การเทียบวัดสเกลความยาวความละเอียดสูงด้วยตัวรับรู้แสงไฟฟ้า

High Resolution Measurement of Length Scales by Photoelectric Sensor

Name: สุรินทร์ อรรถกิจการค้า

Organization : มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

keyword: Signal to Noise Ratio

; Period Time

; Sensitivity

; Resolution

; Lower Limit Reading

; Calibration

; Uncertainty

; Confidence Level

; Tolerance

Abstract: This work is to study the characteristics of high resolution measurement of length scales by photoelectric sensor and to apply the instrument to measure a 1000 mm metallic ruler by detecting scale lengths to count values. The characteristics of the instrument are such as the signal to noise ratio of the sensor, the clock rate of the counting circuit, the speed of the driving motor, the sensitivity or the velocity of the sensor measurement, the resolution of the length measurement. This instrument consists of the photoelectric sensor [1] that generates the red color light of 0.1 mm diameter, with high efficiency to discriminate the color tone of black and white [2], and detects scale lengths to voltage signals while moving by a constant velocity along the ruler length. By comparing the reflected beam intensity to a reference intensity set on the sensor amplifier, the reflected beams from the black lines and the white metallic surface of the scale are converted to a train of low, L, and high, H, voltage signal alternately. These signals are counted by the Peripheral Integrating Circuit, PIC [3], operated at a constant clock rate. The count value of each signal is different and depends on the length of scales and sent to a computer by the RS232 serial port. The Microsoft Visual Basic program [4] calculates count values of each length intervals and converts to length values. The experimental result clearly indicates our instrument characteristic that has a signal to noise ratio of more than 10 dB, a resolution of 0.1 ?m / count, a resolution coefficient of the instrument to the ruler of 1 / 10000, the lower limit reading of 13 ?m. the clock period time of 0.136 sec ? 0.01 percent, the motor speed of 53849.7 count / cycle ? 0.03 percent, the sensor sensitivity of 9.4442 ? 10-5 mm / count ? 0.03 percent. And uncertainty of measurements is ? 0.03 mm for every 100 mm interval and ? 0.09 mm at the cumulative length of 1000 mm with the confidence level of approximately 95 percent.

มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี

Address: กรุงเทพมหานคร (Bangkok)

Email: info.lib@mail.kmutt.ac.th

Name: รศ.ดร. เอก ไชยสวัสดิ์

Role: อาจารย์ที่ปรึกษา

Created: 2546

Issued: 2005-09-19

Modified: 2006-05-10

วิทยานิพนธ์/Thesis

ISBN: 9744565101

CallNumber: INC124

tha

DegreeName: Master of Engineering

Level: Master's Degree

Descipline: Industrial Metrology

Grantor: King Mongkut's University of Technology Thonburi

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3	INC124ab.txt	2.42 KB

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