Digital multi-sensor

Abstract

FIELD: non-destructive testing.SUBSTANCE: invention relates to devices for diagnostics of industrial equipment, vibration monitoring and vibration diagnostics systems. The digital multisensor comprises a housing 1, a printed circuit board 2 of sensors, a printed circuit board 3 of controllers and a printed circuit board 4 of interfaces, wherein the printed circuit board 2 of sensors comprises a vibration measurement unit 5, a temperature measurement unit 6, an interface unit 7, wherein the printed circuit board of controllers comprises a central processing unit 9 and an interface unit 10, wherein the central processing unit 9 comprises a microprocessor 11, a memory unit 12, wherein the printed circuit board of interfaces comprises an interface unit 13 of the UART protocol and an interface unit 14 of the RS485 protocol.EFFECT: high-precision measurement and detailed spectral analysis of vibration and temperature characteristics of industrial equipment, which allows for increased diagnostic accuracy, early detection of defects through the analysis of one-third octave spectra when the integral characteristics are still within normal limits, reduced cost of the control system, reduced installation and setup time, increased calibration intervals, expanded scope of application to hazardous areas, and long-term operation in harsh conditions.2 cl, 1 dwg

Description

[0001] Application area

[0002] Devices for non-destructive testing and diagnostics of industrial equipment, vibration monitoring and vibration diagnostics systems, automated process control systems.

[0003] Technology Level

[0004] A device for monitoring the temperature and vibration of electrical machinery equipment, RU 2804260 C1 (Ruselprom Engineering Center LLC), was published on September 26, 2023. The device consists of a housing with connectors for temperature and vibration sensors. The device's drawbacks include insufficient accuracy and quality of the resulting information due to the use of suboptimal hardware and information processing tools.

[0005] There are also a significant number of technical solutions in the field of vibration and temperature sensors (patents WO2020134890, CN117589215, CN214666996, CN213336244, CN112161726, RU2827924, etc.). Known solutions have the following limitations:

[0006] 1. Functional limitations: existing sensors either only measure integral vibration characteristics without spectral analysis (RU2827924, CN214666996), or require external equipment for detailed diagnostics.

[0007] 2. Lack of built-in spectral analysis: none of the identified analogs provide calculation of one-third-octave vibration spectra directly in the sensor.

[0008] 3. Low integration: In most solutions, the vibration and temperature modules are not functionally integrated, which leads to increased dimensions and complicated installation (CN117589215, CN219573129);

[0009] 4. Limited accuracy: The measurement error of known solutions is ±10% or higher (CN112067059, RU2654996).

[0010] Disclosure of the essence of the invention

[0011] The invention considers a compact, high-precision digital multisensor that provides, in a single housing, simultaneous measurement of vibration and temperature characteristics of industrial equipment with the possibility of detailed spectral analysis directly in the multisensor, without the use of external equipment, ensuring high metrological accuracy, protection from aggressive operating conditions and the possibility of use in explosive areas.

[0012] Integrated dual-module digital multi-sensor, combines in a single sealed stainless steel housing (30×22×30 mm, IP68 protection rating) two completely independent but complementary measuring modules (vibration measuring module and temperature measuring module) and an integrated control system.

[0013] Vibration measurement module contains:

[0014] Three-axis microelectromechanical (MEMS) accelerometer (MEMS accelerometer) IIS3DWBTR (±16 g, up to 6 kHz, 26.7 kHz sampling)

[0015] Built-in 3KB FIFO buffer for continuous data acquisition

[0016] Digital processing system based on a 32-bit ARM Cortex-M4F processor (120 MHz) with the ability to calculate one-third octave spectra in the range of 10-10,000 Hz and calculate derivative parameters using the sequential integration method.

[0017] Temperature measurement module contains:

[0018] Digital sensor AT30TSE758A-MA8M-T (accuracy ±0.5°C, resolution 9-12 bits, measurement range: -40...+80°C with a resolution of 0.1°C)

[0019] ALERT alarm when thresholds are exceeded

[0020] Integrated control system contains:

[0021] Modular three-board design with functional separation

[0022] 64 Mbit RAM + 16 Mbit non-volatile memory

[0023] Embedded RTOS firmware with asynchronous module operation

[0024] Modbus RTU protocol via RS485 (up to 1 km)

[0025] Comprehensive protection system for explosion-proof design.

