电气专业-外文翻译--电容式传感器操作第一部分：基础-电气类(编辑修改稿)

电气专业-外文翻译--电容式传感器操作第一部分：基础-电气类(编辑修改稿)内容摘要：

nts for the bination of linearity and sensitivity errors. It is the measurement of the worstcase absolute error in the calibrated range. The error band is calculated by paring the output voltages at specific gaps to their expected value. The worstcase error from this parison is listed as the system39。 s error band. In Figure 7, the worstcase error occurs for a mm gap and the error band (in bold) is –. Gap (mm) Expected Value (VDC) Actual Value VDC) Error (mm) – – – – – – Figure 7. Error values Bandwidth is defined as the frequency at which the output falls to –3 dB, a frequency that is also called the cutoff frequency. A –3 dB drop in the signal level is an approximately 30% decrease. With a 15 kHz bandwidth, a change of 177。 1 V at low frequency will only produce a 177。 V change at 15 kHz. Widebandwidth sensors can sense highfrequency motion and provide fastresponding outputs to maximize the phase margin when used in servocontrol feedback systems。 however, lowerbandwidth sensors will have reduced output noise which means higher resolution. Some sensors provide selectable bandwidth to maximize either resolution or response time. Resolution is defined as the smallest reliable measurement that a system can make. The resolution of a measurement system must be better than the final accuracy the measurement requires. If you need to know a measurement within 181。 m, then the resolution of the measurement system must be better than 181。 m. The primary determining factor of resolution is electrical noise. Electrical noise appears in the output voltage causing small instantaneous errors in the output. Even when the probe/target gap is perfectly constant, the output voltage of the driver has some small but measurable amount of noise that would seem to indicate that the gap is changing. This noise is inherent in electronic ponents and can be minimized, but never eliminated. 毕业设计（论文）外文翻 译 If a driver has an output noise of V with a sensitivity of 10 V/1 mm, then it has an output noise of ,2 mm ( 181。 m). This means that at any instant in time, the output could have an error of 181。 m. The amount of noise in the output is directly related to bandwidth. Generally speaking, noise is distributed over a wide range of frequencies. If the higher frequencies are filtered before the output, the result is less noise and better resolution (Figures 8, 9). When examining resolution specifications, it is critical to know at what bandwidth the specifications apply. Capacitive Sensor Operation Part 2: System Optimization Part 2 of this twopart article focuses on how to optimize the performance of your capacitive sensor, and to understand how target material, shape, and size will affect the sensor39。 s response. Effects of Target Size The target size is a primary consideration when selecting a probe。