Abstract
Virtual Instrument (VI) was put forward as a novel instrument mode in the middle of the 1980s. It is a virtual-real measuring system based on PC computer and composed of sensors, modularized hardware interface cards and measurement software packages. It is a typical model for instrument design with intellectualizing, integrating, long-distance, and measurement & control as a whole. At present, VI for electrical measurement has been widely used. However, those for non-electric measurement are rarely reported, especially for geometrical measurement covering extensive fields and many sorts of sensors.To solve the problem, we reasearched virtual technology of geometrical measurement and developed an Inductive Micro-Displacement Instrument (IMDI) based on virtual technology.
First,the purpose and significance of the project are introduced in this dissertation, and the status of the art in virtual measurement at home and abroad is also described. Subsequently, the working principle of inductive sensor and the design of the signal process card of the IMDI are discussed. The dissertation also provides the detailed design schemes of pre-processing circuit and A/D sampling card based on ISA bus of the virtual IMDI.
The result shows that, in the range of 200m、150m、100m and 50m, the absolute linearities of the instrument are 0.62m、0.30m、0.28m and 0.16m respectively and the relative linearities are 1.6‰、0.9‰、1.5‰和1.6‰ respectively.The dispersion of the instrument is 0.16m and the standard deviation is 0.09m.The virtual system has achieved design requirement, it has large measurement range, high resolution, good precision, and is worth to extend.