[0026] Unlike known solutions, the declared multisensor is characterized by the following new features:

[0027] 1. Two-module architecture with complete functional independence of vibration and temperature modules (sensors) in a single compact 30×22×30 mm housing;

[0028] 2. Built-in calculation of one-third octave spectra directly in the multisensor in the range of 10-10000 Hz;

[0029] 3. Three-stage digital processing system with sequential integration for calculating vibration velocity and vibration displacement based on vibration acceleration;

[0030] 4. Original modular design of three boards (sensor board - controller board - interface board) with detachable connections, which ensures the minimization of electromagnetic interference and manufacturability.

[0031] 5. High metrological accuracy: the measurement error of the RMS vibration velocity is ±6.0% (1.5-2 times better than that of analogues), temperature is ±0.5°C, additional temperature error is only ±0.02% per 1°C;

[0032] 6. Comprehensive self-diagnostic system with three-color LED indication and a detailed status log, allowing you to monitor the performance of both modules.

[0033] Advantages over known solutions:

[0034] 1. Comprehensive diagnostics without external equipment - a multisensor replaces the combination of a traditional sensor and spectrum analyzer;

[0035] 2. Compact - volume 19.8 cm 3 with full functionality, which is 3-4 times less than similar systems;

[0036] 3. Accuracy - the measurement error is 1.5-2 times lower than that of known solutions, thanks to built-in temperature compensation and high-performance processing.

[0037] 4. Versatility - a single multi-sensor for vibration monitoring, vibration diagnostics, and temperature control, which reduces the cost of the control system by 2-3 times.

[0038] 5. Early diagnostics - one-third octave spectra allow for the detection of defects at a stage when they are not yet reflected in the integral characteristics (30-40% earlier).

[0039] 6. Safety - explosion-proof design expands the areas of application (chemical, mining industries);

[0040] 7. Durability - 10 years service life, 93,000 hours MTBF due to the elimination of electrolytic capacitors and the use of industrial components.

[0041] Technical result:

[0042] The integrated dual-module multi-sensor provides, in a single compact housing, simultaneous high-precision measurement and detailed spectral analysis of the vibration and temperature characteristics of industrial equipment, which allows for: increased diagnostic accuracy, early detection of defects by analyzing one-third octave spectra when the integral characteristics are still within normal limits, reduced cost of the control system, reduced installation and setup time, increased calibration intervals, expanded application scope to explosive zones, and ensured long-term operation in harsh conditions.

[0043] The claimed technical result is achieved by implementing a digital multisensor containing a housing 1, a printed circuit board 2 of sensors, a printed circuit board 3 of controllers and a printed circuit board 4 of interfaces, wherein the printed circuit board 2 of sensors contains a vibration measurement unit 5, a temperature measurement unit 6, an interface unit 7,

[0044] wherein the controller printed circuit board contains a central processing unit 9 and an interface unit 10, wherein the central processing unit 9 contains a microprocessor 11, a memory unit 12,

[0045] wherein the printed circuit board of interfaces comprises an interface unit 13 of the UART protocol and an interface unit 14 of the RS485 protocol, wherein the output of the vibration measurement unit 5 is connected to the interface unit 7 of the sensor printed circuit board, the temperature measurement unit 6 is connected to the interface unit 7 of the sensor printed circuit board, the output of the interface unit 7 of the sensor printed circuit board is connected to the interface unit 10 of the controller printed circuit board, the output of the interface unit 10 of the controller printed circuit board is connected to the central processing unit 9 and to the interface unit 13 of the interface printed circuit board and the interface unit 14 of the interface printed circuit board, wherein the memory unit 12 is connected to the microprocessor 11, wherein the memory unit 12 contains a program code and when the microprocessor 11 executes the program code, the operations of filtering, calibration, spectral analysis using the fast Fourier transform (FFT), aggregation of amplitudes from the FFT into one-third octave bands and calculations are performed RMS amplitudes for each band.

[0046] In one of the possible embodiments, the housing 1 is made sealed.

[0047] Brief description of drawings

[0048] Fig. 1 shows the structural diagram of a digital multisensor.

[0049] The digital multisensor comprises a housing 1, a printed circuit board 2 of sensors, a printed circuit board 3 of controllers and a printed circuit board 4 of interfaces, wherein the printed circuit board 2 of sensors contains a vibration measurement unit 5, a temperature measurement unit 6, an interface unit 7, the printed circuit board of controllers contains a central processing unit 9 and an interface unit 10, the central processing unit 9 contains a microprocessor 11, a memory unit 12,

[0050] The interface printed circuit board contains the UART protocol interface unit 13 and the RS485 protocol interface unit 14.

[0051] Fig. 2 shows the structural diagram of the sensor board.

[0052] Fig. 3 shows the structural diagram of the controller board.

[0053] Fig. 4 shows the structural diagram of the interface board.

