Why does my company need EMC services? EMC or electromagnetic compatibility is a test required by the different governments around the world on products with electronic circuitry. It is performed to determine and regulate the product’s radiated and conducted emissions. The aim of the test is to ensure that the emissions are within the acceptable range or spectrum of compatibility so as not to adversely affect the performance of similar products and at the same time for the product not to be affected by the emissions from similar products.
The test standards leading to certification are labeled differently according to product type and product origin:
• RCM mark (C-Tick) for Australia and New Zealand
• CE mark for Europe
• FCC for North America
• ISED (IC) for Canada
What are the EMC Tests required
The tests are conducted in authorized laboratories dedicated for the purpose. Compliance testing is made up of two parts – the emission test and the immunity or susceptibility test. Different standards based on locations may require only one part (say, immunity only) or both parts. More recently, a pre-compliance test was introduced to help manufacturers in facilitating the process of certification by having a pre-test in their plant where the products are in the final stages of manufacture.
Types of common EMC Emissions Testing
Essentially, the tests are centered on measuring the electromagnetic emission levels of the product, aiming to adapt the emissions to fall within the approved spectrum. In this way, the product becomes compatible with other products. There are various techniques being employed to measure this radiation level and radiation type. Some of these types are:
Radiated emissions and radiated disturbances
These are measured electromagnetic energy generated through fields that propagate radio frequencies around an enclosure. The fields are recorded in volts per meter or A/m or dBuA.
Conducted emissions and conducted disturbances
The tests check if such emissions coming from the electromagnetic field generated by the product may cause interference in a network.
AC mains port harmonics and flicker
These measure the harmonic current of the main supply this testing is usually mandated for AC mains products in Europe, commonly referred to as simply “Harmonics’. AC voltage changes, voltage fluctuations and flicker testing is a test to ensure that the main power supply does not fluctuate too much while a machine is operating through various cycles or modes of operation. This testing is usually mandated for AC mains products in Europe, commonly referred to as simply “Flicker’.
Types of common EMC Immunity and susceptibility testing
This is one of the most common simulation tests for the suitability of an electronic device to operate within a specified acceptable tolerance of performance when subjected to various types of simulated real world phenomena. These may be continuous phenomena or transient phenomena.
Radiated and conducted immunity and susceptibility tests
Considered as a continuous phenomena application of the interfering test signal. These EMC immunity tests are performed by injecting test signals onto products ports, cables or enclosure and observing the effect of on the product with respect to it’s normal behavior of a product.
Considered as a transient phenomena application of the interfering test signals. These EMC immunity tests are performed by injecting test signals such as electrical fast transients (EFT) and Electrostatic Discharges (ESD) and surges. These transient phenomena are applied to the either the products cable ports and the products enclosure directly or indirectly. Observation during testing is performed but usually the criteria of complying with the minimum acceptable performance is based on the ability of the product to recover after the completion of testing without user interventions.
AC mains voltage dips and interrupts
This is a test simulation of the mains electricity supply during black out and brown out and the effect it produces in the correct behavior of the product.