subject: BIT technology and equipment control system fault diagnosis - laboratory equipment - Education Industry [print this page] BIT technology and equipment control system fault diagnosis - laboratory equipment - Education Industry
Introduction Built-in test (BIT) 70 years of the 20th century the United States made in the field of military test new Technology Concept, which aims to improve equipment maintenance, testing and self-diagnostic capabilities, but also to the mobility and security equipment system are greatly improved. Since the 70s of the 20th century to the field of aerospace and other defense industry is represented internally in Built-in test And self-diagnosis technologies, mainly in the technology to track and theoretical research stage. 90 years into the 20th century, rockets, satellites, aircraft and other aircraft test equipment developed essentially carried out around the VXI bus. Meanwhile, in some equipment within the system have appeared in the form of self expression functions Built-in test And the embryonic form of self-diagnosis [1]. BIT technology is proposed in this paper, a certain type of equipment control system, it can on the equipment control system for device Digital Can make use of computers and related equipment to collect device information interface job information, the various functional modules Real-time monitoring The timely detection of faults, the fault location to the site can replace the unit, quick guide for parts and maintenance service personnel.
Built-in test Key Technologies Realize in equipment control system Built-in test And self-diagnosis should include Built-in test Equipment development and self-diagnosis method and to achieve two major parts. Among Built-in test There are two aspects: First, the measured object in the installation of test equipment, resulting in less or no external test equipment cases, complete control system and equipment performance testing; the other hand, the measured object in the system design for the various components function self-test design so that all components have self-test function, system-wide tests, comprehensive self-test functions of various parts of the completion of testing and information collection; and since then include fault diagnosis, feature extraction, knowledge base establish and inference algorithms and so on. Specific implementation, the first Built-in test Equipment acquisition of information through communication interface to send the computer to the ground, while self-diagnostic algorithm was also implemented on the ground of the computer. After the maturity of the technology to be both, and then test equipment and diagnostic Software All equipment control system built in-house, which is BIT technology, BIT technology equipment control system eliminates the need for ground test equipment for all the measured signal cables lead through numerous tests to detect the red tape to the ground while making the ground test equipment becomes no longer a large, complex, and shortening the equipment preparation time before the test, the operator of the equipment to meet the requirements of rapid response. With the wide application of computer technology, digital is already Electronic Equipment development direction. Digitizing equipment, making use of computers and related equipment to collect device information interface job information possible. This is to simplify the test equipment and its relationship with the equipment connected at the same time to achieve Built-in test And create the conditions for self-diagnosis.
As equipment space constraints, Built-in test And self-diagnostic technology must be to achieve the miniaturization of devices, including small computer systems, multi-channel high-precision A / D and D / A converter miniaturization miniaturization and communications interfaces [2]. Meanwhile, in order to achieve full sense Built-in test And self-diagnostics, built-stimulation methods must be addressed and the interior design of key equipment, technology incentives; In addition, in order to solve the traditional Built-in test The fault is not complex and can not identify intermittent failures and other issues must be solved by the small capacity built Storage The key technology equipment design; order to complete the built-in self-diagnosis technology, failure to address key technical knowledge base established in [3]. Several key technology that is directly connected to the Built-in test And self-diagnostic system performance is good or bad. This article will focus on the hardware design and troubleshooting knowledge base design in detail.
BIT system
Built-in test And self-diagnostic system, including signal conditioning modules, data acquisition module, data storage module, Diagnosis , Since the excitation module and the communication cable output module of six parts (see Figure 1). Analog voltage signal conditioning circuit is responsible for collecting the complete differential signal amplification, filtering and limiting other conditioning work. Logical volume, frequency, time, volume and pulse volume collection of the signal conditioning circuit for limiting the completion of the signal conditioning and data buffering and other work. Optical isolation is mainly to bring the measured signals and isolated from the computer, so you can ensure that data collection will not be grounded readings of potential difference or the common-mode voltage. Data storage module is mainly used to store some Built-in test And self-diagnostic system, diagnostic information, including measurement of digital information, the device's analog information, switch information, frequency information, pulse information, signal detection and fault information of the crude information of the corresponding code information and other functions. Equipment module control system from the main MCU incentive system equipment, the signal from the excitation control system also allows the computer through the communication cable ground to face the equipment to achieve self-excitation control. RS232/485 interface module can be host computer and PC Machine communication. Self-test module is mainly to achieve system self-test function, the design is to ADuC812 The DA / AD channel forming loops, the extra DI / DO channels formed loop to-end analog and digital channels working ability in self-test. DS12C887 mainly to the system clock chip provides a standard time base, on the data stored in Flash to add time items, the information flow on the PCM data transmitted to provide time stamps. The system microprocessor module selected ADI's ADuC812 Microcontroller (8-channel high-performance 5ms conversion time, 12-bit A / D converter, two 12-bit DAC, 10.5kB of flash memory E2PROM, with three 16-bit counter / timer and 32 programmable I / O interface 8051/8052 microcontroller, 256 bytes of SRAM) [4].
