Digital output vibration sensor

Abstract

The utility model discloses a digital output vibration sensor, which comprises an accelerometer, a channel switching module, a multipath signal amplification module and an ADC sampling module which are connected in sequence, the multipath signal amplification module comprises signal amplifiers which are in one-to-one correspondence with channels in the channel switching module, the amplification factors of the signal amplifiers are different, and the ADC sampling module is connected with the accelerometer. The accelerometer is connected with the input end of each channel in the channel switching module, and the output end of each channel in the channel switching module is connected with the ADC sampling module through the corresponding signal amplifier. According to the utility model, digital signals can be directly output, and the measuring range is wide.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, in particular to a vibration sensor with digital output. Background Art

[0002] A vibration sensor is a device or equipment used to detect and measure the vibration or shock of an object. It can convert the mechanical energy of the object's vibration into a corresponding electrical signal for analysis, monitoring and control.

[0003] Because vibration sensors need to measure vibration signals, the signal vibration intensity varies greatly and the signal bandwidth is large. In order to avoid the problem of large transmission bandwidth caused by large signal bandwidth and difficulty in transmission through the field bus, existing vibration sensors mostly use analog signal output. After the back-end host computer or computing unit obtains the analog signal, it will digitize and process the data. However, analog signals have high requirements for external factors such as transmission signal lines, transmission distances, and test environments. Utility Model Content

[0004] The technical problem to be solved by the utility model is: in view of the technical problems existing in the prior art, the utility model provides a vibration sensor with digital output, which can directly output digital signals and has a wider measurement range.

[0005] In order to solve the above technical problems, the technical solution proposed by the utility model is:

[0006] A vibration sensor with digital output comprises an accelerometer, a channel switching module, a multi-channel signal amplification module and an ADC sampling module which are connected in sequence. The multi-channel signal amplification module comprises a signal amplifier corresponding to each channel in the channel switching module, and the amplification factor of each signal amplifier is different. The accelerometer is connected to the input end of each channel in the channel switching module, and the output end of each channel in the channel switching module is connected to the ADC sampling module through the corresponding signal amplifier.

[0007] Furthermore, a communication module is included, and the output end of the ADC sampling module is connected to a host computer via the communication module.

[0008] Preferably, the channel switching module adopts a multiplex switch, the input end of the multiplex switch is connected to the accelerometer, the output end of the multiplex switch is respectively connected to the corresponding signal amplifier, and the control end of the multiplex switch is connected to the host computer through the communication module.

[0009] Preferably, the output end of the signal amplifier is connected to the ADC sampling module via a coupling capacitor and a voltage divider circuit in sequence.

[0010] Preferably, the signal amplifiers all use common-phase operational amplifiers, the inverting input terminal of each common-phase operational amplifier is connected to the reference power supply through a corresponding first resistor, the output terminal of each common-phase operational amplifier is connected to the inverting input terminal through a corresponding feedback resistor, and the ratio of the first resistor and the feedback resistor of each common-phase operational amplifier is different.

[0011] Preferably, the signal amplifiers all adopt inverting operational amplifiers, the inverting input terminal of each inverting operational amplifier is connected to the output terminal of the corresponding channel in the channel switching module through the corresponding second resistor, the output terminal of each inverting operational amplifier is connected to the inverting input terminal through the corresponding feedback resistor, and the ratio of the second resistor and the feedback resistor of each inverting operational amplifier is different.

[0012] Preferably, the channel switching module adopts a switch group, and the input end of each signal amplifier is connected to the output end of the accelerometer through a corresponding switch in the switch group.

[0013] Preferably, the switch is a push button switch or a dip switch.

[0014] Preferably, the ADC sampling module adopts an AD converter.

[0015] Preferably, the communication module adopts an RS485 module.

[0016] Compared with the prior art, the advantages of the utility model are:

[0017] 1. The accelerometer is connected in sequence through the channel switching module, the multi-channel signal amplification module and the ADC sampling module, so as to convert the vibration signal detected by the accelerometer from an analog signal to a digital signal. Since the output is digital information, there is no influence of factors such as transmission line, transmission distance, and transmission environment in the process of analog signal transmission;

[0018] 2. Each channel of the channel switching module is respectively connected to signal amplifiers with different amplification factors in the multi-channel signal amplification module. According to actual needs, a suitable signal amplifier can be selected to amplify the vibration signal detected by the accelerometer to the required magnification, thereby improving the measurement range and applicability of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural block diagram of an embodiment of the utility model.