[0054] Fig. 5 shows the block diagram of the vibration measurement module.

[0055] Implementation of the invention

[0056] The following description provides a more detailed disclosure of the invention, which provides examples of the structural implementation of the elements disclosed in the structural diagram in Fig. 1, in particular the structural implementation of the printed circuit board 2 of sensors (Fig. 2), the printed circuit board 3 of controllers (Fig. 3) and the printed circuit board 4 of interfaces (Fig. 4).

[0057] The interface board is designed to provide communication via the RS485 interface and interact with the main board via a connector

[0058] Functional Blocks

[0059] Power supply

[0060] • Input voltage: +18-36V DC

[0061] • Primary stabilizer (DA2): The K7805MT-500R4 microcircuit converts the input voltage to +5V to power intermediate circuits

[0062] • Secondary stabilizer (DA3): The ADP150AUJZ-3.3-R7 microcircuit generates a voltage of +3.3V to power the logic circuits and the interface microcircuit

[0063] • Filtering elements: Capacitors C1 (10 μF), C2 (22 μF), C3-C8 (0.1-1 μF) provide smoothing and filtering of supply voltages

[0064] Protection Block

[0065] • Fuse FA1 (1206L025YR): Input power supply circuit overcurrent protection

[0066] • FA2 Protection Device (TBU-RS055-300-WH): Protection of RS485 interface lines from overvoltage and impulse noise

[0067] • TVS diode VD1 (P4SMA36CA): Power input protection from surge voltage

[0068] • Diode VD2 (SS16): Power supply reverse polarity protection

[0069] • Zener diode VD3 (PTZTFTE255.6B): Additional voltage stabilization

[0070] RS485 interface unit

[0071] • Transceiver DD1 (ADM3062EACPZ-R7): The main chip for converting UART signals into differential RS485 signals (lines A and B)

[0072] • Termination resistors: R2 (390 Ohm), R3 (3 kOhm) provide matching of communication lines

[0073] • External connections: Contact holes for soldering wires of external cable RS485 A, RS485 B, GND, BOOT IN, +5V

[0074] UART interface block

[0075] • Signals to the main board: GP_UART_RX, GP_UART_TX, GP_UART_RX_EN, GP_UART_TX_EN provide bidirectional communication with the microcontroller

[0076] • Additional control signals: WDT_KICK (watchdog timer reset), MCU_RESET (microcontroller reset), BOOT_EN (boot mode)

[0077] Optical Isolator Block

[0078] • Optocoupler U1 (SFH690BT): provides galvanic isolation of the BOOT_EN signal between the power and logic parts of the board

[0079] • Current limiting resistors: R1 (10 kOhm), R4 (470 Ohm) set the currents through the optocoupler LED

[0080] Indication unit

[0081] • VD4 (KR-2012SYCK): Yellow LED for status indication

[0082] • VD5 (KR-2012QBC-D): Red LED for indicating errors or emergency modes

[0083] • VD6 (LTST-C235KGKRKT): Green LED for normal operation indication

[0084] • Current-limiting resistors: R5 (1.6 kOhm), R6 (470 Ohm), R7 (510 Ohm) limit the current through the LEDs

[0085] Connection block

[0086] • Connector X1 (2049270201): 20-pin connector for connection to the main board with mounting contacts MNT1-MNT4

[0087] Block Interaction

[0088] The input voltage passes through a protection block to the power supply, which generates stabilized +5V and +3.3V voltages. The DD1 transceiver converts UART signals from the main board into differential RS485 signals for transmission over long communication lines. An optocoupler ensures safe boot mode control, and LEDs indicate the current device status.

[0089] The sensor board is a combined vibration and temperature measurement module containing the following functional blocks:

[0090] Vibration measurement unit

[0091] • The DD2 accelerometer (IIS3DWBTR) is a three-axis digital vibration sensor with a wide frequency band. Main features: measurement range of ±2 / ±4 / ±8 / ±16 g, bandwidth up to 6 kHz, sampling frequency of 26.7 kHz, built-in 3 KB FIFO buffer. Connection interface: SPI (signals ACC_SPI_SCK, ACC_SPI_MOSI, ACC_SPI_MISO, ACC_SPI_CS) and two interrupt lines (ACC_IRQ1, ACC_IRQ2).

[0092] Temperature measurement unit

[0093] • Temperature sensor DD1 (AT30TSE758A-MA8M-T) - digital temperature sensor with an accuracy of ±0.5°C and a resolution of 9-12 bits. Connection interface: I2C (signals I2C_SDA, I2C_SCL) with an additional ALERT line for signaling when temperature thresholds are exceeded

[0094] Power supply and filtration unit

[0095] • +3.3 V power supply system with decoupling capacitors C1, C2, C3 (0.1 μF each) to filter interference in the power supply circuits of the DD1 and DD2 microcircuits.

