Page 10 - Sensors and Control Systems in Manufacturing
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1.15.10 Calculating Center and Edge Contents ix
Points—Two Points . . . . . . . . . . . . . 38
1.15.11 Calculating Center, Middle, and
Edge Points—Three Points . . . . . . . 38
1.15.12 Calculating Four Calculation
Points . . . . . . . . . . . . . . . . . . . . . . . . . 39
1.15.13 Calculating Five Calculation
Points . . . . . . . . . . . . . . . . . . . . . . . . . 39
1.15.14 Calculating Eight Points . . . . . . . . . 39
1.16 LED and Spectralon . . . . . . . . . . . . . . . . . . . . 39
1.16.1 Spectralon® Material—Light
Reflectance Calibration . . . . . . . . . . 39
1.16.2 Spectralon ® Features . . . . . . . . . . . . 40
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2 Classification and Types of Sensors . . . . . . . . . . . . . 43
2.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2.1 Classification of Control Processes . . . . . . . . 48
2.2 Open- and Closed-Loop Control Systems . . . 50
2.3 Understanding Photoelectric Sensors . . . . . . 51
2.3.1 Principles of Operation . . . . . . . . . . 51
2.3.2 Manufacturing Applications of
Photodetectors . . . . . . . . . . . . . . . . . 52
2.4 Detection Methods . . . . . . . . . . . . . . . . . . . . . 58
2.4.1 The Through-Beam Detection
Method . . . . . . . . . . . . . . . . . . . . . . . . 58
2.4.2 The Reflex Detection Method . . . . . 58
2.4.3 The Proximity Detection Method . . . 59
2.5 Proximity Sensors . . . . . . . . . . . . . . . . . . . . . . 61
2.5.1 Typical Applications of Inductive
Proximity Sensors . . . . . . . . . . . . . . . 62
2.5.2 Typical Applications of Capacitive
Proximity Sensors . . . . . . . . . . . . . . . 64
2.6 Understanding Inductive Proximity
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
2.6.1 Principles of Operation . . . . . . . . . . 64
2.6.2 Inductive Proximity Sensing
Range . . . . . . . . . . . . . . . . . . . . . . . . . 67
2.6.3 Sensing Distance . . . . . . . . . . . . . . . . 68
2.6.4 Target Material and Size . . . . . . . . . 69
2.6.5 Target Shape . . . . . . . . . . . . . . . . . . . 71
2.6.6 Variation Between Devices . . . . . . . 72
2.6.7 Surrounding Conditions . . . . . . . . . 73
2.7 Understanding Capacitive Proximity
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