[0020] Figure 2 Schematic diagram of the channel selection module structure of an embodiment of the utility model.

[0021] Figure 3 This is a circuit schematic diagram of a signal amplifier according to an embodiment of the utility model.

[0022] Legend: 1-accelerometer, 2-channel switching module, 3-multi-channel signal amplification module, 4-ADC sampling module, 5-communication module, 6-host computer, 31-signal amplifier. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0024] With the development of modern industry, ship equipment is getting bigger and more complex, and the resulting vibration and noise problems are becoming more and more prominent. However, these vibrations are extremely harmful in most cases. Ship power equipment, such as the connecting bearings of the engine, will deform and wear under long-term vibration conditions, and these deformations and wear will produce greater vibrations and noise, seriously affecting their service life and even causing accidents. Therefore, it is necessary to monitor the vibration of ship equipment in real time to detect and solve problems as early as possible.

[0025] This embodiment proposes a vibration sensor with digital output, which can be applied to a variety of vibration detection scenarios, including but not limited to ship vibration detection. The vibration sensor is based on an accelerometer. Accelerometer-based vibration sensors have become the mainstream of vibration sensors due to their ease of mass production and good consistency. Ship vibration detection has a wide range of signal vibration intensity variations and a large signal bandwidth. In order to enable the vibration sensor to adapt to the detection of a wide range of vibration intensities, a multi-channel signal amplification path is used to adapt to different vibration intensities to avoid sensor overload or the problem of the signal being too small to measure.

[0026] Based on the above concept, Figure 1 As shown, the vibration sensor of this embodiment includes an accelerometer 1, a channel switching module 2, a multi-channel signal amplification module 3, an ADC sampling module 4 and a communication module 5 connected in sequence, the multi-channel signal amplification module 3 includes a signal amplifier 31 corresponding to each channel in the channel switching module 2, and the amplification factor of each signal amplifier 31 is different. The accelerometer 1 is connected to the input end of each channel in the channel switching module 2, and the output end of each channel in the channel switching module 2 is connected to the ADC sampling module 4 through the corresponding signal amplifier 31, and the output end of the ADC sampling module 4 is connected to the host computer 6 through the communication module 5.

[0027] Through the above structure, the accelerometer 1 is used as a front-end signal sensing device to detect vibration signals. Since the inherent measurement accuracy and noise level of the accelerometer 1 are fixed, multiple signal amplifiers 31 in the multi-channel signal amplification module 3 are designed according to their corresponding performance indicators, and a channel switching module 2 is set to switch the specified channel. The vibration signal passes through the specified channel in the channel switching module 2 to reach the corresponding signal amplifier 31 in the multi-channel signal amplification module 3 for amplification, and then enters the ADC acquisition module 4 for data acquisition. The host computer 6 can obtain the digital signal for subsequent processing.

[0028] In this embodiment, the amplification factor of the signal amplifier 31 can be set according to actual needs. For example, the amplification factor is set to 1 / N, 1 / N-1, ..., 1, 2, ..., N for a total of 2N signal amplifiers 31. When the vibration signal received by the host computer 6 is very weak, the channel switching module 2 can be used to switch to the channel corresponding to the signal amplifier 31 that amplifies N times to amplify the signal, thereby ensuring that small signals can also be detected; when the vibration signal received by the host computer 6 is too large and exceeds the measurement range of the sensor, the channel switching module 2 can be used to switch to the channel corresponding to the signal amplifier 31 that is reduced by N times (amplified by 1 / N times) to reduce the signal, which can ensure that the sensor measurement range is improved within the sensor range and the adaptability of the sensor is improved.

[0029] In this embodiment, the channel switching module 2 can use a multiplex switch to achieve the switching of the corresponding channels of the host computer remote control signal amplifier 31, such as Figure 1 As shown, the input end of the multiplexer switch is connected to the accelerometer 1, the output end of the multiplexer switch is respectively connected to the corresponding signal amplifier 31, and the control end of the multiplexer switch is connected to the host computer 6 through the communication module 5, so that the enable signal or control instruction of the switching channel sent by the host computer 5 reaches the control end of the multiplexer switch through the communication module 5, and the multiplexer switch switches the corresponding channel according to the enable signal or control instruction.

