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Sensor and IO-Link-based predictive maintenance kit based on STM L6362A and STM32F469AI

Время публикации : 2020-02-22 Sensor
Predictive maintenance (PdM) builds on statistical data collected from various sensors to build statistical models that can be identified before potential failures occur.

Введение решения

Predictive maintenance (PdM) builds on statistical data collected from various sensors to build statistical models that can be identified before potential failures occur. This approach can use a wide range of tools, often in the cloud, such as statistical analysis and machine learning, to track device health trends. Condition monitoring (CM) is monitoring various parameters, such as vibration or temperature, to identify potential failures. This can be used to highlight problems and allow preventive maintenance to be scheduled to avoid damage. Continuous condition monitoring technology is commonly used in equipment such as compressors, pumps and motors. Data collection is an important part of the monitoring process and helps ensure the smooth operation of factory floors in Industry 4.0.

STEVAL-BFA001V1B is a sensor and IO-Link-based predictive maintenance kit designed for condition monitoring (CM) and predictive maintenance (PdM). It monitors environmental, acoustic and vibration data. The hardware kit includes industrial sensors Board (STEVAL-IDP005V1) for ST-LINK / V2-1 programming and debugging, an industrial M12 cable for power supply or connection to the main port Use a standard multi-pole cable to manage the connection, one wire for IO-Link data, one for the L + line (positive supply voltage pole), and one for the L- line (negative supply voltage pole).

STEVAL-IDP005V1 is specially designed in size (50mm x 9mm x 9mm) to reflect real industrial applications and needs. The package includes dedicated algorithms for advanced time and frequency domain signal processing, as well as analysis of a 3D digital accelerometer with a flat bandwidth of 3 kHz. The software package includes drivers for pressure, relative humidity and temperature sensor monitoring. Audio algorithms for acoustic emission (AE) are also part of the package. The program runs on a high-performance STM32F469AI, ARM®Cortex®-M4, 32-bit microcontroller, and the sensor data analysis results are sent via a wired connection based on the IO-Link device transceiver. The STEVAL-BFA001V1B reference design is suitable for monitoring motors, pumps and Fans and accelerates the development of predictive maintenance solutions. The software package also allows connection to a multi-port evaluation board with STEVAL-IDP004V1 IO-Link master function; the PC GUI included in the package displays algorithm output and sensor data. By simply connecting STEVAL-IDP005V1 to a PC via the STEVAL-UKI001V1 adapter and ST-LINK / V2-1 on any STM32 Nucleo-64 development board, you can also use a public terminal emulator to display data on the PC. The program is available for free on STSW-BFA001V1.

Hardware design

Power management

1. L6984 is a step-down monolithic switching regulator capable of providing up to 400 mA DC. This output voltage is adjustable from 0.9V. The fixed 3.3 V VOUT eliminates the need for an external resistor divider. This "low power mode" (LCM) maximizes efficiency at light loads and controls output voltage ripple. This "low noise mode" (LNM) makes the switching frequency almost constant over the load current range. This PGOOD open-collector output can achieve output voltage sequencing during the power-up phase. This synchronous rectification is designed for high efficiency and high switching frequency under medium and heavy loads to make the application compact. Pulse-by-pulse current sensing on low-side power components enables effective constant-current protection.

2. LDK220 is a low dropout regulator that can provide a maximum output current of 200 mA. The input voltage range is 2.5 V to 13.2 V, with a typical dropout voltage of 100 mV. Ceramic capacitors stabilize it on the output. Extremely low voltage drop, low quiescent current and low noise make it suitable for industrial applications. Enabling logic control puts the LDK220 in shutdown mode, allowing current consumption to be less than 1μA. The device also includes short circuit constant current limit and thermal protection.