[0096] Interface block

[0097] X1 connector (687310124422) for connecting to the main board. Pull-up resistors R1-R4 (10 kOhm) ensure the stability of the I2C signal lines and control signals.

[0098] Working principle

[0099] The device operates as follows: the main board supplies +3.3V power to the sensor board via the X1 connector. The DD2 accelerometer continuously measures vibration acceleration along three axes and transmits digital data via the SPI interface, using a built-in FIFO buffer to prevent data loss at high sampling rates. The DD1 temperature sensor simultaneously measures temperature and transmits data via the I2C interface, generating a signal on the ALERT line when preset temperature thresholds are exceeded. Both devices operate independently, exchanging data with the central controller on the main board via their respective interfaces.

[0100] Design

[0101] The board is manufactured using a four-layer FR4 printed circuit board with a thickness of 1.13 mm and a precision class of 4. The board dimensions are 23.6 x 7.0 mm and weighs 0.003 kg. It uses a combined positive-pressure manufacturing method with a POS-61 finish.

[0102] The controller board contains:

[0103] Central processing unit

[0104] • The DD3 microcontroller (ATSAME53J20A-AU) is a 32-bit ARM Cortex-M4F processor with a frequency of up to 120 MHz, 1024 KB of flash memory, and 256 KB of SRAM. It provides central control of all device functions. The microcontroller has an integrated FPU for floating-point calculations, peripherals for working with I2C, SPI, and UART interfaces, and support for programming via SWD.

[0105] Memory Block

[0106] • Volatile memory DD1 (ESP-PSRAM64H) - 64 Mbit (8 MB) pseudo-SRAM with SPI / QPI interface and a maximum frequency of 133 MHz, used to store intermediate data.

[0107] • Non-volatile memory DD2 (SST26VF016B) - 16 Mbit flash memory with SPI interface for long-term storage of data and configurations.

[0108] Power and control unit

[0109] • Voltage supervisor DA1 (MAX6747KA29+T) monitors the +3.3V power supply with a threshold of 2.925V, generates a reset signal MCU_RESET when the voltage drops below the threshold and ensures correct system start.

[0110] • Inductor L1 (LQH32CN100K33L) and capacitors C1-C16 (10nF to 10μF) provide filtering and power supply stabilization at various levels of the circuit.

[0111] Interface block

[0112] • Connector X1 (54550-1071) provides connection to the board and includes UART lines (GP_UART_RX, GP_UART_TX with direction control), watchdog timer (WDT_KICK), programming interface (SWDIO, SWCLK) and control signals.

[0113] • Connector X2 (2049280201) provides connection to the board via SPI (for accelerometer), I2C and accelerometer interrupt pins (ACC_IRQ1, ACC_IRQ2).

[0114] Synchronization block

[0115] • The ZQ1 resonator (ASEK-32.768KHZ-LRT) provides low-frequency clocking for the microcontroller's low-power modes and real-time clock.

[0116] Pull-up and matching unit

[0117] • Resistor assemblies R1, R17-R18, R20-R21, R31-R32 (EXB-28V103JX) and individual resistors R2-R30 (from 0 Ohm to 10 kOhm) provide pull-up of signal lines to the +3.3V level, formation of reference voltages and coordination of logical levels of interfaces.

[0118] Working principle

[0119] The circuit implements a multifunctional controller with advanced data processing capabilities, external memory support and multiple communication interfaces for integration into a distributed control system.

[0120] D&M digital industrial multi-sensor has explosion protection type "intrinsically safe electrical circuit" i ".

[0121] To prevent ignition, the internal volume of the multi-sensor is filled with compound.

[0122] A self-resetting fuse is installed in the power supply circuit.

[0123] Current-limiting resistors are installed in the RS-485 interface circuits.

[0124] Data processing.

[0125] General process flow chart (Fig. 5)

[0126] 1. MEMS sensor → Analog signal → Analog digital converter

[0127] 2. Analog to Digital Converter → Digital Signal.

[0128] Further processing is carried out by specialized software on a microcontroller that receives data and implements the following functions:

[0129] • Pre-treatment: Filtration, calibration.

[0130] • Spectral analysis: Fast Fourier transform (FFT) → Signal spectrum.

[0131] • Band Aggregation: Aggregate amplitudes from FFT into one-third octave bands.

[0132] • Normalization and presentation: Calculate RMS amplitude for each band.

