Abstract: This article introduces a digital vibration test device based on the PC104 architecture. Using this device, real-time measurements can be performed on each component of a certain type of engine vibration tester, and the tester can be evaluated as a whole based on the measurement results, providing an adjustment report . Keywords : vibration; PC104; real-time measurement [b][align=center]Design of Test Instrument of Vibration Test device CHEN Peng, ZHU Gang[/align] [/ b] The original imported measuring device was an analog electronic measuring device, which was manually operated, cumbersome to use, had low accuracy, and was costly. This article introduces a digital portable vibration tester detection device with a PC104 computer as its core. This device is fully digitally designed, measures in real time, and can issue operation commands according to maintenance requirements, eliminating cumbersome operation steps, reducing the labor intensity of staff, and improving the detection accuracy of the tester. 2 Hardware Design 2.1 Introduction to Vibration Tester and Detection Device The vibration tester mainly consists of two vibration sensors and one signal amplification electronic component. The vibration sensor is based on the law of electromagnetic induction. When vibrating, a corresponding induced electromotive force is generated in the coil inside the sensor. The voltage signal output by the sensor is amplified, detected, and transformed by the electronic component, converting the signal into a signal that can be received by the aircraft and indicated by the indicator. 2.2 Hardware System Design Principle This detection device can perform off-site measurement of the sensors and electronic components according to maintenance requirements. The hardware system mainly consists of an AC power supply, a DC power supply, an electric vibration table, a PC104 computer system, an 8038 function generator, a signal acquisition and processing module, a communication module, and corresponding conditioning circuits. The hardware system design principle is shown in Figure 1. [align=center]Figure 1[/align] During vibration sensor testing, a standard mechanical vibration with adjustable frequency, amplitude, and acceleration is provided by an electric vibration table. The sensor senses the vibration and generates a corresponding electromotive force, which is then input into an A/D board for A/D conversion. The electronic component is the focus of the test. It is driven by a 115V±15% 400Hz±10% AC power supply. The computer program outputs a certain voltage through D/A conversion, controlling the 8038 function generator to output a frequency-adjustable sine wave signal. This vibration simulation signal is connected to the component via a measurement socket, and after conditioning and amplification, it outputs a corresponding voltage, which is also input into the A/D board for conversion. The collected data processed by the A/D board is input into the computer for analysis and comparison with standard data in the background database, finally generating a test report. In addition, the system also provides a communication module, allowing users to upload data to a PC for detailed analysis. 2.3 Main Technical Implementation The PC104 is an IEEE-P996 industrial control bus specifically defined for embedded control. Its signal definition is basically the same as that of PC/AT. It is an optimized, small, stacked embedded control system that provides complete external interfaces. This system uses a PC104 module based on a 486DX CPU, which can effectively perform the required real-time measurement tasks. It connects to peripheral devices through external interfaces to complete input, display, and data storage. The data acquisition and processing module uses the corresponding DMM-XT module, which integrates 16 channels of 12-bit A/D input and 2 channels of 12-bit D/A output, with a maximum sampling rate of 100kHz, enabling accurate measurement of operating voltage. The electric vibration table uses a certain company's ES-1 general-purpose vibration table, providing simulated vibration in the frequency range of 5-4500Hz. The communication module uses an RS232-RS485 conversion module to ensure good signal transmission performance. After the data is uploaded to the host computer via the RS485 serial bus, it can be independently analyzed using the accompanying software. 2.4 Design of Function Generator Circuit The function generator circuit is the core part of the circuit design. In this device, an 8038 is used to construct a frequency-adjustable function generator. The 8038 function generator is a large-scale integrated circuit capable of generating square waves, triangle waves, sawtooth waves, and sine waves. It can be controlled by a computer to generate a frequency-adjustable sine wave. The working principle diagram is shown in Figure 2. The sine wave used for measurement is obtained by converting a triangle wave through a sine wave converter and is output from pin 2. This signal is connected to the electronic component under test to provide a sinusoidal analog signal. By adjusting the 1kΩ and 10kΩ potentiometers, the distortion of the sine wave can be reduced to about 0.5%. The voltage between pins 6 and 8 is controlled by a D/A converter. By adjusting the input voltage between the two pins through a program, the function generator is controlled to provide a frequency-variable signal of 20–2000Hz according to maintenance requirements. [align=center]Figure 2[/align] 3 Software Design The system software is based on the DOS system, using Borland C++ 3.1 as the development platform. It employs a graphical interface and uses interrupt control for real-time data acquisition, storage, and performance evaluation. The software flowchart is shown in Figure 3: [align=center]Figure 3[/align] 3.1 The programming system for the initialization module is the DOS system. Therefore, corresponding graphics processing, Chinese character library calls, and extended memory call function libraries were designed. Graphical interface programming typically involves directly drawing on the screen, making the program obscure, verbose, and difficult to modify. To simplify operation, the program uses image calls, implementing the interface through calls to FLC files. FLC files can be drawn using appropriate graphics processing software, resulting in a beautiful and easily modifiable interface. 3.2 The real-time data acquisition module is mainly completed by rewriting the 1CH interrupt program. It automatically completes data acquisition, performance evaluation, and test data storage every 25ms until the system receives a stop test command. void interrupt(*oldint)(void) void interrupt newint(void) void main() {…… oldint=getvect(0x1c); setvect(0x1c,newint); } void interrupt newint(void)] { outportb(0x43,0x36); outportb(0x40,0x86); outportb(0x40,0x74); ……………(data processing) oldint(); } 3.3 Programming of the communication module An independent communication module is provided according to the equipment requirements. The communication program of the host computer is implemented by calling the MSCOMM32 control through Cbuilder5, which can run on Windows 95 and above operating systems; the communication program on PC104 completes the upload of test result data files by directly calling the bioscom() function built into BC31. 4 Conclusion Innovation points: Modularization, digitalization, and intelligence are the inevitable directions for the development of military maintenance and testing equipment. Based on this, this testing device was designed and developed. The device provides a user-friendly human-machine interface, simplifies operation, and can accurately and effectively complete the testing of a certain airborne vibration tester, achieving good results and meeting the predetermined design requirements. References: Zhang Xiaoming, Xu Huigang. Design of a multi-functional extended communication module based on PC/104 bus. Microcomputer Information, 2004, No. 5, pp. 43, 44, 59. Guo Weiqin. 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