Study On Static Three-dimensional Weak Magnetic Detection System Based On LabVIEW

With rapid development of the electronics industry, various magnetic materials and magnetic devices are used more and more popular, which puts forward higher requirements for magnetic field measurements, especially for weak magnetic field measurement. Traditionally, most of magnetic field measurements are single-point and one-direction, that can not really and overall reflect characteristics of the measured magnetic field, and it is difficult to meet the test and measurement requirements. In response to these limitations, a detection system for static three-dimensional weak magnetic field has been constructed based on the virtual instrument technology LabVIEW for accurate measurement of weak static magnetic field in this study.In this study, based on the three-axis anisotropic magnetoresistance (AMR) sensor application development, a kind of magnetic field detection virtual instrument system, the core of which is computer, has been formed by controlling three-dimensional moving platform and three-dimensional magnetic field data acquisition with virtual instrument technique to realize the magnetic field distribution automatic acquisition and its graphical display. In addition, it also provides a friendly man-machine interface, to improve magnetic field detection accuracy and flexibility. Main research work of each chapter is outlined as following:In chapter II, from the basic characteristics and working principle of anisotropic magnetoresistive (AMR) sensor, it discusses the internal structure and technical specifications of three-axis AMR sensors, and proposes two plans to construct some common three-dimensional weak static magnetic field test system.First, it introduces its classification of magnetic sensors, compares them with other sensors, and analyzes some advantages of the AMR sensor.Next, the working principle and basic characteristics of AMR sensor are analyzed, and the internal structure and technical specifications of three-axis AMR sensor HMC1043 are mainly discussed on this basis, so as to lay a foundation for its further application.Then, the concept, feature and application fields of virtual instrument are illuminated and functional characteristics of LabVIEW virtual instrument dvelopment platform are also introduced here.Finally, it proposes two plans to construct some common three-dimensional weak static magnetic field test system, and analyzes their advantages and disadvantages by comparing the two plans.In chapter III, the design ideas and implement methods of each functional module in static three-dimensional weak magnetic detection system are mainly explained.First, it discusses the overall composition scheme of static three-dimensional weak magnetic field detection system, and makes the specify to the experimental scheme of the two main parts of system,that are the weak magnetic field detection system and the movement control system.Then, the design and implementation methods of each functional module in static three-dimensional weak magnetic detection system are introduced, focusing on core technical issues. The Vo-B characteristic relation of the magnetic field measurement module has been established by building its static characteristics testing system, on the base of the application circuit for HMC1043 magnetic sensor designed. The movement controlling module completes the automatic measurement of magnetic field for several points in space with movement of three-dimensional moving platform via DAQ acquisition card, thereby the efficiency of magnetic field measurement can be increased. In addition, the storage module provides a feasible method of data preservation for the magnetic field measurements, and the display module offer the way to displaying three-dimensional graph of magnetic field measurement, realizing perfect system functionality.In chapter IV, all functional modules are integrated into the static three-dimensional weak magnetic detection system from both hardware and software aspects to perfect the system functionally, and then the system is comprehensive verification tested testing taking the known regular distribution magnetic field as the test object. The results show that the static magnetic field detection system can accurately measure magnetic field intensity within a certain space (≤120mm×120mm).