Rockwell-automation System Design for the Control of Electrical Noise Manuale Utente Scaricare il pdf (Pagina 56)

Publication GMC-RM001A-EN-P — July 2001

6-4 Contact Suppression

Figure 6.5

Transient absorber

Contact Suppression

Effects

The waveform below displays 7.2V peaks across the AC terminals of a

+24V dc power supply. Noise is due to load on the DC circuit being

switched.

Figure 6.6

Unsuppressed inductive load on the DC circuit

Good Solution

Better Solution

Common

+24V dc

Transient absorber

µs

-10123456789

-10V

-8

-6

-4

-2

10V

7.2V pk

Source Omron PSU AC Neutral

DC floating, Unsuppressed Relay

1 2 ... 51 52 53 54 55 56 57 58 59 60 61 ... 126 127

System Design for 1
Control of 1
Electrical Noise 1
Important User Information 2
Table of Contents 3
Table of Contents iii 5
Appendix A 6
Appendix B 6
Who Should Use this 7
Purpose of this Manual 7
Contents of this Manual 8
Related Documentation 9
Conventions Used in this 9
P-4 Preface 10
Chapter Objectives 11
What is Electrical Noise? 11
Understanding the Need for 11
Electrical Noise Control 11
Noise Control Basics 12
Figure 1.1 13
Figure 1.2 13
Coupling Mechanisms 14
Capacitance 15
Mutual Inductance 15
Solutions for Reducing 16
Implementation 17
Measuring Effectiveness 17
High Frequency (HF) Bonding 19
Noise Example 1 20
Noise Example 2 21
The Ground Plane Principle 21
Figure 2.3 22
Figure 2.4 23
Noise Solutions Using the 24
Ground Plane Principle 24
Painted Components 25
Anodized Aluminum Components 25
EMC Filters 25
Adjacent Panels 26
Grid and Raised Floor 27
Mezzanine Floor 28
Machine Structure 29
Panel ground plane 29
New Buildings 30
Existing Buildings 31
Grounding (Safety Earth) 32
Understanding the 33
Segregation Concept 33
Zone Classification 34
Component Categories 35
Routing Wires and Cables 36
Within a Panel 36
Figure 3.3 37
Routing very-dirty cables 37
Wire and Cable Categories 38
Data/Communications Cables 39
Routing System Wires and 40
Cables Between Panels 40
Shielding Concept 41
Ferrite Sleeves 42
Figure 4.3 43
Figure 4.4 43
Mixing Categories 44
Figure 4.5 45
Figure 4.6 45
Filtering Noise 47
IMPORTANT 48
Filter Performance 49
Performance Test Set-up 50
Test Results 50
Ultrasonic Transducers 51
Xenon Flashing Beacons 51
(strobe lights) 51
Earth Leakage/Ground Fault 52
Contact Suppression 53
Figure 6.1 54
RC suppressor circuit 54
Figure 6.2 54
Understanding Contact 55
Suppression for 24V dc 55
Circuits 55
Figure 6.7 57
Figure 6.8 57
Figure 6.9 58
Power Distribution 59
Figure 7.1 60
Filter test set-up 60
Figure 7.2 60
Transformers 61
Single Phase Power 62
24V dc Power Supplies 62
24V dc Distribution 63
24V dc PSU Zoning Methods 63
Figure 7.5 64
Figure 7.6 65
Filter between zones 65
Figure 7.7 66
Linear PSU 67
Figure 7.9 68
PSU mounted in Dirty Zone 68
Floating Requirement 69
Figure 7.11 70
Separate Clean Zones 70
Long Power Cable Runs 71
7-14 Power Distribution 72
Motor Wiring 73
Shielding Motor Power 74
Grounding Motor Power 74
Cable Shields 74
Applying Ferrite Sleeves 75
Splicing Motor Power 75
Handling Excess Cable 76
Installing Long Motor 76
Understanding Registration 77
Noise Reduction Methods 78
Figure 9.1 79
Figure 9.2 79
Registration power filter 79
Dedicated Power Supply 80
Detection Device Mounting 80
Signal Noise Filter Options 81
To Registration Inputs 83
From Detector 83
Registration Error 84
Error Compensation 85
Software Solutions 85
Encoders 87
Mounting 88
Power Supply Wiring 89
10-4 Encoders 90
E-Field Sniffing Method 93
H-Field Sniffing Method 94
Measuring AC Circuits 95
Figure 11.4 96
Ground Loops 97
Differential Measurements 97
Differential Scope Inputs 98
Scope Probe Lead Extension 99
General Guidelines for 100
Measuring Noise 100
Field Strength Meters 101
Monitoring for Noise 101
Monitoring Systems 102
Monitoring Panels 102
Noise Control Supplement 103
A-2 Noise Control Supplement 104
Noise Control Supplement A-3 105
A-4 Noise Control Supplement 106
Wire Segregation Test 107
A-6 Noise Control Supplement 108
Conclusions 109
Switch-Mode DC Power 110
Supplies 110
Grounding the Common 111
Figure A.8 112
Figure A.9 112
Grounded common 112
DC Filtering 113
AC Line Filters 114
Using a Dynamic Braking 115
Contactor 115
Figure A.13 116
Bonding Surfaces 117
Noise Checklist 118
EMC Product Suppliers 119
B-2 EMC Product Suppliers 120
I-2 Index 122
Index I-3 123
I-4 Index 124
Index I-5 125
I-6 Index 126

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