Elec­tro­mag­netic com­pat­i­bil­ity test­ing in EMC lab

EN 61000 – 4–2:2009 Elec­tro­mag­netic com­pat­i­bil­ity (EMC)–Part 4–2: Test­ing and mea­sur­ing tech­niques– Elec­tro­sta­tic dis­charge immu­nity test (IEC 61000–4–2:2008)

Ana­log: IEC 61000 – 4-2:2008 Elec­tro­mag­netic com­pat­i­bil­ity (EMC)-Part 4 – 2: Test­ing and mea­sur­ing tech­niques– Elec­tro­sta­tic dis­charge immu­nity test.

Scope
Inter­na­tional stan­dard EN 61000 – 4-2:2009 defines sus­cep­ti­bil­ity require­ments regard­ing Elec­tro­sta­tic Dis­charge (ESD). This stan­dard defines test setups, envi­ron­ment and test lev­els for elec­tri­cal and elec­tronic equip­ment test­ing, that is sub­jected to ESD from user directly or indi­rectly.

This stan­dard should be used together with generic stan­dards or spe­cific prod­uct stan­dards as EN 61000 – 4-2:2009 does not pro­vide spe­cific infor­ma­tion on par­tic­u­lar equip­ment test­ing.

Gen­eral
Sta­tic charge is an unbal­anced elec­tri­cal charge at rest. Typ­i­cally, it is cre­ated by insu­la­tor sur­faces rub­bing together or pulling apart. One sur­face gains elec­trons, while the other sur­face loses elec­trons. This results in an unbal­anced elec­tri­cal con­di­tion known as sta­tic charge. When a sta­tic charge moves from one sur­face to another, it becomes ESD. ESD is a minia­ture light­ning bolt of charge that moves between two sur­faces that have dif­fer­ent poten­tials. It can occur only when the volt­age dif­fer­en­tial between the two sur­faces is suf­fi­ciently high to break down the dielec­tric strength of the medium sep­a­rat­ing the two sur­faces. When a sta­tic charge moves, it becomes a cur­rent that dam­ages or destroys gate oxide, met­al­liza­tion and junc­tions. ESD test is car­ried out in two ways:

  1. Con­tact dis­charge (pre­ferred method)- method of test­ing in which the elec­trode of the test gen­er­a­tor is kept in con­tact with the EUT or cou­pling plane and the dis­charge is actu­ated by the dis­charge switch within the generator;
  2. Air dis­charge– method of test­ing in which the charged elec­trode of the test gen­er­a­tor is moved towards the EUT until it touches the EUT;


Test level
Inter­na­tional stan­dard EN 61000 – 4-2:2009 pre­fer the fol­low­ing test lev­els and volt­age ranges. Detailed test level selec­tion is defined in generic stan­dards and spe­cific prod­uct standards.


Applied con­tact dis­charge ESD pulse wave­form is char­ac­terised using cur­rent. Cur­rent wave­form para­me­ters should fit require­ments defined in table.



Test setup
Floor is cov­ered with grounded metal­lic sheet– ground plane. Table (height 0.8m) is cov­ered with hor­i­zon­tal cou­pling plane– HCP. Hor­i­zon­tal cou­pling plane is con­nected to ground plane using two 470Ohm resis­tors. Ver­ti­cal cou­pling plane (VCP) (0.5m x 0.5m) is located on table. Ver­ti­cal cou­pling plane is con­nected to ground plane using two 470Ohm resis­tors. Device under test is placed on table on 1mm insu­la­tion sheet.


If device under test is floor stand­ing equip­ment, floor stand­ing test setup should be used. Device under test should be located on 10cm insu­la­tion sup­port above ground plane on floor. Ver­ti­cal cou­pling plane– VCP, should be con­nected to ground plane using two 470Ohm resistors.

Appli­ca­tion of direct ESD pulses
Con­tact dis­charge is applied to con­duc­tive sur­faces and points or sur­faces and points cov­ered by non­con­duc­tive layer, that is not used as insu­la­tion. Air dis­charge is applied to all other points and sur­faces.
ESD pulses are applied to those points which are acces­si­ble by per­sons under nor­mal use (unless stated oth­er­wise by generic or spe­cific prod­uct stan­dards). ESD pulses are not applied to:

  • points and sur­faces that are acces­si­ble dur­ing maintenance;
  • points and sur­faces acces­si­ble under service;
  • points and sur­faces that are not acces­si­ble after final installation;
  • con­nec­tor pins that are pro­tected by metal­lic shell;
  • con­nec­tor con­tacts and other acces­si­ble parts that are ESD sen­si­tive due to func­tional rea­sons and are pro­vided by ESD warn­ing label.


Appli­ca­tion of indi­rect ESD pulses
Indi­rect ESD pulses are applied to hor­i­zon­tal cou­pling plane and ver­ti­cal cou­pling plane. Con­tact dis­charge is used. Ver­ti­cal cou­pling plane is located in 10cm dis­tance from equip­ment under test.

Per­for­mance cri­te­rion
The tests results are clas­si­fied in terms of loss of func­tion or degra­da­tion of per­for­mance. Inter­na­tional stan­dard EN 61000 – 4-2:2009 does not define Pass/​Fail cri­te­ria. This is defined by generic or spe­cific prod­uct stan­dards. EN 61000 – 4-2:2009 defines per­for­mance cri­te­ria that can be used to eval­u­ate equip­ment under test per­for­mance.

Per­for­mance cri­te­rion A
Nor­mal per­for­mance within lim­its spec­i­fied by the man­u­fac­turer;

Per­for­mance cri­te­rion B
Tem­po­rary loss of func­tion or degra­da­tion of per­for­mance. Self-​recovery after the test, with­out oper­a­tor inter­ven­tion;

Per­for­mance cri­te­rion C
Tem­po­rary loss of func­tion or degra­da­tion of per­for­mance. Oper­a­tor inter­ven­tion needed for recov­ery after the test;

Per­for­mance cri­te­rion D
Loss of func­tion or degra­da­tion of per­for­mance which is not recov­er­able. Dam­age
of hard­ware or soft­ware, or loss of data.


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