[0030] It should be noted that, in the case where the host computer 6 remotely controls channel switching, in addition to manually operating the host computer 6 to issue control instructions for channel switching, a program can also be written to implement the default situation where the host computer 6 automatically issues instructions to control the multiplexing switch to perform channel switching according to the accelerometer signal characteristics to switch signal amplifiers 31 with different amplification factors in the multi-channel signal amplification module 3.

[0031] In this embodiment, when the channel switching module 2 uses a multiplexing switch, a COMS single-channel 8-channel analog multiplexing switch with CD4051B multi-function conversion is specifically selected to perform channel switching, such as Figure 2As shown, CD4051 has the characteristics of large input voltage range and few input control lines. It can completely shut down the input signal when not detecting, and the 8-channel channel can meet most application environments.

[0032] In this embodiment, the signal amplifier 31 is a common-mode operational amplifier. Figure 3 As shown, the inverting input terminal of each in-phase operational amplifier is connected to the reference power supply through the corresponding first resistor R1, the in-phase input terminal of each in-phase operational amplifier is connected to the output terminal of the corresponding channel in the channel switching module 2, and the output terminal of each in-phase operational amplifier is connected to the inverting input terminal through the corresponding feedback resistor R2, so that the amplification factor is calculated according to the resistors R1 and R2. In this embodiment, the ratio of the first resistor R1 and the feedback resistor R2 of each in-phase operational amplifier is different.

[0033] In this embodiment, the in-phase operational amplifier uses an SGM8049 multi-channel operational amplifier. Figure 3 As shown, the output end of the in-phase operational amplifier is connected to the ADC sampling module 4 through a coupling capacitor C4 and a voltage divider circuit composed of resistors R3 and R4 in sequence, wherein the coupling capacitor is used to filter out the DC component and reduce noise interference, and the voltage divider circuit reduces the output signal amplitude of the in-phase operational amplifier to a suitable level so that it can be effectively processed by the back-end ADC sampling module 4.

[0034] Correspondingly, the signal amplifier 31 in this embodiment can also be an inverting operational amplifier, and its circuit principle is the same as Figure 3 Basically the same, the difference is that the inverting input terminal of each inverting operational amplifier is connected to the output terminal of the corresponding channel in the channel switching module 2 through the corresponding second resistor, the non-inverting input terminal of each inverting operational amplifier is connected to the reference power supply, the output terminal of each inverting operational amplifier is connected to the inverting input terminal through the corresponding feedback resistor, and the ratio of the second resistor and the feedback resistor of each inverting operational amplifier is different.

[0035] In this embodiment, the channel switching module 2 may also use a switch group to realize the switching of the corresponding channels of the local control signal amplifier 31. The input end of each signal amplifier 31 is connected to the output end of the accelerometer 1 through the corresponding switch in the switch group. The operator can switch different channels by switching the on or off state of different switches. Specifically, the switch may use a key switch or a dip switch. In this embodiment, a dip switch is used. The dip switch is easy to identify. A simple dip switch combination can realize various complex function selections, which is convenient for operators to understand at a glance. The switch group uses an 8-bit dip switch to fully meet the switching of various control applications of the sensor.

[0036] In this embodiment, the ADC sampling module 4 adopts an AD converter, specifically a single AD converter is arranged between the multi-channel signal amplification module 3 and the communication module 5. Of course, an AD converter corresponding to the signal amplifier 31 can also be used to realize multi-channel ADC conversion and select appropriate data for processing. However, this will not only increase the power consumption of the circuit, but also increase the sampling load, affect the sampling rate, increase the hardware cost, and place higher requirements on the data processing unit, and the control and processing will be more complicated.

[0037] In this embodiment, the AD converter uses a 4-channel 16-bit AD converter, model AD7682, which communicates through an SPI interface with a fast communication rate, an AD conversion rate of 250KSPS, simple control, and only requires 16 bits of configuration information to obtain the conversion result.

[0038] In this embodiment, the communication module 5 adopts an RS485 module, and the RS485 module uses the RS485 protocol to exchange data with the host computer 5, which can not only improve the output distance, but also solve the interference problem in the transmission process, and facilitate the expansion of the later system.

