Fault diagnosis technology for circuit board of th

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With the rapid development of science and technology, especially the wide application of digital technology and all kinds of VLSI, the structure of electronic equipment, especially military electronic equipment, is becoming more and more complex, the function is becoming more and more perfect, and the degree of automation is also getting higher and higher. Although the performance of the electronic system has been improved, there are also many problems for testing and maintenance support, such as complex testing process, long testing time, difficult maintenance support, high maintenance cost, etc., which seriously affect the integrity and life cycle of electronic equipment

circuit board fault diagnosis technology can quickly and accurately judge whether the electronic system is abnormal, quickly locate the fault, and isolate the fault to the smallest replaceable unit. The application of modern fault diagnosis technology in the maintenance and guarantee of electronic equipment can improve the reliability and effectiveness of the system, ensure the maximum design capacity of the equipment, prolong the service life and reduce the life cycle cost; Through detection and monitoring, fault statistical analysis and performance evaluation, we can provide data and information for the optimization of equipment, which accounts for about 35% of the ternary system. Therefore, the research on electronic equipment, especially circuit board fault diagnosis technology, and the popularization and application of the research results have broad application prospects

overview and development prospect of fault diagnosis technology

fault diagnosis is based on the analysis and processing of the useful information obtained from the test of the diagnosed object, to judge whether the state of the diagnosed object is in an abnormal state or fault state, to determine the direction of the fault, and to predict the occurrence of the fault. Early fault diagnosis is to analyze the state characteristics of the diagnosed object, judge the existence of some faults, or predict the time of occurrence of faults, based on people's senses of the diagnosed object, such as feeling, hearing, touch and other senses, and the relevant experience accumulated in the past. Maintenance refers to all activities carried out to maintain or restore the equipment to the specified state, that is, it not only includes the repair of the equipment in case of failure (damage) in the process of use to restore its specified state, but also includes the preventive maintenance activities carried out to prevent the failure to maintain the specified state before the failure (damage). In recent years, digital technology and VLSI have been widely used in the design of functional circuit boards, and the function and structure of electronic equipment are becoming more and more complex. Therefore, its testing workload is large, and the quality of testing is high. Generally, it is difficult to rely on human senses and experience to detect the fault factors. Modern fault diagnosis technology is a new technology developed with the rapid development of electronic computer technology, modern testing technology and artificial intelligence technology in recent years. It refers to the application of modern instruments and computer systems and other high-tech equipment to check and identify the real-time technical status of equipment and parts through testing, and carry out scientific diagnosis. Using fault diagnosis technology to test and diagnose equipment can find equipment faults in time and prevent malignant accidents, so as to avoid heavy losses

Its experimental speed will also be relatively low

the United States is one of the countries that carried out systematic research on fault diagnosis technology. After the United States began to implement the Apollo program in 1961, a series of equipment failures occurred, prompting the United States mechanical fault prevention group (mfpg) chaired by the U.S. Naval Research Office (onr) under the initiative of NASA in 1967 to actively engage in the research and development of fault diagnosis technology. As the number one military power in the world, the United States attaches great importance to the logistics supply and maintenance support of military weapons and equipment. As the weapon system is becoming more and more complex, the equipment design is increasingly considering the support problem, so as to ensure that the maintenance work can be carried out simply and effectively, so that the equipment can always maintain the available state. Therefore, various types of fault diagnosis and maintenance expert systems have been used in U.S. F-15 fighter jets, B-1B bombers, naval ships Fault diagnosis and maintenance of military ordnance devices and other active weapons and equipment. At present, the United States occupies a leading position in diagnostic technology in aviation, aerospace, nuclear industry and military departments. Some European countries have also made great progress in equipment diagnostic technology. For example, the United Kingdom began the development and research of diagnostic technology in the late 1960s and early 1970s, and has some advantages in industry, nuclear power generation and so on

although the research on fault diagnosis technology started late in China, it has developed rapidly in recent years. In the development of important systems and equipment, clear testability requirements are put forward, and national military standards such as equipment testability outline (gjb-), testing and diagnostic terminology (gjb-) are formulated. Domestic military test systems are also gradually studied with the requirements of military equipment for test and diagnosis technology. At present, the domestic research on equipment fault diagnosis technology, especially the circuit board level fault diagnosis technology has made great progress

Beijing Aerospace Measurement and control technology development company has made great achievements in automatic testing, fault diagnosis technology research and related product development. It has developed "Huatuo electronic clinic" series products with independent intellectual property rights, including hteds8000 electronic equipment circuit board maintenance testing and diagnosis system, fault doctor fault diagnosis software platform and other products. This product comprehensively applies advanced testing and fault diagnosis technology, It is suitable for board level maintenance, testing and comprehensive support of electronic equipment, especially military weapons and electronic equipment, and has been popularized and applied in the Navy, air force, Second Artillery and other military arms

realization of circuit board fault diagnosis system

in order to realize circuit board testing and diagnosis, the fault diagnosis system should generally have system functions such as circuit board function detection, excitation signal generation, signal testing and acquisition, information management and data analysis. It can test and diagnose all types of circuit boards, and isolate and locate the fault to the smallest replaceable unit (such as components) where the fault occurs

