias voltage.

[0003] However, the following technical problems exist in practical applications: 1. Constant current source temperature drift problem: The output current of traditional constant current sources is easily affected by changes in ambient temperature, leading to unstable current supplied to the vibration sensor. Current drift directly affects the operating point of the sensor's internal amplifier circuit, thereby causing fluctuations in the DC bias of the sensor's output signal. In severe cases, this can affect the measurement accuracy and long-term reliability of AC vibration signals.

[0004] 2. Lack of online self-test mechanism: Existing IEPE signal acquisition circuits typically lack effective online self-test functionality. They cannot proactively verify the functionality of the front-end power supply circuit and signal path in real time during data acquisition. If an anomaly occurs in the front-end circuit (such as constant current source failure or loose connectors), the acquisition system may still be operating, but the acquired data will be invalid, posing a risk of data loss and misjudgment of device status.

[0005] 3. Insufficient vibration signal conditioning: The effective vibration signal is usually located in a specific frequency band (e.g., 1Hz~20kHz), while the field environment contains DC offset introduced by the sensor itself or its installation, 50 / 60Hz power frequency interference, and higher frequency electromagnetic noise. Existing acquisition circuit filtering schemes often have low order, resulting in a gentle attenuation slope near the cutoff frequency, leading to insufficient stopband rejection and a need to improve the signal-to-noise ratio (SNR). Simultaneously, the vibration signal has a large dynamic range; without proper attenuation conditioning, strong signals can easily saturate the downstream analog-to-digital converter (ADC), while weak signals may be distorted due to excessive quantization errors. Utility Model Content

[0006] Based on the above description, this utility model provides a multi-sensor synchronous acquisition circuit, which aims to solve the problem of insufficient measurement accuracy of vibration sensors caused by the unstable output current of existing constant current sources.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A multi-sensor synchronous acquisition circuit includes: A temperature compensation diode, wherein the anode of the temperature compensation diode is electrically connected to the output terminal of a constant current source; A vibration sampling circuit includes a vibration sensor, the input terminal of which is electrically connected to the cathode of the temperature compensation diode; The self-test circuit has its input terminal electrically connected to the cathode of the temperature compensation diode. A temperature sampling circuit includes a temperature sensor, the input terminal of which is electrically connected to the cathode of the temperature compensation diode; A multiplexer, wherein the first input terminal of the multiplexer is electrically connected to the output terminal of the self-test circuit, and the second input terminal of the multiplexer is electrically connected to the output terminal of the temperature sensor; A sampling chip, wherein the input terminal of the sampling chip is electrically connected to the output terminal of the vibration sensor and the output terminal of the multiplexer; The main control module is electrically connected to the output of the sampling chip.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the vibration sampling circuit includes a high-pass filter, the input terminal of which is electrically connected to the output terminal of the vibration sensor, and the output terminal of which is electrically connected to the input terminal of the sampling chip.

[0010] Furthermore, the vibration sampling circuit includes a Butterworth fourth-order low-pass filter, the input terminal of which is electrically connected to the output terminal of the high-pass filter, and the output terminal of which is electrically connected to the input terminal of the sampling chip.

[0011] Furthermore, the vibration sampling circuit includes a first common-mode inductor, the input terminal of which is electrically connected to the output terminal of the vibration sensor, and the output terminal of which is electrically connected to the input terminal of the high-pass filter.

[0012] Furthermore, the vibration sampling circuit includes an attenuator, the input terminal of which is electrically connected to the output terminal of the Butterworth fourth-order low-pass filter, and the output terminal of which is electrically connected to the input terminal of the sampling chip.

[0013] Furthermore, the self-test circuit includes a proportional voltage divider circuit, a first voltage follower, and an impedance matching circuit. The input terminal of the proportional voltage divider circuit is electrically connected to the cathode of the temperature compensation diode. The input terminal of the first voltage follower is electrically connected to the output terminal of the proportional voltage divider circuit. The input terminal of the impedance matching circuit is electrically connected to the output terminal of the first voltage follower. The output terminal of the impedance matching circuit is electrically connected to the first input terminal of the multiplexer.

