This unit provides a brief overview of the EMC directive "EMC 2004/108/EC, for products that are to be used in the European Community.
The EMC directive relates to a set of harmonised standards, that is standards that apply to all member states of the European Union (EU). The directive itself is relatively short and is mainly concerned with legal issues. A useful link to the official EU web site is:
http://ec.europa.eu/enterprise/newapproach/standardization/harmstds/index_en.html
A list of the current harmonised standards that fall under the EMC directive may be obtained from:
http://eur-lex.europa.eu/LexUriServ/site/en/oj/2006/c_314/c_31420061221en00310047.pdf
The harmonised standards define requirements and test conditions for all aspects of EMC. We shall make use of these throughout this unit. They are available from the British Standards on Line web site.
The EMC directive is concerned with:
For the EMC directive, electromagnetic environments are classified as:
This environment is reserved for heavy industrial locations that do not connect to any public voltage supplies.
This environment includes locations that are directly connected to the main public voltage supply network. In the European Union, Offices, and most companies, including SMEs, fall into this category.
We shall be concerned with Class B environments in this module.
Emission categories are broadly classified as:
Radiated
Line Conducted
Harmonics
Voltage Fluctuations
In this module we shall discuss and apply standards relating to the above emission categories and relate them to specific design examples.
A product should be capable of operating as intended in its electromagnetic environment, that is it should be immune to emissions from products and equipment operating in the local environment.
There are six different categories of Immunity:
We shall discuss and apply standards relating to the above immunity categories and relate them to specific design examples, in this module.
The performance of a product, when tested to determine its immunity, is described by the following performance criteria:
During testing, normal performance of the product, within the specification limits, are maintained. There can be no degradation of performance at all during the test.
During testing, temporary degradation, or loss of function or performance of the product is allowed, provided it recovers without any human intervention, that is the product recovers and performs normally of its own accord.
During testing, temporary degradation, loss of function or performance that requires operator intervention or system resetting for the product to recover normal operation, is allowed.
Degradation or loss of function which is not recoverable due to damage to the product, equipment, components, or software (failing criteria).
We shall discuss and define testing methods and relate them to specific design examples, in this module.
Updated: 26/05/07 RJH
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