EMC integration and cabling for equipment

Goals

formation-objectifs-seointro EMC integration and cabling for equipment :

Take into account all key EMC parameters when wiring and commissioning an industrial machine

The aim of this training course is to:
- Understand the regulatory requirements for CE marking
- Learn how to identify EMC risks on the machine
- Be able to identify the main sources of interference
- Know how to recognise and understand the coupling mechanisms involved
- Master the appropriate protection methods and their industrial implementation
- Know how to adopt an approach to solving EMC problems

Program

Introduction

EMC of an industrial system

Examples of inter-system disturbances

Evolution of electronics

EMC characterisation of equipment

Envelope detection by a junction

Voltage noise margins for logic circuits

Representation of a sinusoidal signal

Spectral envelope of repetitive pulses

Spectral density of a pulse

Time/frequency reciprocity

EMC is a functional objective

Compatibility margin

Use of decibels

Electronics: reminders



EMC requirements

European EMC Directive - Essential requirements

Technical documentation

Technical manual

European EMC Directive - Harmonised standards

Example of EU declaration of conformity

CE marking



Emission standards

Classification of equipment according to CISPR

Narrowband disturbance

Broadband disturbance

Main detection modes

Measurement of conducted disturbances

Example of a Faraday cage

CISPR 11 / EN 55011: Radiated limits



Immunity standards

Main fundamental standards IEC 61000-4-X

IEC standard 61000-4-2

Schematic diagram of the D.E.S. generator and waveform

Example of test setup - equipment placed on the ground

Test IEC 61000-4-4 / NF EN 61000-4-4

EN 61000 - 4 - 4: Test implementation

IEC 61000 - 4 -5 test / NF EN 61000 - 4 - 5

IEC  61000-4-5  / Waveform

Test 61000 - 4 - 6 / NF EN  61000 - 4 - 6

NF EN  61000 - 4 - 6: test implementation

Dips, short interruptions and voltage variations

IEC  61000-4-3

61000-4-3: Test configuration

Radiated immunity in H field



Conducted disturbances

Common mode / Differential mode

Coupling through common impedance in a cable

Impedance of cylindrical conductors

Ground connections for equipment

Impedance of a

Impedance of a mesh

Equipotentiality of the ground

Capacitive coupling between board and ground

Differential mode crosstalk

Attenuation by twisting

Common mode crosstalk

Crosstalk reduction using a ground plane

Case study: sound system in a hall

Summary of conducted disturbances



Radiated disturbances

What is a field?

Coupling between E and H fields

Wave impedance according to distance

‘Magnetic field to loop’ coupling

Coupling between ‘electric field and cables’

Couplings in fields close to a ground plane

Summary of radiated disturbances



Sources of disturbances

Field radiated by a transmitter

Field propagation

Industrial HF equipment

Direct personal discharges

Destruction of an IC by handling

The lightning cloud

Negative lightning discharge

Typical values for a lightning strike

Protection levels according to standard NF EN 62305

Lightning levels by department

Ground potential rise

Radiation from an indirect lightning strike

Radiation from a transformer

Interference from digital electronics

Common mode of a hexaphasic thyristor bridge

Switching notches

The 5 types of switching disturbances

Variable speed drive

Overvoltage when relays are cut off

Diode in reverse parallel

Varistor in parallel

RC in parallel

Summary of the main sources of disturbances



Earthing

Neutral, PE and earth currents

Earth resistance measurement

Functions of an earth

Earth

Soil resistivity

Earth networks

« Earth » IT



Grounding networks

Grounding: Regulatory aspects

Definition and effects of ground loops

Definition and effects of loops between grounds

Ground loops in modern systems

Star grounding = common impedance!

Star wiring = large ground loop!

Ground conductor mesh

Example of an island: cabinet

Cabinet: details (1)

Cabinet: details (2)

Avoid separate earths!

Avoid isolated earths!

Example of an island: Technical room

Summary of grounding issues



Interconnection cables

Cabling with reducing effect

New best practices

BF common mode isolation components

Optocoupler envelope detection

MC rejection from a differential symmetrical connection

Where to connect the cable shielding?

Wiring of very low-level sensors

Examples of shielded cable implementation

Connection of shielded connectors

Use of shielded RJ11 or RJ45 connectors

Reducing effect of cable traysRJ11 or RJ45 shielded connectors

Reducing effect of cable trays

Different reducing effects

Shielding factor of cable trays

Use of cable trays

Connection of cable trays

Cable trays crossing walls

Signal classification

Shielding rules

Summary of cable problems



Surge arresters and filtering

Main surge arresters

Classification of LV surge arresters

Parameters of LV surge arresters

Surge protection

Installation of power/telecom surge arresters

Combined mains + telephone surge arresters

Different power filters

The 3 rules for installing mains filters

Common mode filtering on the chassis

Which ferrite to use?

Using ferrite sleeves

Summary of protection and filtering



Transmission lines

What is a transmission line?

Line parameters

Characteristic impedance

Propagation in a lossless line

Impulse lines: Reflection of a front

Signal shapes

When should a line be adapted?



Screens and shielding

How does shielding work?

Reflection losses

Absorption losses

Deflection of magnetic field lines

Shielding difficulties

Some conductive joints

Electrochemical couples

Penetration treatment

Internal cabling

Summary of screens and shielding



Validation

Mass continuity check

Choice of generator

Walkie-talkie tests

IEC 61000-4-4 / NF EN 61000-4-4 test

TER/S: On-site injection method

Rapid transients on site

Summary of validation issues



Remedial action

EMC failure: What should you do?

On-site EMC correction method

Specific instrumentation

Low-frequency current clamps

Use of HF clamp

Bius probebius

Use of a Mœbius probebius

Immunity: order of magnitude

Correction of common EMC errors

Summary of chapter



Conclusion

EMC of systems and installations: Acronyms

French EMC bibliography

Some interesting websites