[0014] Furthermore, the temperature sampling circuit includes a second voltage follower, the input terminal of which is electrically connected to the output terminal of the temperature sensor, and the output terminal of which is electrically connected to the second input terminal of the multiplexer.

[0015] Furthermore, the temperature sampling circuit includes a TVS protection diode, one end of which is electrically connected to the output terminal of the temperature sensor, and the other end of which is electrically connected to the input terminal of the second voltage follower.

[0016] Furthermore, the temperature sampling circuit includes a second common-mode inductor, the input terminal of which is electrically connected to the other end of the TVS protection diode, and the output terminal of which is electrically connected to the input terminal of the second voltage follower.

[0017] Furthermore, the temperature sampling circuit includes a low-pass filter circuit, the input terminal of which is electrically connected to the output terminal of the second common-mode inductor, and the output terminal of which is electrically connected to the input terminal of the second voltage follower.

[0018] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: (1) This utility model improves the working stability and measurement accuracy of the vibration sensor and temperature sensor by introducing a temperature compensation diode. The self-test circuit and temperature sensor enable the main control module to actively collect the verification signal generated by the self-test circuit by switching the multiplexer, thereby verifying the integrity of the front-end power supply and signal path in real time without interrupting normal monitoring, and realizing the online self-test function.

[0019] (2) This utility model uses a high-pass filter to filter out the DC component and extremely low frequency noise in the vibration signal, thereby eliminating the DC bias introduced by non-vibration factors and ensuring that the back-end circuit works in the linear region.

[0020] (3) The present invention uses the second voltage follower to perform impedance transformation and isolation. Its high input impedance reduces the influence on the temperature sensor, and its low output impedance drives the subsequent multiplexer and sampling chip, thus ensuring the accuracy of temperature signal acquisition. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a circuit connection diagram of a multi-sensor synchronous acquisition circuit provided in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures: 1. Constant current source; 2. Temperature compensation diode; 3. Vibration sampling circuit; 31. Vibration sensor; 32. High-pass filter; 33. Butterworth fourth-order low-pass filter; 34. First common-mode inductor; 35. Attenuator; 4. Self-test circuit; 41. Proportional voltage divider circuit; 42. First voltage follower; 43. Impedance matching circuit; 5. Temperature sampling circuit; 51. Temperature sensor; 52. Second voltage follower; 53. TVS protection diode; 54. Second common-mode inductor; 55. Low-pass filter circuit; 6. Multiplexer; 7. Sampling chip; 8. Main control module. Detailed Implementation

[0024] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be more thorough and complete.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0026] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "above," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "below" of the other element or feature will be oriented "above" the other element or feature. Therefore, the exemplary terms "below" and "below" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0027] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0028] Reference Figure 1 As shown, this utility model provides a technical solution: a multi-sensor synchronous acquisition circuit, including a temperature compensation diode 2, a vibration sampling circuit 3, a self-test circuit 4, a temperature sampling circuit 5, a multiplexer 6, a sampling chip 7, and a main control module 8; the anode of the temperature compensation diode 2 is electrically connected to the output terminal of the constant current source 1; the vibration sampling circuit 3 includes a vibration sensor 31, the input terminal of which is electrically connected to the cathode of the temperature compensation diode 2; the input terminal of the self-test circuit 4 is electrically connected to the cathode of the temperature compensation diode 2; the temperature sampling circuit 5 includes a temperature sensor 51, the input terminal of which is electrically connected to the cathode of the temperature compensation diode 2; the first input terminal of the multiplexer 6 is electrically connected to the output terminal of the self-test circuit 4, and the second input terminal of the multiplexer 6 is electrically connected to the output terminal of the temperature sensor 51; the input terminal of the sampling chip 7 is electrically connected to the output terminal of the vibration sensor 31 and the output terminal of the multiplexer 6; the input terminal of the main control module 8 is electrically connected to the output terminal of the sampling chip 7.

