Product design
31 December 2021

EMC: how to survive its qualification tests?

Your product will soon be on the market, you are in the “final phase”… Soon, you will go to the labs, to ask for the “stamp of approval”… Until then, everything is simple and clear.  But this “stamp of approval”

EMC qualifitication tests

Your product will soon be on the market, you are in the “final phase”…

Soon, you will go to the labs, to ask for the “stamp of approval”… Until then, everything is simple and clear. 

But this “stamp of approval” does not come so easily. Do you have to certify the product?  Pass qualification tests? EMC?


Any IoT product (or not), put on the market, must be certified. To be certified, it must show that it is compatible with its EMC environment.

To do this, it must go to the lab and pass qualification tests, EMC, but also Radio, and Secu-Elec.

But what is all this?


What is EMC?

EMC is electromagnetic compatibility.

Meaning the compatibility of a device with its electromagnetic environment.

In other words, it is its capacity to coexist, amongst other electrical and electronic devices.

Its capacity not to emit too much disturbance, and to be immune to the disturbances of others.

Yes, but it’s still not very clear. 

To understand the idea of disturbances, of noise, we can compare it to the image of water. 

Imagine a drop of water. As it falls, it produces eddies (the surface of the water is no longer flat). These eddies are disruptive and can interfere with the elements in the water. 

The analogy of the electron and the drop of water is explained in the excerpt from the webinar at the end of this article.


How does an EMC test work?

EMC testing is something you do in a lab, namely in an anechoic chamber, aka. The torture chamber.

You probably already know that. And then it’s up to the lab to master the test.

But, once in the chamber, do you know what will happen to your product?

Do you know what it should do and how? Because putting in the standard software is not enough.

What’s more, the lab doesn’t know your product. It is up to you to be the actor of your qualification.


In the webinar, we explain to you, through an analogy for the less technical, and then “concretely” for the more technical, how to test your product.

As well as how to adapt your product and its behaviour, so as to allow EMC tests, but also Radio tests. The objective is to be ready: to have a product ready to go, but also to have a ready setup.

Because the qualification phase is very expensive. You have to be ready, and not start asking yourself the question the day before.


What happens during the EMC tests?

During the tests, there are 2 phases:

  • Emission: do not make too much noise.
  • And immunity: not being disturbed by the noise of others

Yet it is not only the radiated noise that will be tested! There is also the conduit, the harmonics, the flickers and the fast transients in bursts…

The purpose of each test is to confront your product with a situation that it may encounter in real life. For a given product, the objective of EMC testing is to probe the behaviour of your product in a situation it will encounter. It is therefore not a question of burying your head in the sand or looking the other way during the test. You have to understand the test and know what you are testing, in order to test it correctly.


Successful EMC testing: the levers and our advice

Through the first part of the webinar and the analogy of water, you will have understood what makes noise, and how to make less noise.

To control this noise, you must act: 

  • Less fast
  • Less loud
  • Less often
  • Better controlled
  • Better insulated 

To go further, the rest of the webinar can help you. 

We give advice and rules to follow for the different steps when carrying out the project.

We also discuss some rules for the design of your product.

You will understand what EMC tests are and, above all, how to prepare for them and give yourself every chance of passing them.


What other tests are needed for the qualification tests?

If, like us, you make radio products, you will have to check that the radio “works” well. Without disturbing others.

You have probably already met and experienced the EMC setup. 

However, the radio setup is often unknown. It is not mastered (or not as well).

In the second part of the webinar, we lift the veil on this opaque part for the uninitiated. We will explain how to proceed and give yourself every chance of success.

Lastly, we talk about Electrical Safety testing and share some sound advice.

The aim is always the same: to understand the tests so as to be better prepared.


How to choose your laboratory?

Or rather how to get the best from your laboratory?

You probably know all the labs in your area.

Around us, there are:

  • The big ones, of course – LCIE, Emitech 
  • The smaller ones, from the region – SMEE and AEMC…
  • But also those linked to the student world – Esynov in Valence or Nexio in Grenoble, which can accompany investigation and pre-qualification tests only.
  • There is also SGS, the very large Swiss neighbour, installed in Aix (for Secu-Elec), 

You will have chosen your lab on the basis of the quote and the price. But don’t forget the other parameters, namely : 

  • Experience in YOUR field,
  • Accreditations, especially if you are going abroad
  • Performance… Not all labs are equal in terms of Radio testing.
  • And the feeling

Our advice: choose the one that will be best able to accompany you.

Also, as the subject of testing is complex, we advise you to stay in France and not to add the language barrier.

Our advice: don’t hesitate to separate the batches.


For example :

  • Radio and EMC tests in the same place – France.
  • The electrical safety part, independent, where you want… But in France, it’s better… 
  • And then the notified body, those who will do the EU type examination, independent too… 


Finally, and most importantly, take the time to give them the information. ALL the information.

Why? There can be a big difference between two lab quotes.


Most of the time, it is because your request was not precise enough, that the labs have planned to do certain tests (in doubt..) that others have not planned them (in doubt…)

Do not leave room for vagueness. Your estimate will grow accordingly.

How much does a certification cost?

Between 8k€ and 50k€ in the IoT domain.

That leaves some margin.


However, depending on your product, its complexity – radio in particular – and the number of countries targeted, the difference can be significant.

To avoid extra costs and wasted time: aim for the right target.

Refine your international strategy, take note of the estimated costs and then ask your lab for a quote for the tests you need to carry out…

This is not a wish list.

Ask for the necessary and indispensable tests. For the desired certification.

Control your request. Be involved. Don’t just ask for a stamp of approval!


How to prepare for EMC and RADIO testing? Our tips.

From our experience, we have several practical tips: 

  • Anticipate and prepare. One to two months before the tests. Prepare specific hardware and software  
  • Understand the purpose of the tests: what real-life issue is being tested? Is the level of testing sufficient? Establish a set-up and put the product in the state that allows for real testing.
  • Make sure that your product is stable and durable enough. It is often the case that malfunctions are caused by an unreliable product. In an EMC room, you should be doing EMC, not debugging.
  • Control the geometry of your product. If the geometry is unstable, your test will also be unstable, and the success of the test may not be reproducible. So get all your cables under control! All cables should be tied and secured. 
  • It is always better to have pre-qualification tests, to “de-risk” the product, but also the setup, because unless you have a lot of experience, it rarely works the first time.
  • Create a frequency map. Switch to the spectrum analyser and find out the exact operating frequencies, which will facilitate the investigation.
  • During the trial, ensure to provide equipment. Bring your soldering iron, EMC components, and programming probe to the test.
  • During pre-qualification, allow for margin! Margin for the noise emitted, but also margin in immunity, to have margin of operation.
  • Follow the tests. Be really present. Note everything – especially your modifications.
  • Last but not least, think about EMC and testing from the product design stage: Design for EMC, because after that it is often too late – too expensive, too big and no room.


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