基于STM32的數(shù)據(jù)采集系統(tǒng)英文文獻(xiàn)

Design of the Data Acquisition System Based on STM32 ABSTRACT Early detection of failures in machinery equipments is one of the most important concerns to industry In order to monitor effective of rotating machinery we development a micro controller uC OS II system of signal acquisition system based on STM32 in this paper we have given the whole design scheme of system and the multi channel vibration signal in axis X Y and Z of the rotary shaft can be acquired rapidly and display in real time Our system has the character of simple structure low power consumption miniaturization Keywords STM32 data acquisition embedded system uC OS II 1 1 Introduction The real time acquisition of vibration in rotating machinery can effectively predict assess and diagnose equipment operation state the industry gets vibration data acquisition Rapidly and analysis in real time can monitor the rotating machinery state and guarantee the safe running of the equipment In order to prevent failure reduce maintenance time improve the economic efficiency The purpose of fault diagnosis system can detect these devices through the vibration signal acquisition of rotating machinery and process the data acquisition then it will make timely judgment of running state of equipment While the data acquisition module is the core part of the fault diagnosis system 1 4 The practical application in the industrial field is the equipment operating parameters will be acquired to monitor equipment operating state In traditional data acquisition systems the data from acquisition card are generally send into the computer and specific software will be developed for the data acquisition The main contribution of this paper has designed the STM32 platform with ARM technology that has become a traditional mainstream technology in embedded systems and the collecting data toward the direction of high real time multi parameter high precision while data storage become large capacity more miniaturization and portable and the development of multicommunication mode and long distance for data transmission So as to meet the actual acquisition system multitasking requirements this article has designed based on STM32 micro controller uC OS II system of signal acquisition system Therefore in order to meet the actual acquisition system multitask requirements this novelty of this article has designed a signal acquisition system in micro controller uC OS II based on STM32 2 Architecture of data acquisition system Data acquisition as key technology for monitoring equipment recently a lot of work has been done on it An embedded parallel data acquisition system based on FPGA is Optimized designed which will make it reasonable to divide and allocate high speed and low speed A D 5 Instead it has use a high speed A D converter and Stratix II series of FPGA for data collection and processing in which the main contribution is used of the Compact Peripheral Component Interconnect the system has the characters of modularization sturdiness and scalability 6 But remote control will be needed in Special Conditions this paper introduce the embedded operating system platform based on Windows CE and uC OS II to design a remote acquisition and control system with the GPRS wireless technology 7 8 In order to achieve the data sharing of multi user it has build the embedded dynamic website for data acquisition management and dissemination with the ARM9 and Linux operation system 9 A data collection terminal devices is designed based on ARM7 microprocessor LPC2290 and embedded real time operating system uC OS II to solve the real time acquisition of multichannel small signal and multi channel transmission 10 On the other hands two parallel DSP based system dedicated to the data acquisition on rotating machines and the inner signal conditioner is used to adapt the sensor output to the input range of the acquisition and then signal post processing by the design software while the most frequently structure is to use DAS and FPGA based and such programs are also dependent on the DAS cost In order to meet market requirements of low power consumption low cost and mobility Fig 1 in this paper presents the design overall structure diagram of data acquisition system Through SPI interface the system gets the data collection with three axis acceleration sensor into the STM32 controller of inner A D conversion module with 12 bit this process is non interfering parallel acquisition Our system uses 240 x400 LCD and touch screen module real time to display the collected data in real time 2 1 STM32 micro controller A 32 bit RISC STM32F103VET6 used as the processor in our system compared with similar products the STM32F103VET6 work at 72MHZ with characters of strong performance and low power consumption real time and low cost The processor includes 512K FLASH 64K SRAM and it will communicate by using five serial ports which contain a CAN bus a USB2 0 SLAVE mode and a Ethernet interface what s more two RS232 ports are also included The system in our paper extend the SST25VF016B serial memory through the SPI bus interface that will regard as the temporary storage when collect large number of data furthermore we have the A D converter with 12 bits resolution and the fastest conversion up to 1us with 3 6 V full scale of the system In addition to design of the system power supply circuit the reset circuit RTC circuit and GPIO port to assurance system needs and normal operation 2 2 Data acquisition The machine state is normal or not is mainly depended on the vibration signal In this paper to acquire the vibration data of rotating machinery rotor we have used vibration acceleration transducers MMA7455L which could collect the data from axis x y and z of the company of Free scale The kind of vibration acceleration transducers has advantage of low cost and small size high sensitivity and large dynamic range with small interference MMA7455L is mainly consists of gravity sensing unit and signal conditioning circuit composition and this sensor will amplify the tiny data before signal preprocessing In data acquisition process of our system the error of sampling stage is mainly caused by quantified and the error is depended on the bits of the A D converter when we regard the maximum voltage as V max the AD converter bits is n and the quantization Q V max 2n then the quantization error is obeyed uniform distribution in q 2 q 2 13 The designed STM32 could built at most three 12 bit parallel ADC in this paper which theoretical index is 72dB and the actual dynamic range is between 54 to 60dB while 2 or 3 bits is impacted by noise the dynamic range of measurement can up to 1000 times with 60dB For the vast majority of the vibration signal the maximum sampling rate of 10kHZ can meet actual demand and the higher frequency of collection is generally used in the 8 12 bits AD therefore one of contribution of this work is to choose a built in 12 bit A D to meet the accuracy of