[0029] In this embodiment, the temperature characteristics of the temperature compensation diode 2 are used to compensate the output of the constant current source 1, thereby suppressing current drift caused by changes in ambient temperature and providing a stable operating current for the subsequent vibration sensor 31 and temperature sensor 51. The vibration sensor 31, self-test circuit 4, and temperature sensor 51 all obtain stable power from the cathode of the temperature compensation diode 2, ensuring that each signal source operates under the same power supply conditions, which is beneficial for achieving synchronous signal acquisition. The sampling chip 7 is used to acquire vibration signals in real time; the output of the self-test circuit 4 and the output of the temperature sensor 51 are selected by the multiplexer 6, allowing the self-test signal or temperature signal to be selectively sent to the sampling chip 7 for sampling. The sampling chip 7 converts the acquired analog signals such as vibration signals, self-test signals, and temperature signals into digital signals and transmits them to the main control module 8 for processing and analysis. By introducing the temperature compensation diode 2, the working stability and measurement accuracy of the vibration sensor 31 and temperature sensor 51 are improved. The self-test circuit 4 and temperature sensor 51 enable the main control module 8 to actively acquire the verification signal generated by the self-test circuit 4 by switching the multiplexer 6, thereby verifying the integrity of the front-end power supply and signal path in real time without interrupting normal monitoring, and realizing the online self-test function.

[0030] Reference Figure 1 As shown, in some embodiments, the vibration sampling circuit 3 includes a high-pass filter 32, the input terminal of which is electrically connected to the output terminal of the vibration sensor 31, and the output terminal of which is electrically connected to the input terminal of the sampling chip 7.

[0031] In this embodiment, the high-pass filter 32 is used to filter out the DC component and extremely low frequency noise in the vibration signal, thereby eliminating the DC bias introduced by non-vibration factors and ensuring that the back-end circuit operates in the linear region.

[0032] Reference Figure 1 As shown, in some embodiments, the vibration sampling circuit 3 includes a Butterworth fourth-order low-pass filter 33, the input terminal of which is electrically connected to the output terminal of the high-pass filter 32, and the output terminal of which is electrically connected to the input terminal of the sampling chip 7.

[0033] In this embodiment, the vibration signal after high-pass filtering is sent to a Butterworth fourth-order low-pass filter 33. It can effectively suppress high-frequency noise and interference above the cutoff frequency. The Butterworth type ensures the flattest amplitude response of the vibration signal within the passband, reducing the distortion of the vibration signal within the passband, thereby achieving a higher signal-to-noise ratio and fidelity within the effective frequency band.

[0034] Reference Figure 1As shown, in some embodiments, the vibration sampling circuit 3 includes a first common-mode inductor 34, the input terminal of the first common-mode inductor 34 is electrically connected to the output terminal of the vibration sensor 31, and the output terminal of the first common-mode inductor 34 is electrically connected to the input terminal of the high-pass filter 32.

[0035] In this embodiment, the first common-mode inductor 34 presents low impedance to the vibration signal on the signal line, allowing the vibration signal to pass through. The first common-mode inductor 34 can suppress common-mode interference coupled to the signal line during transmission, further purifying the vibration signal that is about to enter the high-pass filter 32, thereby improving the electromagnetic interference immunity of the vibration sampling circuit 3.

[0036] Reference Figure 1 As shown, in some embodiments, the vibration sampling circuit 3 includes an attenuator 35, the input of which is electrically connected to the output of a Butterworth fourth-order low-pass filter 33, and the output of which is electrically connected to the input of the sampling chip 7.

[0037] In this embodiment, attenuator 35 is connected between the Butterworth fourth-order low-pass filter 33 and the ADC input terminal of the sampling chip 7. When the vibration signal amplitude is too large and may exceed the ADC input range, attenuator 35 attenuates the signal by a fixed ratio. Attenuation by attenuator 35 expands the dynamic range acquisition capability of the vibration signal, preventing strong impacts or high-amplitude vibration signals from causing ADC input saturation or damage, ensuring effective acquisition under large signal conditions. Simultaneously, by rationally designing the attenuation ratio, even small signals can fully utilize the ADC resolution, reducing quantization errors.