The STM32F469AI microcontroller is based on a high-performance ARM®Cortex®-M432-bit RISC core running at frequencies up to 180 MHz. The Cortex®-M4 core has floating point unit (FPU) single precision and supports all ARM® single precision data processing instructions and data types. It also implements a full set of DSP instructions and a memory protection unit (MPU) to enhance application security. The device integrates high-speed embedded memory (up to 2 MB, up to 384 Kb of Flash memory). SRAM), up to 4 KB of spare SRAM and various enhanced I / O and peripherals connected to it. Two APB buses, two AHB buses, and a 32-bit multi-AHB bus matrix. The device provides three 12-bit ADCs, two DACs, one low-power RTC, twelve general-purpose 16-bit timers, including two PWM timers for motor control, two general-purpose 32-bit timers, and A true random number generator (RNG). The microcontroller has the following standard and advanced communication interfaces:


• Up to three I2C.

• Six SPI, two I2S full duplex. To achieve audio-level accuracy, synchronization can be done via a dedicated internal audio PLL or via an external clock.

• Four USART plus four UARTs.

• A SAI serial audio interface. The STM32F469AI device operates over a -40 to + 105 ° C temperature range from a 1.7 to 3.6 V power supply.


1. ISM330DLC is a system-level package with a high-performance 3D digital accelerometer and a 3D digital gyroscope tailored for Industry 4.0 applications. ST's family of MEMS sensor modules takes full advantage of the micromechanical accelerometers and gyroscopes already in use. Various sensing elements are manufactured using a special micromachining process. The IC interface is developed using CMOS technology. Special circuits can be designed and trimmed to better match the characteristics of the sensing element. In the ISM330DLC, the accelerometer and gyroscope's sensing elements are mounted on the same silicon chip on the same sensor, thus ensuring excellent stability and robustness. The full-scale acceleration range of the ISM330DLC is ± 2 / ± 4 / ± 8 / ± 16 g, and the angular rate range is ± 125 / ± 250 / ± 500 / ± 1000 / ± 2000 dps. Provides high accuracy and stability mode with ultra-low power consumption (high performance, combined 0.75 mA), and also enables durable battery-powered applications in the industrial sector. The ISM330DLC includes a dedicated configurable signal processing path with low latency, low noise, and

Dedicated filtering for control loop stability. The data that can be obtained from this dedicated signal path is provided via an auxiliary SPI interface and can be configured for gyroscopes and accelerometers. High performance, high quality, small size, low power consumption, and high durability against machinery make the ISM330DLC the first choice for system designers who create and manufacture systems

Versatile and reliable product. The ISM330DLC is available in a plastic ground grid array (LGA) package. STSW-BFA001V1 firmware package includes application and demo firmware support

Accelerometer section.

2. HTS221 is an ultra-compact sensor for relative humidity and temperature. It includes an inductive element and a mixed-signal ASIC to provide measurement information through a digital serial interface. The sensing element consists of a polymer dielectric planar capacitor structure capable of detecting relative voltages and consists of humidity changes, and is manufactured using a dedicated ST process. The HTS221 is housed in a small top-hat ground grid array (HLGA) package and is guaranteed to operate under the following conditions: Temperature range is -40 ° C to + 120 ° C.

3. LPS22HB is an ultra-compact piezoresistive absolute pressure sensor, which can be used as a digital output barometer. The device includes a sensing element and an IC interface to communicate with it from the sensing element to the application via I2C or SPI. The sensing element that detects absolute pressure is made using a dedicated process developed by ST. The LPS22HB is available in a full-die-hole LGA package (HLGA). Guaranteed over temperature range from -40 ° C to + 85 ° C. There are holes in the package to allow external pressure to reach the sensing element.

4. MP34DT05-A is a built-in ultra-compact, low-power, omnidirectional digital MEMS microphone with a capacitive sensing element and an IC interface. The use of special silicon to make sensing elements capable of detecting sound waves is used exclusively in the micromachining process for producing audio sensors. The IC interface is manufactured using a CMOS process, and a dedicated circuit that can provide the following functions can be designed: Digital signals in PDM format are used externally. MP34DT05-A is a low distortion digital microphone with a signal-to-noise ratio of 64 dB and a sensitivity of -26 dBFS ± 3 dB. MP34DT05-A uses SMD compatible, EMI shielded top port, and is guaranteed to work in the extended temperature range of -40 ° C to + 85 ° C.

