In this article Protections Techniques & FAQ about CE Mark are presented. CE Mark is the manufacturer's declaration for certain products sold within the European Economic Area since 1985 in according to the EC directives.
1. PROTECTIONS TECHNIQUE SUMMARY
1.1 LIMITATION OF INTERFERENCES REALIZED BY THE CIRCUIT
* Enclose the noise source in one screened zone
* Filtrate the conductors that get out from the circuit
* Limit the signals rise times
* Equip the relay bobines and the contacts with devices attenuation
* Screen and/or Schermare e/o weave (twist) the signal's conductors
* Put on the ground the cables' screen
1.2 LIMITATION OF THE EMISSIONS IN THE DIGITALS CIRCUITS
* Reduce at the minimum the earth inductance using a plan or, better, one grill extensive
* Install nearby to each integrated a despairing condenser.
* Reduce at the minimum the clock circuits meshes(loop)
* The driver of I/O (entrance/exit) must be installed as nearer as possible to the exit connectors.
* Using fast clock as can.
* Hold the clock circuits far from the exit connectors.
1.3 LIMITATION OF THE INDUCED INTERFERENCES ON THE CIRCUIT
* Weave and screen the signal conductors
* Put on the ground to just a one extremity the weak signal conductors screen to a low frequency
* When the weak signal conductors and the noises conductors are in the same connectors, separate them interposing between them the earth connectors.
* Take the signal conductors screen across the connectors on the separated pin.
* Avoid the common earth conductors between the equipments to high level and those a low level
* Keep separated the electrics circuits earth from the metallics structures earth
* Keep the earth conductors as shorter as possible
* Maintain the source and the cargo balanced towards the earth
* Enclose all the sensibles circuits in the screening zones.
* Filtrate or decouple the conductors that entry in the screened bin
* Maintain as shorter as possible the termination conductors of the cables screens
* Avoid the grounding' mash reducing the area to the minimum.
Why is the CE required?
Because there are the CEE directives that, acknowledged in Italy with the legislatives decrees and others proceedings, impose it. That to make uniform the safety of products which can be used in the European Community countries.
What are the CEE directives?
There are documents that fix the products essentials required and refer to the norms specifics, products norms, for all others characteristics that must have.
How identify the directives to applicate?
In base to the product type or the products family to realize. There are directives concerning the "medicals devices", "the toys", "the gas equipments", etc. There are directives more generals, for example on the "electromagnetic compatibility" to which is applied to all the products of electric/electronic type. Another directive is the "directive low tension".
How to make the CE marking?
The CE marking appends to a product presume that the product is conform to the directives and norms applicable. Therefore the signature of the marking is like a final act only after it proved the conformity. .
How to prove the conformity?
The conformity is proved through the procedures that can concern the producer only or a third agency upon the request the conformity DECLARATION or CERTIFICATION. The procedures are contained in the modules (A, B, C...H modules) came from a Community Decision.
What is "the conformity declaration"?
It's an act with which the constructor declares that that product is conform to the directive (or directives) and applicable harmonizes norms.
What are the "harmonizes" norms?
Are norms that, after the publication in the Official Gazette of the European Community, are acknowledged by the community members. Their application guarantees the product conformity presumption.
How is applied the directive 89/336 CEE on the electromagnetic compatibility?
The directive 89/336/CEE is between those which consider sufficient the conformity declaration. Therefore the producer must (I save some exceptions):
- Project and construct the apparatus so that is immune to the disturbs and doesn't provoke disturbs to others products.
- Follow the experiments and the e.m. compatibility measures applying the harmonizes product norms.
- Draft and sing the conformity declaration.
- Append the CE marking.
- Keep on disposition for the eventual controls all the project documentation and project construction, the experiments results and their modality of calculation for 10 years.
Note: Beyond the directive on the electromagnetic compatibility an electric/electronic product is the subject at least at the directive for the safety against the electrics risks; the CE markig must cover also this directive.
How satisfy the directive 89/336/CEE if for that apparatus aren't the harmonizes norms?
In this case are applied the generic harmonizes norms, valid for all the apparatus.