vibration signal acquisition and lower cost in this experiment 3 Software design 3 1 Transplantation of C OS In order to ensure real time and safety data collection requirements in this system a kind of RTOS whose source code is open and small is proposed It also can be easily to be cut down repotted and solidified and its basic functions including task management and resource management storage management and system management The RTOS embedded system could support 64 tasks with at most 56 user tasks and four tasks of the highest and the lowest priorities will be retained in system The uC OS II assigns priorities of the tasks according to their importance the operation system executive the task from the priority sequence and each task have independent priority The operating system kernel is streamlined and multi tasking function is well compared with others it can be transplanted to processors that from 8 bit to 64 bit The transplant in the system are to modify the three file system structure OS CPU C H OS CPU C OS CPU A ASM Main transplantation procedure is as follows A OS CPU C H It has defined the data types the length and growth direction of stack in the processor Because different microprocessors have different word length so the uC OS II transplantation include a series of type definition to ensure its portability and the revised code as follows typedef unsigned char BOOLEAN typedef unsigned char INT8U typedef signed char INT8S typedef unsigned short INT16U typedef signed short INT16U typedef unsigned int INT32U typedef signed int INT32S typedef float FP32 typedef double FP64 typedef unsigned int OS STK typedef unsigned int OS CPU SR Cortex M3 processor defines the OS ENTER CRITICAL and OS EXIT CRITICAL as opening and closing interrupt and they must set to 32 bit of the stack OS STK and CPU register length In addition that has defined the stack pointer OS STK GROWTH stack growth direction from high address to lower address B OS CPU C To modify the function OSTaskStkInit according to the processor the nine remaining user interface functions and hook functions can be null without special requirements they will produce code for these functions only when the OS CPU HOOKS EN is set to 1 in the file of OS CFG H The stack initialization function OSTaskStkInit return to the new top of the stack pointer OS CPU A ASM Most of the transplant work are completed in these documents and modify the following functions OsStartHighRdy is used for running the most priority ready task it will be responsible for stack pointer SP from the highest priority task of TCB control block and restore the CPU then the task process created by the user start to control the process OSCtxSw is for task switching When the current task ready queue have a higher priority task the CPU will start OSCtxSw task switching to run the higher priority task and the current task stored in task stack OSIntCtxSw has the similar function with OSIntSw in order to ensure real time performance of the system it will run the higher priority task directly when the interrupt come and will not store the current task OSTickISR is use to handle the clock interrupt which needs interrupt to schedule its implementation when a higher priority task is waiting for the clock signal OS CPU SR Save and OS CPU SR Restore is completed to switch interrupt while entering and leaving the critical code both functions implement by the critical protection function OS ENTER CRITICAL and OS EXIT CRITICAL After the completion ofthe above work uC OS II can run on the processors 3 2 Software architecture Fig 2 shows the system software architecture so as to display the data visualized uC GUI3 90 and uC OS II is transplanted in the system our system contains six tasks such data acquisition data transmission LCD display touch screen driver key press management and uC GUI interface First of all we should set the task priority and the task scheduling based on the priority It needs complete the required driver design before the data acquisition such as A D driver touch panel driver and system initialization while the initializations include hardware platform initialization system clock initialization interrupt source configuration GPIO port configuration serial port initialization and parameter configuration and LCD initialization The process is that the channel module sent sampling command to the AD channel then to inform the receiver module it has been sent the sample start command the receiver module is ready to receive and large data will store in the storage module after the completion of the first sampling channel module will send the complete command of sampling to the receiver module the receiver sends an interrupt request to the storage module to stop the data storing then the data will display on the LCD touch screen The data acquisition process shown in Fig 3 4 Experiments The experiment of the embedded system has been done and data acquisition comes from the acceleration of MMA7455L which is installed on the bench of rotating machine The data acquisition have displayed as shown in Fig 4 and Fig 5 the system can select three channels to collect the vibration signal from the three directions of X Y and Z axis and in this paper the sampling frequency is 5KHZ and we have collect the vibration signal from normal state of unbalanced state at the same channel The result shows that our system can display real time data acquisition and predict the preliminary diagnosis rapidly 5 Conclusion This paper has designed an embedded signal acquisition system for real time according to the mechanical failure occurred with high frequency of in the rotating machines The system is based on a low cost microcontroller Vibration signals is picked by the three axis acceleration sensor which has the performance of low cost and high sensitivity and the acquisition data from axis x y and z We have designed the system hardware structure and analyses the working principle of data acquisition module The proposed system of uC OS II realize the data task management and scheduling and it is compacted with structure and low cost what s more the system collects the vibration signal and analysis in real time of the rotating machines and then quickly gives diagnostic results Acknowledgements This work was supported by The National Natural Science Foundation of China 51175169 China National Key Technology R Planned Science and Technology Project of Hunan Province 2009FJ4055 Scientific Research Fund of Hunan Provincial Education Department 10K023 REFERENCES 1 Cheng L Yu H Research on intelligent maintenance unit of rotary machine Computer Integrated Manufacturing Systems vol 10 Issue 10 page 1196 1198 2004 2 Yu C Zhong Ou Zhen D Wei F Design and Implementation of Monitoring and Management Platform in Embedded Fault Diagnosis System Computer Engineering vol 34 Issue 8 page 264 266 2008 3 Bi D Gui T Jun S Dynam Behavior of a High speed Hybrid Gas Bearing 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