the hteds8000 electronic equipment circuit board maintenance test and diagnosis system independently developed by Beijing Aerospace Measurement and control technology development company is based on VXI bus architecture, and has the structural characteristics of open, modular, comprehensive transformation of scientific and technological achievements of the college and Department of science and engineering of shandongnan University and easy expansion. The main task of the system is to achieve the actual working environment of the analog circuit board through the established system hardware platform, complete the diagnosis information acquisition of the tested board, the proportion of ncm111 and ncm622 is 13% and 10% respectively, and determine the fault location through the analysis and judgment of the diagnosis program, so as to complete the purpose of fault diagnosis. The main control computer software of the system realizes the control of VXI bus instrument and IEEE488 interface instrument through standard interface software, generates the excitation required for simulation test, loads it to the corresponding terminal of the edge connector of the tested board through general signal transfer box and special adapter, obtains the corresponding response data, and completes the fault location through the analysis and judgment of diagnostic software

hteds8000 electronic equipment circuit board maintenance test and diagnosis system architecture

electronic equipment circuit board maintenance test and diagnosis system is mainly composed of master computer, VXI bus instrument, IEEE488 interface instrument and special equipment. The hardware part has strong scalability, which can be increased or decreased according to the needs of users

vxi bus has the characteristics of compact structure, open standards, strong data throughput capacity, module reuse, etc., and the virtual instrument software structure (visa) solves the compatibility problems of the interface between computer and instrument and the application software development environment. GPIB bus, as a mature standard instrument bus, has a wide range of applications. The combination of the two bus interfaces in the system makes the system universal The expansibility of test function and measurement bandwidth and the ability of electromagnetic compatibility are further improved

for the test and diagnosis of various types of circuit boards, the system is connected to the circuit board under test through the special adapter of the circuit board under test, the excitation signal is sent to the special adapter through the general signal transfer box, loaded to the corresponding terminal of the circuit board under test, and the measured signal is sent to the signal measurement channel of the general signal transfer box. After conditioning and transfer, the measurement module in VXI measurement and control combination Function modules or GPIB measuring equipment realize signal measurement, control and acquisition. The main control computer coordinates and controls the work of the data acquisition and excitation equipment, and the test data is provided to the diagnostic expert system after corresponding preprocessing. Each circuit board can be tested and diagnosed by configuring a special adapter and a test and diagnosis program (TPS)

fault doctor fault diagnosis software platform

hteds8000 electronic equipment circuit board maintenance test and diagnosis system is equipped with the application software fault doctor Ver1.0 fault diagnosis software platform independently developed by the measurement and control company. According to the fault analysis theory, the software integrates advanced virtual instrument testing technology, artificial intelligence analysis methods, expert knowledge base, and can test various types of digital, analog and digital analog hybrid circuit boards Analysis and diagnosis

the software platform adopts advanced technologies such as OLE and com, builds a functional framework through COM interface, and then adds various functional modules in the framework according to needs, including various signal processing modules, test processing modules, instrument configuration operation modules, diagnostic algorithm processing modules, data information management modules, etc; The addition of each module is relatively independent, and data exchange is carried out through the main framework program; And new functional modules can be further improved or added. The software provides the interface of secondary development, adopts the software design idea of COM interface, solves the problem of programming and upgrading, and improves the reliability and scalability of the system

the software system includes test and diagnosis execution platform, test and diagnosis development platform, user interface platform, data information management platform, help and other functional modules. The test and diagnosis development platform completes the fault diagnosis and location of the tested circuit board, and provides automatic monitoring and information prompt functions; The test and diagnosis development platform provides a visual graphical interface environment to guide developers to input diagnosis steps, simulation incentives, data incentives, signal types, test power saving, instrument operation, etc., so as to complete the development task of test and diagnosis program; The user interface platform generates the display content of the diagnosis execution interface and completes the interactive setting of the human-computer interface; The data information management platform completes the functions of fault circuit board model statistics and original device statistical analysis, fault trend analysis and pre-test, and realizes the fusion of fault diagnosis and testing, information analysis and feedback

the software has the function of visual guidance. Developers do not need to master complex program coding, highly professional intelligent diagnosis algorithm and expert system principle. They only need to input expert knowledge and necessary test information through various process modules and corresponding functional components to establish a specific diagnosis software, which improves the efficiency of test and diagnosis development

circuit board fault diagnosis expert system and diagnosis methods

hteds8000 electronic equipment circuit board maintenance test and diagnosis expert system is divided into two parts: knowledge base and inference engine. For the diagnostic knowledge base, including the fault knowledge and normal knowledge of the circuit board, the knowledge of the knowledge base can be added, modified, deleted and optimized. The inference engine adopts a comprehensive intelligent inference engine based on the combination of general reasoning, neural network and fuzzy logic, which can not only improve the speed of diagnosis and reasoning, but also improve the accuracy of fault isolation. The construction of expert system is a gradually mature process. With the accumulation and optimization of diagnostic knowledge, fault diagnosis experts

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