[0038] Reference Figure 1 As shown, in some embodiments, the self-test circuit 4 includes a proportional voltage divider circuit 41, a first voltage follower 42, and an impedance matching circuit 43. The input terminal of the proportional voltage divider circuit 41 is electrically connected to the cathode of the temperature compensation diode 2, the input terminal of the first voltage follower 42 is electrically connected to the output terminal of the proportional voltage divider circuit 41, the input terminal of the impedance matching circuit 43 is electrically connected to the output terminal of the first voltage follower 42, and the output terminal of the impedance matching circuit 43 is electrically connected to the first input terminal of the multiplexer 6.

[0039] In this embodiment, the proportional voltage divider circuit 41 divides the voltage from the cathode of the stable temperature compensation diode 2 to generate a stable DC reference voltage or a specific waveform. The first voltage follower 42 provides high input impedance and low output impedance, isolating the voltage divider circuit from the subsequent stages. The impedance matching circuit 43 matches its output impedance to the input impedance of the multiplexer 6 and the sampling chip 7. The self-test circuit 4 generates a known and stable verification signal. The main control module 8 controls the multiplexer 6 to select the self-test circuit 4, and the sampling chip 7 acquires the verification signal and compares it with a preset threshold. This accurately determines whether the entire path from the cathode of the temperature compensation diode 2, through the self-test circuit 4, the multiplexer 6, to the sampling chip 7 is functioning correctly. Voltage following and impedance matching ensure the accuracy and stability of the verification signal during transmission, making the self-test results more reliable.

[0040] Reference Figure 1 As shown, in some embodiments, the temperature sampling circuit 5 includes a second voltage follower 52, the input of which is electrically connected to the output of the temperature sensor 51, and the output of which is electrically connected to the second input of the multiplexer 6.

[0041] In this embodiment, since the output impedance of the temperature sensor 51 may be high, direct connection to the multiplexer 6 may lead to measurement errors due to load effects. The second voltage follower 52 serves as impedance transformation and isolation, reducing the impact on the temperature sensor 51 with its high input impedance, and driving the subsequent multiplexer 6 and sampling chip 7 with its low output impedance, thus ensuring the accuracy of temperature signal acquisition.

[0042] Reference Figure 1 As shown, in some embodiments, the temperature sampling circuit 5 includes a TVS protection diode 53, one end of which is electrically connected to the output terminal of the temperature sensor 51, and the other end of which is electrically connected to the input terminal of the second voltage follower 52.

[0043] In this embodiment, the TVS protection diode 53 can suppress instantaneous high-voltage pulses or electrostatic discharges introduced from the leads of the temperature sensor 51, clamping abnormal voltages within a safe range, protecting the precision second voltage follower 52 and the input port of the sampling chip 7 from surge damage, and improving the reliability of the temperature acquisition channel.

[0044] Reference Figure 1 As shown, in some embodiments, the temperature sampling circuit 5 includes a second common-mode inductor 54, the input terminal of which is electrically connected to the other end of the TVS protection diode 53, and the output terminal of which is electrically connected to the input terminal of the second voltage follower 52.

[0045] In this embodiment, the second common-mode inductor 54 further filters out common-mode interference that may be introduced during the long-distance transmission of the temperature sensor 51. Working in conjunction with the TVS protection diode 53, it not only copes with transient high-voltage impacts but also suppresses continuous common-mode noise, providing a "cleaner" signal environment for temperature measurement.

[0046] Reference Figure 1 As shown, in some embodiments, the temperature sampling circuit 5 includes a low-pass filter circuit 55, the input terminal of which is electrically connected to the output terminal of the second common-mode inductor 54, and the output terminal of which is electrically connected to the input terminal of the second voltage follower 52.

[0047] In this embodiment, the temperature signal typically changes slowly, and the high-frequency components are mostly noise. The low-pass filter circuit 55 can effectively filter out high-frequency interference and smooth the signal, reducing the noise level during sampling, thereby improving the resolution and stability of temperature measurement and enabling even minute temperature changes to be accurately captured.

