基于LabVIEW的智能化磁性液体表观密度测试仪研制

Development of an Intelligent Instrument for Measuring the Apparent Density of Magnetic Fluids Based on LabVIEW

为满足磁性液体表观密度测试需要,研制了智能化磁性液体表观密度测试仪。根据单臂天平法的测试原理,利用可控升降台和程控电源实现磁场梯度变化,通过力敏传感器和AD转换器完成测锤力-电信号转换和处理,在单片机控制下将测试数据发送至上位机。设计基于LabVIEW的上位机操作程序,在"高度恒定改变磁场"和"磁场恒定改变高度"两种测试条件下,直接点击操作界面程控电源和步进电机各控制按钮,实现数据接收和处理、参数调节、结果显示和保存等功能。对自行制备的白油基磁性液体测试结果表明,表观密度随励磁电流增大而非线性增大;随测锤相对高度升高而非线性减小。全部测试操作过程简单方便,结果显示直观,提高了测量精度,满足在不同条件下磁性液体特性测试的需求。

An intelligent instrument for measuring the apparent density of magnetic fluids was developed in this paper to meet the needs of test. According to the principles of the single-arm balance, a controlled lifting and programmable power supply was used to change the magnetic field gradient, and mechanical signals of the plumb were converted to electrical ones by taking advantages of a force sensor and AD converter. All the data were transmitted to the host computer and properly handled under the control of a single-chip computer. Operation software was designed based on LabVIEW under different test conditions of adjusting the height with a constant magnetic field and adjusting the magnetic field with a constant height. By clicking the corresponding buttons of the programmable power and the stepping motor, it implements functions such as data reception and treatment, parameter adjustment, result display and save. The experiment result of the self-made white-oil-based magnetic fluid demonstrates that the apparent density of magnetic fluids increases nonlinearly with the increase of exciting current and decreases nonlinearly with the increase of relative height. It also shows that the operation of experiments is simple and convenient for measuring the apparent density of magnetic fluids. So it satisfies the needs of measuring the characteristics of magnetic fluids under different conditions.