1、附录 A Embedded Linux-based acquisition system With the rapid development of information technology, people need to accurate, fast and convenient access to large amounts of data and be able to quickly extract useful information. Embedded Systems is the IT network technology and a new direction of tech
2、nology development. American futurist Timor predicted during his visit to China in 1999: 4 5 years after the tool will be embedded PC and the Internet is the second greatest invention after. 20th century 90s, the application of embedded technology in full swing, has become the communications and con
3、sumer technology products, the main platform. In the field of automatic control, not only can be used in ATM machines, vending machines, industrial control and other special equipment and mobile communications equipment, GPS, a combination of entertainment, embedded systems play a huge role in the s
4、ame. The development of embedded technology makes it easy to develop embedded systems, reducing development costs, generic products increased to replacement. Combination of the traditional embedded systems are small, energy-less, anti-interference ability, stable characteristics, the development of
5、embedded data acquisition system products, whether as a stand-alone product, or a function of a system of modules, all It is very meaningful. Data Acquisition System is a computer, communications and electronic technology, industrial control for an integrated detection system. This paper introduces
6、embedded Linux-based data acquisition system hardware architecture and software design. To enhance the system to respond to the real-time performance and multi-task processing capability of hardware used in the ARM9 microprocessor technology, at the same time Linux operating system migration, system
7、 reliability and scalability can be improved. Designed to make full use of the characteristics of embedded Linux. System software modules have a data acquisition module, data processing module, data modules and data communications diagnostic module. Embedded Linux operating system will introduce a d
8、ata acquisition system design and accelerate the development of the system to facilitate the functions of the future expansion of the observational data to improve the timeliness and accuracy of observation to achieve the automation. Embedded system is application-centric, based on computer technolo
9、gy, software, hardware can be tailored to meet the application system functions, reliability, cost, size, power consumption, there are strict requirements of a dedicated computer systems, operating systems and features will integrated software systems in computer hardware, in a nutshell is the syste
10、m software and hardware integration, the work is similar to the way BIOS with software code in small, highly automated, fast response and so on. Particularly suited to the requirements of real-time and multi-tasking system. Embedded systems are advanced computer technology, semiconductor technology,
11、 electronic technology and the practical application of the various sectors of the product of the combination. Embed The structure of systems composed by two modules: the hardware platform and software platform. Acquisition Data Acquisition System at the scene to complete the task. Acquisition syste
12、m designed for distributed control systems, PC systems and on-site testing of the communication between digital serial based. Normal run-time, on-site detection of the controller to complete the next-bit data acquisition, data processing, data storage, data distribution and other tasks. System has a
13、 certain degree of self-detection, self-tuning capabilities, to unusual circumstances to the PC, in order to maintain. In order to adapt to a variety of different circumstances automatic detection of weld requirements, the entire detection system is modular design, different modules can be combined
14、into different applications. Micro-computers storage space smaller, while the standard Linux is a PC, and the need for the process of reducing the Linux kernel. For some added or removed independently of the function block can be retained only the kernel embedded system the functionality required to
15、 support the module, remove unwanted features. In order to meet certain real-time requirement and should not shield the kernel virtual memory management mechanism for enhanced real-time Linux. Computer systems are X86 motherboard architecture, compatible desktop PC version of Linuxi386. In this way,
16、 we can directly use the X86 system, the core of the compiler on Linux to compile the source code directly and cutting, and to avoid the core of the Linux source code part of involving CPU module and memory management module changes. Increase in file system and GUI based on system needs, the file sy
17、stem should include: the basic file system structure, the basic application, the basic configuration file, the basic equipment / dev / hd * and / dev / tty *, the basic procedures required to run the function library . GUI is a visual design software indispensable, but also for the future maintenanc
18、e of on-site visual inspection of the interface. Guide the preparation of Linux code, the system will start as diskonchip equipment, guidance on the code on diskonchip. Power system after the boot code from the basic hardware initialization, and then the kernel image into memory by the run. Embedded
19、 systems is usually a compact hardware platform, a dedicated and strong at the core of the processor, while a small number of peripherals combined with the application of relevance, the characteristics of diversity； embedded systems typically include embedded software applications and embedded opera
20、ting system. Embedded operating systems ranging from hardware and application procedures, is responsible for task scheduling and management of real-time applications, complete control of the hardware and operation. Real-time applications are based on real-time embedded operating system, the use of r
21、eal-time operating system mechanisms for the completion of the specific function of a specific embedded system applications. Embedded systems is different from the general computer system, it has other applications do not have a number of characteristics. Embedded Linux-based data acquisition system
22、 board design, mainly by a motherboard and a plug-9 motherboard. All the plug-3U structure, the module dual-socket connection between the module system motherboard linked to improve the reliability of the entire device. One plug-in boards for signal acquisition and processing； additional plug-ins fo
23、r the 8-channel signal conditioning board (a three-way on-board processing circuit, a total of 24 road, you can approach the basis of sensor signals, changes in signal conditioning channel plate). Compact system, the entire panel design, elegant appearance. System consists of signal conditioning sys
24、tems and signal acquisition, processing system constituted of two parts. Signal conditioning system from the charge to enlarge, zoom in or current-voltage amplifier circuit (depending on sensor type setting), program-controlled zoom, programmable low-pass filtering, amplification, such as a buffer c
25、ircuit composed of four levels, including single-chip control of PC by the request to enlarge the program, program-controlled parameters such as low-pass filter. Signal acquisition, processing system to be adopted ARM + FPGA structures. The benefits of such a structure are: the difficulty of the sma
26、ller hardware development platform, system software upgrades easy to implement. From field devices through a variety of sensor signals into low-noise cable channel signal conditioning board, each channel signal conditioning board that contains the three-channel signal conditioning. According to diff
27、erent types of sensors with different channel signal conditioning board, a variety of signals after signal conditioning for the same after the transformation of the voltage signal specifications. Signal processing flow is as follows: the sensor output signal voltage amplification, current amplificat
28、ion, such as zoom in or charge (as the sensor type setting) is transformed into voltage signal, the voltage signal amplification by the program, program-controlled low-pass filter, and finally to enlarge the buffer after processing, the output voltage signal to the signal acquisition, processing boa
29、rd. Embedded Linux system from the perspective of software generally can be divided into four levels. (1) boot loader. Including the curing of the firmware boot code (optional) and two major Bootloader. (2) core. Board-specific customization of embedded cores, as well as control of kernel boot param
30、eters. (3) file system. Including the root file system and the establishment of the Flash memory devices on the file system. It is a management system to provide a variety of configuration files and system implementation of user applications to run a good carrier of the environment. (4) user applica
31、tions and drivers. User-specific applications and drivers. Sometimes, the user applications, and between the inner nuclear layer may also include a built-in graphical user interface. System beginning in 2004 in the companys thermal power plant, BOF steel plant, power plants and other industrial application site. Practice shows that the embedded Linux-based data acquisition system to run stable and reliable.