[0133] The vibration sensor's sensing element (part of the multisensor) is a microelectromechanical system (hereinafter referred to as MEMS) on a silicon crystal. It converts mechanical vibrations along the X, Y, and Z axes into electrical signals, which are then digitized by a three-channel analog-to-digital converter. The sensor's built-in microprocessor reads vibration signals along three axes and, using a digital processing algorithm, calculates integral vibration signal characteristics such as RMS vibration acceleration, RMS vibration velocity, RMS vibration displacement, peak-to-peak amplitude, peak factor, and frequency with maximum amplitude.

[0134] The values ​​of these characteristics in SI physical units are regularly updated in internal registers, which can be read via the Modbus RTU protocol. The sensor's settings and calibration parameters are stored in non-volatile memory and can be read and modified using the service software.

[0135] The multisensor also monitors the surface temperature of the monitored equipment. The current temperature value is displayed in the corresponding Modbus RTU register.

[0136] A specialized digital vibration signal processing system implemented using a microprocessor provides the following operations:

[0137] Fast Fourier Transform (FFT) for spectral analysis with resolution up to 10,000 Hz,

[0138] Successive integration to calculate vibration velocity (single) and vibration displacement (double) based on the original vibration acceleration signal

[0139] Calculation of amplitudes in one-third octave frequency bands in the range of 10-10,000 Hz

[0140] Calculation of integral characteristics: RMS vibration acceleration, RMS vibration velocity (0.3-218.0 mm / s), RMS vibration displacement, signal amplitude, peak factor, frequency with maximum amplitude.

[0141] The algorithm processes the discrete FFT spectrum, aggregating the energy contribution (the sum of the squares of the amplitudes) from all frequency components that fall within the boundaries of the standard one-third octave bands.

[0142]

[0143] In the above description, embodiments of the present invention are set out for clarity with reference to specific circuits and blocks and with an indication of a variant of the structural arrangement of elements on individual boards.

[0144] Note that any suitable distribution of functionality between different design boards, circuits, or blocks may be used without prejudice to the present invention.

[0145] For example, the illustrated functionality, to be implemented by individual blocks, may be implemented by the same block, and the individual blocks may be structurally arranged on one or more boards. Therefore, references to specific functional blocks or circuits should be considered only as references to suitable means for providing the described functionality, and not as an indication of a strict logical or physical structure of the system.

[0146] The present invention may be implemented in any suitable form, including hardware, software, or any combination thereof. Although the present invention has been described in connection with certain embodiments, this should not be construed as limiting it to the specific form set forth herein. Rather, the scope of the present invention is limited only by the appended claims.

[0147] Taking into account the above, it can be concluded that the essential features of the claimed invention are not known from the prior art and ensure full compliance of the claimed invention with the patentability conditions of “novelty” and “inventive step”.

[0148] The claimed invention can be used in industry and fully satisfies the patentability condition of “industrial applicability”.

[0149] It follows that, in the opinion of the applicant, the claimed invention fully complies with the conditions of patentability according to Article 1350 of the Civil Code of the Russian Federation.

Claims

1. A digital multisensor comprising a housing (1), a printed circuit board (2) of sensors, a printed circuit board (3) of controllers and a printed circuit board (4)) of interfaces, wherein the printed circuit board (2) of sensors contains a vibration measurement unit (5), a temperature measurement unit (6), an interface unit (7), wherein the printed circuit board of the controllers contains a central processing unit (9) and an interface unit (10), wherein the central processing unit (9) contains a microprocessor (11), a memory unit (12), wherein the interface printed circuit board contains an interface unit (13) of the UART protocol and an interface unit (14) of the RS485 protocol, wherein the output of the vibration measuring unit (5) is connected to the interface unit (7) of the printed circuit board of sensors, the temperature measuring unit (6) is connected to the interface unit (7) of the printed circuit board of sensors, the output of the interface unit (7) of the printed circuit board of sensors is connected to the interface unit (10) of the printed circuit board of controllers, the output of the interface unit (10) of the printed circuit board of controllers is connected to the central processing unit (9) and to the interface unit (13) of the printed circuit board of interfaces and the interface unit (14) of the printed circuit board of interfaces, wherein the memory unit (12) is connected to the microprocessor (11), wherein the memory unit (12) contains a program code and when the microprocessor (11) executes the program code, the operations of filtering, calibration, spectral analysis using the fast Fourier transform (FFT), aggregation of amplitudes from the FFT into one-third octave bands and calculation of the RMS amplitude for each band are performed.

2. A multisensor according to claim 1, characterized in that the housing (1) is made sealed.

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