IO-LINK communication

The STEVAL-IDP005V1 board has an IO-Link connection on the M12 A-coded connector. IO-Link is the industry standard for hardware connectivity. The standard states:

• Number of wires required for bus installation

• Color is used to distinguish the power supply voltage of the IO-Link bus

• Connector pin assignments.

The standard also establishes two different methods of data communication:

1. Pure Serial Data Communication (SDCI) with detailed protocol structure for managing sensor parameters and sensor data.

2. Simple level shift from high to low, and vice versa, only indicates sensor status. The use of the IO-Link system has several advantages, such as:

• IO-Link device automatic detection and parameter setting: The operating parameters of the device are stored in the host during the setting process. When connected, the master device recognizes the device and enables auto-start. If a device such as a sensor fails, it can be replaced and the parameterized data stored in the master device is automatically downloaded to the replacement device.

• Device monitoring and diagnostics: IO-Link allows monitoring of device components and systems, as well as proactive management. IO-Link devices provide diagnostic capabilities that allow control systems to track data and trends, facilitate preventive and predictive maintenance, and improve machine uptime.

• Dynamic change: Quickly adjust parameters for installed equipment while the machine is running, reducing time consumption.

• Reduce component cost: By using the configuration function of IO-Link, you can configure the device to have different output functions.


L6362A is a IO-Link transceiver device supporting COM1 (4.8 kbaud), COM2 (38.4 kbaud) and COM3 (230.4 kbaud) modes in compliance with PHY2 (3-wire connection) support. The output stage can be configured as high-side, low-side or push-pull through a hardware connection, which can drive resistive, capacitive and inductive loads. The IC can use a serial data communication interface (SDCI) to connect the sensor node to the host based on the IO-Link protocol and standard I / O mode (SIO). 24 V industrial power is used to manage the communication bus voltage. L6362A's VCC, GND, OUTH, OUTL and I / Q pins are reverse polarity protected. The IC also features output short circuit protection, overvoltage and fast transient conditions (± 1 kV, 500Ω and 18μF coupling).

The software runs on the STM32F469AI microcontroller and includes drivers for sensor devices HTS221, LPS25HB, ISM330DLC (accelerometer only), MP34DT05-A and M95M01-DF. This software package integrates complete middleware with algorithms for accelerometer data signal processing, enabling monitoring of rotating equipment such as motors, pumps and fans in the time and frequency domain. Bandwidth function (up to ODR / 2 = 3.3kHz). The software package includes audio library middleware to perform acoustic emission analysis. You can monitor environmental, acoustic and vibration data through a terminal emulator. The software comes with different demos and applications to monitor sensor data and output algorithm results. One demonstration is based on warning and alarm conditions in the time domain and spectral band based on programmable thresholds. This software package has IO-Link functionality (excluding the IO-Link stack) and comes with a demo for communicating with the STEVAL-IDP004V1 IO-Link-master-capable multi-port evaluation board.

Main features

A set of firmware examples for building condition monitoring and predictive maintenance application middleware based on 3D digital accelerometers, environmental and acoustic MEMS sensors, including advanced time and frequency domain signal processing algorithms for vibration analysis. Programmable FFT size ( 512, 1024 or 2048 points), programmable FFT average and overlap, programmable window (flat top, Hanning, Hamming), speed RMS moving average, maximum acceleration peak, middleware with integrated microphone algorithm for: PDM Convert PCM sound pressure audio, FFT is a firmware package developed by STM32F469AI, which can be easily ported to different MCU series, monitor PC data with any free terminal emulator and STEVAL-IDP004V1 multi-port evaluation board with IO-Link-master function A sample demonstration firmware that communicates with a dedicated PC GUI.

Ключевые компоненты

No. номер части Производитель
1 L6362A ST
2 L6362ATR ST
5 HTS221 ST
6 STM32F469AIH6 ST