電氣專業(yè)-外文翻譯--電容式傳感器操作第一部分：基礎(chǔ)-電氣類-文庫(kù)吧
2025-04-16 20:30 本頁(yè)面
【正文】 change in the position of the other item will be measured as a change in the position of the target. A technique called guarding is used to prevent this from happening. To create a guard, the back and sides of the sensing area are surrounded by another conductor that is kept at the same voltage as the sensing area itself. When the voltage is applied to the sensing area, a separate circuit applies the exact same voltage to the guard. Because there is no difference in voltage between the sensing area and the guard, there is no electric field between them. Any other conductors beside or behind the probe form an electric field with the guard instead of with the sensing area. Only the unguarded front of the sensing area is allowed to form an electric field with the target. Definitions Sensitivity indicates how much the output voltage changes as a result of a change in the gap between the target and the probe. A mon sensitivity is 1 V/ mm. This means that for every mm of change in the gap, the output voltage will change 1 V. When the output voltage is plotted against the gap size, the slope of the line is the sensitivity. A system39。s sensitivity is set during calibration. When sensitivity deviates from the ideal value this is called sensitivity error, gain error, or scaling error. Since sensitivity is the slope of a line, sensitivity error is usually presented as a percentage of slope, a parison of the ideal slope with the actual slope. Offset error occurs when a constant value is added to the output voltage of the system. Capacitive gauging systems are usually zeroed during setup, eliminating any offset deviations from the original calibration. However, should the offset error change after the system is zeroed, error will be introduced into the measurement. Temperature change is the primary factor in offset error. Sensitivity can vary slightly between any two points of data. The accumulated effect of this variation is called linearity erro. The linearity specification is the measurement of how far the output varies from a straight line. To calculate the linearity error, calibration data are pared to the straight line that would best fit the points. This straight reference line is calculated from the calibration data using least squares fitting. The amount of error at the point on the calibration line furthest away from this ideal line is the linearity error. Linearity error is usually expressed in terms of percent of full scale (%/.). If the error at the worst point is mm and the full scale range of the calibration is 1 mm, the linearity error will be %. 畢業(yè)設(shè)計(jì)（論文）外文翻 譯 Note that linearity error does not account for errors in sensitivity. It is only a measure of the straightness of the line rather than the slope of the line. A system with gross sensitivity errors can still be very linear. Error band accou
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