EMC TEST – EN 61000-4-2 – ESD Electrostatic Discharge Immunity Test (Electrostatic Discharge Immunity Test)
The static electric charge in our bodies can reach 10-15 kV, and when static charge reaches a certain value and approaches a conductor, sudden discharges occur. The ESD test, one of the EMC tests, is an applied test method that detects in advance the interaction that static discharge can cause during human contact. A person with a static charge of 15 kV holding a sharp conductor can cause a current of up to 30 A to flow in a few nanoseconds. The ESD test conducted in EMC laboratories is performed in accordance with the EN 61000-4-2 harmonized standard under the 2014/30/EC Electromagnetic Compatibility Directive. This standard is used to verify the product’s immunity. ESD immunity tests can be performed directly or indirectly in two ways. In both cases, ESD is applied through contact (Contact Discharge) and air (Air Discharge).
The voltage values applied to the products in the electrostatic discharge test are specified in the table.
Test level 3 (6kV and 8kV) has been determined for light and heavy industrial equipment to simulate real threats, while test level 4 (8kV and 15kV) has been determined for medical equipment.
Air Discharge
When tested with this nozzle, the ESD gun is triggered by bringing it close to the product. The discharge is applied from the nozzle, the high voltage is suddenly discharged, and this can cause effects on the test samples.
Contact Discharge
When tested with this tip, the impacts specified in the table are now transmitted to the product directly through contact during the test. During the test, some surfaces, namely painted and oxidized surfaces, are not affected by the applied impacts. Therefore, these areas must be cleaned of any surfaces that could affect the discharge.
Tests are performed on the grounding plate. Since the device has a significant leakage capacity compared to the ground, it is placed 0.8 m above the ground and 10 cm above the ground test soil during the bench test. The ground plate must be 0.5 m wider than the device in all directions. ESD is applied perpendicular to the surface at these points as specified in the EN 61000-4-2 standard. ESD pulses are applied intermittently to the test points at least 10 to 15 times for each polarity. The values of the impulse and static discharge to be applied are determined based on the product’s intended use, in accordance with the values specified in Table 1 of the EN 61000-4-2 standard under Section 5. Test Levels. The product is classified according to its intended use. This classification is, in a way, the result of the EMC test. The evaluation of immunity tests conducted in accordance with Electromagnetic Compatibility Testing and Measurement is dependent on performance criteria. Performance criteria consist of four stages. The operating mode of the product must be specified before performance evaluation. During EMC testing, observations are made to determine if any changes occur. Based on the results of these observations, criteria are established, and the test result is determined.