[0048] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A multi-sensor synchronous acquisition circuit, characterized in that, include: Temperature compensation diode (2), the anode of which is used to be electrically connected to the output terminal of constant current source (1); The vibration sampling circuit (3) includes a vibration sensor (31), the input terminal of which is electrically connected to the cathode of the temperature compensation diode (2); Self-test circuit (4), the input terminal of which is electrically connected to the cathode of the temperature compensation diode (2); The temperature sampling circuit (5) includes a temperature sensor (51), the input terminal of which is electrically connected to the cathode of the temperature compensation diode (2). Multiplexer (6), the first input terminal of the multiplexer (6) is electrically connected to the output terminal of the self-test circuit (4), and the second input terminal of the multiplexer (6) is electrically connected to the output terminal of the temperature sensor (51); The sampling chip (7) is electrically connected to the output of the vibration sensor (31) and the output of the multiplexer (6). The main control module (8) is electrically connected to the output of the sampling chip (7).

2. The multi-sensor synchronous acquisition circuit according to claim 1, characterized in that, The vibration sampling circuit (3) includes a high-pass filter (32), the input terminal of which is electrically connected to the output terminal of the vibration sensor (31), and the output terminal of which is electrically connected to the input terminal of the sampling chip (7).

3. The multi-sensor synchronous acquisition circuit according to claim 2, characterized in that, The vibration sampling circuit (3) includes a Butterworth fourth-order low-pass filter (33), the input terminal of which is electrically connected to the output terminal of the high-pass filter (32), and the output terminal of which is electrically connected to the input terminal of the sampling chip (7).

4. The multi-sensor synchronous acquisition circuit according to claim 3, characterized in that, The vibration sampling circuit (3) includes a first common-mode inductor (34), the input terminal of the first common-mode inductor (34) is electrically connected to the output terminal of the vibration sensor (31), and the output terminal of the first common-mode inductor (34) is electrically connected to the input terminal of the high-pass filter (32).

5. The multi-sensor synchronous acquisition circuit according to claim 4, characterized in that, The vibration sampling circuit (3) includes an attenuator (35), the input of which is electrically connected to the output of the Butterworth fourth-order low-pass filter (33), and the output of which is electrically connected to the input of the sampling chip (7).

6. The multi-sensor synchronous acquisition circuit according to claim 1, characterized in that, The self-test circuit (4) includes a proportional voltage divider circuit (41), a first voltage follower (42), and an impedance matching circuit (43). The input terminal of the proportional voltage divider circuit (41) is electrically connected to the cathode of the temperature compensation diode (2). The input terminal of the first voltage follower (42) is electrically connected to the output terminal of the proportional voltage divider circuit (41). The input terminal of the impedance matching circuit (43) is electrically connected to the output terminal of the first voltage follower (42). The output terminal of the impedance matching circuit (43) is electrically connected to the first input terminal of the multiplexer (6).

7. The multi-sensor synchronous acquisition circuit according to any one of claims 1 to 6, characterized in that, The temperature sampling circuit (5) includes a second voltage follower (52), the input terminal of which is electrically connected to the output terminal of the temperature sensor (51), and the output terminal of which is electrically connected to the second input terminal of the multiplexer (6).

8. The multi-sensor synchronous acquisition circuit according to claim 7, characterized in that, The temperature sampling circuit (5) includes a TVS protection diode (53), one end of which is electrically connected to the output terminal of the temperature sensor (51), and the other end of which is electrically connected to the input terminal of the second voltage follower (52).

9. The multi-sensor synchronous acquisition circuit according to claim 8, characterized in that, The temperature sampling circuit (5) includes a second common-mode inductor (54), the input terminal of which is electrically connected to the other end of the TVS protection diode (53), and the output terminal of which is electrically connected to the input terminal of the second voltage follower (52).

10. The multi-sensor synchronous acquisition circuit according to claim 9, characterized in that, The temperature sampling circuit (5) includes a low-pass filter circuit (55), the input terminal of which is electrically connected to the output terminal of the second common-mode inductor (54), and the output terminal of which is electrically connected to the input terminal of the second voltage follower (52).

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