EMC compliance

In addition to the CE marking affixed to a product, customers may demand a European third-party (notified body) approval mark, certification, or test report connoting a higher level of quality to ensure safety/EMC compliance. To control non-conforming products the following clause from the Official Journal of the European Communities (OJEC) applies ... 

There are several ways for product and machine manufacturers to show compliance with the European directives. However, only one way presumes conformity— the use of harmonized European standards. This is why I strongly recommend the application of harmonized standards, also known as European Norms (ENs). Standards play an important role in European Union safety/EMC compliance for products and machines. Standards become valid in Europe after they are published in the Official Journal and are transposed into member states national standards. The ENs are listed or appended to the directives themselves. 

For most products and machines, the self-declaration process (module A) is possible. In practice the manufacturer performs the complete product assessment according to EU standards, issues the declaration, and affixes the CE marking to the product. A technical file or documentation must also be available on demand for national enforcement authorities. Keep in mind that this is an internal self-assessment process, a do-it-yourself approach, that results in issuance of the manufacturer s declaration of conformity and the CE marking (Figure 2-6). The buyer may demand proof of safety/EMC compliance in the form of a mark, certificate, or test report from a European notified or competent body. 

Certificates and approval-marks. Visible attestations from European accredited testing and certification bodies that provide positive evidence of conformity. Approval marks are product quality marks for safety/EMC compliance. Certificates and marks are supported by verifiable and accurate test reports from EU-notified or competent bodies. Marks and certificates establish the independent verification of a product s conformity that customers may demand. Regular follow-up inspections are performed, on equipment with EU approval marks, by the certification body to ensure ongoing conformity. When issued by recognized European certification bodies, official certificates and test reports provide the ultimate defense of due diligence should a product s conformity come into question. 

Montrose, M.1.1995. Printed Circuit Board Design Techniques for EMC Compliance. IEEE Press, New York. 

Test Equipment and Software (EMC, ESD, Telcom, Environmental, and Safety), Compliance Engr., Annual, 2003. 

Products safety influenced by EMC (EMC tests may also be required for safety compliance) ... 

Due diligence means taking all reasonable steps to ensure conformity. With only a few exceptions, the manufacturer/importer is ultimately responsible for a product s compliance to directives, but with a mark, certificate, or test report from a notified body the suppliers risks are decreased and their defense of due diligence enhanced, should the products safety/EMC conformity come into question. It is the responsibility of notified bodies to accurately interpret directives and standards through testing and certification, thereby ensuring conformity and building consumer confidence. 

If lEC 61508 compliance only is used, it cannot be confirmed that the device functions properly when implemented in the intended application. Reasons for this include improper electromagnetic compatibility (EMC), harmful airborne particulate, power line conditioning issues, plant s lack of design/operation/maintenance experience with the device, and hardware/software limitations as defined in the safety manual. Refer to Clause L.4 for additional issues relating to lEC 61508 compliance assessments. 

Two of many requirements of electronic-system packaging are to ensure that the corresponding equipments are in compliance with apphcable national and international electromagnetic compatibility (EMC)... 

In the Electromagnetic Compatibility Directive (EC 2004) a combination of products installed in a specific place for a specific purpose can be deemed a fixed installation and dierefore not require CE marking, however, the system must still meet the essential requirements of the EMC Directive, dierefore the building s responsible person must construct a Technical Assessment File to demonstrate compliance of the fixed installation with the directive. 

Compliance with the Low Voltage and Machinery Directives will be self-declared following Module A eonformity assessment proeedure. For the EMC Directive the manufacturer has decided to include a notified body in the compliance process to review, underwrite and reinforce the manufacturer s EMC technical assessment. 

This is not strictly a second tier document as its originators do not claim compliance with lEC 61508. However it covers similar ground and is therefore included here. It applies to the safety and performance of medical and electrical equipment. It also applies to electromagnetic compatibility (EMC) of medical equipment. 

Negative tests (failure injections, limit tests, tolerance chain tests, stress tests (including EMC)) mainly show the robustness of components. The failure injection shows the correct function of the safety mechanisms, the correct assumption of the error propagation, the sufficient robustness, the behavior at inadmissible configurations and the compliance of functional and technical limitations. 

Techniques such as spread spectrum ensure compliance with the EMC requirements according to CISPR 25. The use of equalizers allows for adaption to different cable types and lengths. 

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