SNLA466A August   2024  – October 2024 DP83822I , DP83826E , DP83826I , DP83867E , DP83867IR , DP83869HM

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Abbreviation
  5. 2Introduction
  6. 3EMC Emission
    1. 3.1 Radiated Emission
      1. 3.1.1 Test Setup for Radiated Emission Test
      2. 3.1.2 Main Radiated Emission Sources
    2. 3.2 Conducted Emission
      1. 3.2.1 Test Setup for Conducted Emission Test
      2. 3.2.2 Main Conducted Emission Sources
    3. 3.3 Debug Procedure on EMC Emission
      1. 3.3.1 General Debug Procedure
      2. 3.3.2 RE Specific Debug
      3. 3.3.3 CE Specific Debug
  7. 4EMC Immunity Test
    1. 4.1 EMI Passing Criteria
    2. 4.2 Common EMI Knowledge
    3. 4.3 IEC61000 4-2 ESD
      1. 4.3.1 ESD Test Setup
      2. 4.3.2 Possible Root Cause of Failure
      3. 4.3.3 Debug Procedure
        1. 4.3.3.1 Follow the Test Setup
        2. 4.3.3.2 Remove External Factors on Cable or Link Partner
        3. 4.3.3.3 Areas to Explore to Improve ESD Performance
          1. 4.3.3.3.1 Air or Capacitive Coupling Discharge ESD Recommendations
          2. 4.3.3.3.2 Direct Contact Discharge ESD Recommendation
        4. 4.3.3.4 Schematic and Layout Recommendations
    4. 4.4 IEC 61000 4-3 RI
      1. 4.4.1 RI Test Setup
      2. 4.4.2 Possible Root Cause of Failure
      3. 4.4.3 Debug Procedure
        1. 4.4.3.1 Follow RI Test Setup
        2. 4.4.3.2 Remove External Factor on Cable or Link Partner
        3. 4.4.3.3 Found out Main Emission Area
        4. 4.4.3.4 Schematic and Layout Recommendation
    5. 4.5 IEC 61000 4-4 EFT
      1. 4.5.1 EFT Test Setup
      2. 4.5.2 Possible Root Cause of Failure
      3. 4.5.3 Debug Procedure
        1. 4.5.3.1 Follow EFT Test Setup
        2. 4.5.3.2 Remove External Factor on Cable or Link Parnter
        3. 4.5.3.3 Areas to Explore to Improve EFT Performance
        4. 4.5.3.4 Schematic and Layout Recommendation
    6. 4.6 IEC 61000 4-5 Surge
      1. 4.6.1 Surge Test Setup
      2. 4.6.2 Possible Root Cause of Failure
      3. 4.6.3 Debug Procedure
        1. 4.6.3.1 Follow Surge Test Setup
        2. 4.6.3.2 Remove External Factor on Cable or Link Partner
        3. 4.6.3.3 Area to Explore to Improve Surge Performance
        4. 4.6.3.4 Schematic and Layout Recommendation
    7. 4.7 IEC 61000 4-6 CI
      1. 4.7.1 CI Test Setup
      2. 4.7.2 Possible Root Cause of Failure
      3. 4.7.3 Debug Procedure
        1. 4.7.3.1 Follow CI Test Setup
        2. 4.7.3.2 Remove External Factors on Cable or Link Partner
        3. 4.7.3.3 Areas to Explore to Improve CI Performance
        4. 4.7.3.4 Schematic and Layout Recommendation
  8. 5Schematic and Layout Recommendation for All EMC, EMI Tests
    1. 5.1 Schematic Recommendation
    2. 5.2 Layout Recommendation
  9. 6Summary
  10. 7References
  11. 8Revision History

2 Introduction

As industrial applications require new topologies to meet faster cycle times, higher throughput, wider bandwidth, and smaller system architectures, real time Ethernet protocols such as Ethernet/IP, EtherCAT, Profinet, and so on are introduced to minimize latency. However, the protocols mentioned above all contain daisy chain architectures in real time systems. Therefore, a higher tolerance and immunity to external noise injected into the system is required to prevent information loss in the system. As another example, if any information is distorted, or link is broken in the early stage of the daisy chain network, all the remaining stages in the daisy chain network are also impacted. For example, if servo motors are connected to each stage of a daisy chain network, any signal loss in an early stage can prevent the remaining servo motors from functioning until commands are received from the earlier network stage. As a result, EMC in industrial applications has become a critical performance criterion for Ethernet.

Daisy Chain Topology Figure 2-1 Daisy Chain Topology

Electromagnetic compatibility (EMC) is defined into two main categories: Emission and Immunity

  • EMC Emission test is defined when the device or system functions properly without introducing unwanted or intolerable disturbance to the electromagnetic environment
  • EMC Immunity test or Electromagnetic Interference (EMI) is defined as the degradation in performance of devices due to unwanted disturbances created by the electromagnetic environment

In real time applications, there is always noise coupling to and from surrounding systems. This noise coupling is typically separated into four categories:

  • Conductive or Common impedance coupling
  • Inductive or Magnetic coupling
  • Capacitive or Electric coupling
  • Radiative coupling
Noise Coupling Path Figure 2-2 Noise Coupling Path

Understanding these noise coupling paths in the system or in the test setup are key to debugging EMC issues. This article provides an overview to each EMC/EMI test, debug procedures if theses fail, and schematic/layout recommendations to improve remove performance.