Embedded Software Design Of AC Field Detection Instrument Based On ARM

The alternating current field measurement (ACFM),an emerging non-destructivetesting technology, is developed based on an eddy current testing and magnetic fluxleakage detection. Its principle is when a uniform alternating is induced in thespecimen current by the AC electric field, due to the presence of a defect of the subjectspecimen, the induced current distribution becomes uneven, thereby causing thesurface of the test piece magnetic disturbances, the information of the defect can beobtained by analysed of the magnetic field perturbation detected. ACFM detectiontechnology has advantages without contact, without calibration, qualitative andquantitative analysis of the advantages of the defect, and the detection speed, lessdemanding on the specimen surface cleanliness, low cost, simple operation, and can bewidely used in aerospace, electric power, railway, petroleum, pipeline and pressurevessel industry. The instruments of the study on ACFM in our country is mainly thevirtual instrument software PC detection of analog circuit with LabVIEW, has obviousdefects.However, a large number of the use of analog circuitry, unable to avoid thedrawbacks of analog circuits, is bound to greater restrictions on the detection accuracy,the use of virtual instrument is too dependent on the PC, limiting the flexibility of thedetection.In this paper, based on the overall national natural science fund project requirements,based on a study of AC detection on the basic theory, the embedded field detectionsystem design scheme based on S3C2440and MSP430single chip processor as thecore. Doing this project using the Linux-2.6.30kernel, the design and implementationof Linux Bootloader bootloader, Linux kernel and root file system, and completed thedebugging of embedded system software platform based on Linux;according to therequirements of the program design, completed design and transplantation ofperipherals the driver of the LCD screen, touch screen, storage devices FLASH, serial,USB; The application of the the embedded AC field detection system software wasdesigned， selected embedded Qt graphical development framework, adoptedobject-oriented programming techniques. The software implements the the S3C2440and lower machine data communication wireless and wired two ways, adapt todifferent testing environment. Real-time data curve is displayed, according to the depthand length of the defect data quantitative calculation, setting circuit excitation source,the relevant parameters of the filter and amplification to adjust the performance of thecircuit, allowing the system to obtain the optimal data signal. Enter the keypad is verypractical module in the system without an external keyboard, the instrument is moreconvenient to carry. Last obtained by the standard test specimen test defect location,depth and length values, default values are basically the same, to verify the accuracy ofinstruments. The AC field detection system to meet project requirements, applicationsoftware can also be modified for other detection techniques, better versatility.