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New Hall effect digital plating (coating) Test

(2 +) (6) U: A and after a war _ amplifier, its output voltage U3 a - (R {/ R3) (2 A f), tl! R4l Huang Zhan lTRaR2 ~ + + Ktlut where .... RsR2KKl,[link widoczny dla zalogowanych], (7) that the measured plating (coating thickness and the digital voltmeter is proportional to the input voltage if more get a ({Il/R2KJfK1I) A t the time. Then (9) becomes ?: T (9) digital voltmeter input voltage ['.'s value is the plating (coating) thickness. Second, the actual circuit design and component selection 1. use gallium arsenide or silicon-type Hall element. The two components of the temperature coefficient is relatively small. has good temperature characteristics. 2. Since the magnetic circuit L, L, Ls a remanence, will bring measurement error, so the circuit L, a small selection of high remanence magnetic material; circuit L ( magnetic hoof through the workpiece) knock reduce its length, this would reduce the measurement error. 3. current source, and the Hall element of the current source design. from ( Cool

know, three semi-digital voltmeter input voltage U3. c1 / 1 ・. so,[link widoczny dla zalogowanych], and must be stable. to design a high stability constant current {}; f, as shown in Figure 2, which is a load coil or Hall element Gong. 2 figure Field K of the open-loop amplifier voltage gain greatly. Ken its own high input impedance, so r. ≈ 0, f. ≈ O. 【R on at this load current li a UxfRt1n) ■ d where, U is the precision F1430 voltage reference output voltage, the sampling resistor is constant month. Because, with the U proportional to the load roar on the availability of a stable current, (, one, or, I). Constant current source by taking into account the changes of temperature and time. In the circuit to take the following measures: The F1403 precision reference voltage source. The precision reference standard. 4 hours under the conditions of instability of 0.002, the output voltage is typically 2.5V. May use RXT0 series sampling resistor precision wire wound resistor, this resistor has a good stability. Selection of high-gain, low drift, low noise operational amplifiers, such as F5027, F07, F7650, XFC78 and so on. Selection of high transconductance, the small current through the power tube as the regulator. Good stability of the potentiometer used WXIB-1-0.5-type multi-turn trimming potentiometer Yan. 4. Digital voltmeter used 7106A / D converter and liquid crystal display composed of three semi-digital voltmeter. Third, the instrument's measurement range and accuracy. Improve the accuracy of this instrument, the key is close to zero 々 core selection of high remanence magnetic material, and minimize the length of the magnetic circuit. Here are the instrument measuring range and error 0 ~ 2m: ± (0.6 + 0.1 of full scale reading) 0 ~ 201: ± (1 full scale reading +0.2) 0 ~ 200 ~ an: ± ( full-scale reading of 2.5 and 0.5) which makes me know, as the thickness increases, the plating (coating) layer at the magnetic flux leakage increases, the measurement accuracy. References Eli Yao Guang person digital coating thickness gauge. Application of Electronic Technique, 1992 12. [2] Lu Wenke, DC Low Current Clamp Meter Digital Design, Electrical Measurement & Instrumentation. 1988】】 period. [3] Lu Wenke. A practical high-precision constant current source, instrument technology. 1999 3. [4] Liu Debin and so on. Micron displacement sensor and its application on thermal expansion. Electrical Measurement and Instrumentation, 1987 1. Cylindrical intelligent detection system of the rich i (Qishuyan Railway Locomotive & Rolling Stock Technology Research Institute). Abstract This paper introduces the intelligent measuring instrument of cylindrical structure, working principles and methods of measurement. Thousands of well control equipment fixed on the data acquisition system are analyzed in detail. First, the instrument's structure and working principle of cylindrical Figure 1 Schematic diagram of measuring instrument. L0 installed in the workpiece 11 and the thimble 8 rotary table between the tailstock column 2 of 7 along the rail surface 6 moves up and down by hand wheel, and locking hand wheel 5. I rotary table driven by a servo motor, probe (DGC a 8ZG / A-type sensors) 9 clamping frame 3 in the test, the test frame 3, the guide surface along the column 4 by the screw drive up and down. Screw driven by a servo motor 1. A servo motor are mounted inside the base 1. Measurement, the probe contact with the workpiece, the workpiece began to turn, the sensor section contour of the first t continuous sampling,[link widoczny dla zalogowanych], the work piece stops rotating. Probe or down to a distance of BU,[link widoczny dla zalogowanych], and began to turn the workpiece, while the sensor section contour begin sampling 1. After all scheduled sections Shu, the computer processing of data measured in accordance with Minimum Zone Evaluation of cylindrical error mouth], the last ten by a father I crucian carp white patients Ji 'porphyrin coins,,, Xi}

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