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1、 Procedia Computer Science 17 ( 2013 ) 222 228 1877-0509 2013 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility of the organizers of the 2013 International Conference on Information Technology and Quantitative Management doi: 10.1016/j.procs.2013.05.030 Informati
2、on Technology and Quantitative Management (ITQM2013) Design of the Data Acquisition System Based on STM32 Hui-fu Zhang1, Wei Kang1* 1Department of Computer Science and Technology, Hunan University of Science and Technology, Xiangtan 411201, China Abstract Early detection of failures in machinery equ
3、ipments is one of the most important concerns to industry. In order to monitor effective of rotating machinery, we development a micro- 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,
4、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. 2013 The Authors. Published by Elsevier B.V. Selection and/or peer-review under responsibility of the organizers of the 2013 Interna
5、tional Conference on Computational Science Keywords: STM32; data acquisition; embedded system; -; 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
6、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 acqui
7、sition 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 paramete
8、rs 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 platfor
9、m 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 multi-
10、communication mode and long-distance for data transmission. So as to meet the actual acquisition system * Corresponding author. Tel.: 086-0731-15073230255. E-mail address: Available online at 2013 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility of the organizer
11、s of the 2013 International Conference on Information Technology and Quantitative Management 223 Hui-fu Zhang and Wei Kang / Procedia Computer Science 17 ( 2013 ) 222 228 multitasking requirements, this article has - system of signal acquisition system. Therefore, in order to meet the actual acquisi
12、tion system multitask requirements, this novelty of this article has designed a signal acquisition system in micro- 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
13、 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
14、 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 - to design a remote acquisition
15、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
16、ARM7 microprocessor LPC2290 and embedded real-time - to solve the real-time acquisition of multi- channel small signal and multi-channel transmission10.On the other hands, two parallel DSP-based system dedicated to the data acquisition on rotating machines, and the inner signal conditioner is used t
17、o 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 consumpti
18、on, 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
19、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. ? ? Reset circuit Power circuit RS232 USB Ethernet RTC circuit FLASH SRAM Lcd touch- screen JTAG MMA7455LA/D Fig.1 Hardware Framework of System 2.1. STM
20、32 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- 224 Hui-fu Zhang and Wei Kang / Procedia Computer Science 17 ( 2013 ) 222 228
21、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 throu
22、gh 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,
23、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 accelerat
24、ion 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
25、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
26、 regard the maximum voltage as maxV, the AD converter bits is n, and the quantization Q = Vmax/2n, then, the quantization error is obeyed uniform distribution in -q/ 2, q / 2 13. ( )0eep e de (1) 2 2 2 2 221 ()( ) 12 q n q q eep e deede q (2) 2 22 2 222 maxmaxmax 12()12 2 12 n SVVV x qNeq (3) ()610.
27、8 dB S n N (4) While eis average error, 2 n is error variance , and S N is SNR. 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 rang
28、e 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
29、12-bit A/D to meet the accuracy of vibration signal acquisition and lower cost in this experiment. 225 Hui-fu Zhang and Wei Kang / Procedia Computer Science 17 ( 2013 ) 222 228 2.3. Storage and display Real-time data acquisition is needed that we have designed the system with 64K * 12bit capacity on
30、 chip SRAM. The process is that the three-axis acceleration transducers system is connected to the controller with the SPI interface, it will start to collect data when acquisition request is received, then the data transmitted through the DMA and stored in the SRAM chip until the data buffer is ful
31、l, it sends a interrupt signal to CPU, and CPU read all the channels data from FIFO, then will display the result in the LCD directly. Our system is capable of rapid, real-time and efficient to collect the original data and visually displayed. 3. Software design 3.1. Transplantation of C/OS- In orde
32、r 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
33、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 - assigns priorities of the tasks according to their importance, the operation system executive the task from th
34、e 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:
35、 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 C/OS - II transplantation include a series of type definition to ensure its
36、 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 u
37、nsigned 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 st
38、ack 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
39、_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. 226 Hui-fu Zhang and Wei Kang / Procedia Computer Science 17 ( 2013 ) 222 228 OS_CPU_A.ASM Most of the transplant work are completed in these documents, a
40、nd 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
41、() 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 perfor
42、mance 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
43、_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 (). - can run on the processors. 3.2. Software architecture Fig.2 shows the system
44、 software architecture, so as to display the data visualized, and - is transplanted in the system, our system contains six tasks such data acquisition, data transmission, LCD display, touch screen driver, key-press interface. First of all, we should set the task priority and the task scheduling base
45、d 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 c
46、onfiguration, 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 larg
47、e 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 s
48、creen. The data acquisition process shown in Fig.3 227 Hui-fu Zhang and Wei Kang / Procedia Computer Science 17 ( 2013 ) 222 228 Task scheduling of C/OS-II Data acquisition Kiss-press management Lcd display C/GUI interface Touch screen drive Channel module Receiving module Storage module Data transm
49、ission USBUSAT Ethernet Create Sampling Task System Initialization AD Start Sampling Task Time Drive Initialization Start Sampling DMA Start LCD Display Sampling Completed Y Fig.2 Software Architecture of System Fig.3 Data Acquisition of Flow Chart 4. Experiments The experiment of the embedded system has been done and data acquisit