[0039] In this embodiment, the host computer 6 is configured with a 1 / 3 octave calculation module and an FFT calculation module. The data collected by the accelerometer 1 enters the host computer 6. After the 1 / 3 octave data calculation, the operator determines whether it is necessary to switch to a more accurate FFT calculation based on the calculation results, or directly output the sampled data to calculate the results, and then determine whether there is an abnormality based on these results. If there is an abnormality, an alarm message needs to be output.

[0040] The working principle between the vibration sensor and the host computer of this embodiment is described below.

[0041] 1) Under normal circumstances, the channel switching module 2 is set to switch to the default channel, for example, the channel corresponding to the signal amplifier 31 with an amplification factor of 1. The host computer 5 collects data on the signal of the accelerometer 1 and performs 1 / 3 octave data calculation. If there is no obvious abnormality, no subsequent operation is required.

[0042] 2) If the 1 / 3 octave calculation result shows obvious abnormality, the abnormal information is saved. When the abnormal signal continues, the host computer 5 performs FFT data calculation to obtain accurate positioning of the abnormal frequency and amplitude information, or the host computer 5 directly outputs the sampling signal for calculation, thereby locating the abnormal vibration position and type.

[0043] 3) If the collected signal is too weak (for example, in the case of an abnormality that occurs sometimes but not always, it may be that the signal is too small to be detected), or the collected signal exceeds the set range and subsequent calculations cannot be performed, local manual control or remote command from the host computer is used to control the channel switching module 2 to switch to a more appropriate signal channel, and the signal of the accelerometer 1 is amplified or reduced by the signal amplifier 31 corresponding to the switched channel, and then data sampling is performed through the ADC sampling module 4, and the sampled digital signal data is sent to the host computer 6 through the communication module 5.

[0044] The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form. Although the utility model has been disclosed as a preferred embodiment, it is not used to limit the utility model. Therefore, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the content of the technical solution of the utility model shall fall within the scope of protection of the technical solution of the utility model.

Claims

1. A vibration sensor with digital output, characterized in that: The invention comprises an accelerometer (1), a channel switching module (2), a multi-channel signal amplification module (3) and an ADC sampling module (4) connected in sequence, wherein the multi-channel signal amplification module (3) comprises a signal amplifier (31) corresponding to each channel in the channel switching module (2), and the amplification factor of each signal amplifier (31) is different. The accelerometer (1) is connected to the input end of each channel in the channel switching module (2), and the output end of each channel in the channel switching module (2) is connected to the ADC sampling module (4) through the corresponding signal amplifier (31). The invention also comprises a communication Module (5), the output end of the ADC sampling module (4) is connected to the host computer (6) through the communication module (5), the channel switching module (2) adopts a multiplex switch or a switch group, the input end of the multiplex switch is connected to the accelerometer (1), the output end of the multiplex switch is respectively connected to the corresponding signal amplifier (31), the control end of the multiplex switch is connected to the host computer (6) through the communication module (5), or the input end of each signal amplifier (31) is respectively connected to the output end of the accelerometer (1) through the corresponding switch in the switch group.

2. The vibration sensor with digital output according to claim 1, characterized in that: The output end of the signal amplifier (31) is connected to the ADC sampling module (4) via a coupling capacitor and a voltage divider circuit in sequence.

3. The vibration sensor with digital output according to claim 1, characterized in that: The signal amplifiers (31) all adopt common-phase operational amplifiers, the inverting input terminal of each common-phase operational amplifier is connected to a reference power supply via a corresponding first resistor, the output terminal of each common-phase operational amplifier is connected to the inverting input terminal via a corresponding feedback resistor, and the ratio of the first resistor to the feedback resistor of each common-phase operational amplifier is different.

4. The vibration sensor with digital output according to claim 1, characterized in that: The signal amplifiers (31) all adopt inverting operational amplifiers, the inverting input end of each inverting operational amplifier is connected to the output end of the corresponding channel in the channel switching module (2) via a corresponding second resistor, the output end of each inverting operational amplifier is connected to the inverting input end via a corresponding feedback resistor, and the ratio of the second resistor to the feedback resistor of each inverting operational amplifier is different.

5. The vibration sensor with digital output according to claim 1, characterized in that: The switch is a push button switch or a dial switch.

6. The vibration sensor with digital output according to claim 1, characterized in that: The ADC sampling module (4) adopts an AD converter.

7. The vibration sensor with digital output according to claim 1, characterized in that: The communication module (5) adopts an RS485 module.

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