EMC (Electromagnetic Compatibility) Testing

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What is EMC Testing?

EMC testing or Electromagnetic Compatibility testing is the process of evaluating the electromagnetic emissions and susceptibility of electrical or electronic equipment. The goal of EMC testing is to ensure that the equipment does not emit excessive electromagnetic interference (EMI) that could disrupt the operation of other nearby equipment, and that it is not susceptible to EMI from other sources

Why is EMC Testing Important?

EMC testing is important for a number of reasons, including:

  • Preventing interference between different types of equipment: If a piece of equipment emits too much EMI, it could interfere with the operation of other nearby equipment. For example, a medical device could emit EMI that could interfere with a nearby pacemaker.
  • Ensuring that equipment is safe to use: If a piece of equipment is not properly shielded, it could be susceptible to EMI from other nearby equipment, which could cause it to malfunction.
  • Ensuring that equipment meets regulatory requirements: In many countries, there are regulations that require electrical and electronic equipment to meet certain EMC limits.

What are the Benefits of EMC Testing?

There are many benefits to EMC testing, including:

  • Preventing equipment failures: EMC testing can help to prevent equipment failures that could be caused by EMI.
  • Improving product quality: EMC testing can help to improve the quality of products by ensuring that they are not susceptible to EMI.
  • Reducing costs: EMC testing can help to reduce costs by preventing product recalls and warranty claims.
  • Gaining a competitive advantage: EMC testing can help businesses to gain a competitive advantage by ensuring that their products meet regulatory requirements and are not susceptible to EMI.

What are the Costs of EMC Testing?

The costs of EMC testing can vary depending on a number of factors, including the type of equipment being tested and the complexity of the testing. Please see our Test Pricing page for further guidance on costs.

What's involved in the testing?

We measure the amount of electromagnetic energy emanating from your product. This energy can be emitted from the unit itself, from the AC or DC power cable or any signal cables such as USB, HDMI or Ethernet that may be attached to the product in normal operation.

As supplied, the unit must be in a “worst-case” state for testing; that is to say that all functions must be operating at their highest level to maximise any potential emissions.

The purpose of EMC Immunity testing is to ensure that the product will function correctly in the presence of electromagnetic interference (EMI).

The product will be subjected to a range of different types of EMI and the behaviour of the product will be monitored in order to confirm that it is operating as intended. The actual product specification forms a critical part of the performance assessment and it is important to quantify any degradation that may occur under duress. We assess the product operation using performance criteria.

What are the Performance Criteria?

The following statement is quoted from the EMC compliance standard EN61000-6-1 and gives an indication of what information is required:

A functional description and a definition of performance criteria, during or as a consequence of the EMC testing, shall be provided by the manufacturer and noted in the test report.

No degradation of performance or loss of function is allowed below a minimum performance level as specified by the manufacturer, or what a user of the product would reasonably expect when the equipment is used as intended.

This criterion is used to judge whether the product is operating normally both during the test, and after the test.

No degradation of performance or loss of function is allowed, after the application of interference below a performance level specified by the manufacturer, or what the user of the product would reasonably expect when the equipment is used as intended.

This criterion is used to judge whether a product still operates correctly after a test is complete, and some degradation is permitted while the test is in progress, provided that the product returns to normal after the test is complete.

During and after the testing, a temporary loss of function is permitted, provided that the product function is self-recoverable, or can be restored to normal operational state using the controls normally available to the user, or a power cycle of the product by the user in accordance with the user manual.

This criterion is very similar to criterion B, however operator intervention is permitted to recover function. In more basic terms, the product must work after we’ve tested it! If it breaks during test, it’s game over.

What can happen to my product during testing?

During testing, different types of applied electromagnetic interference can cause a range of product malfunctions. Typical examples of problems are as follows:

  • Loss or corruption of communications data
  • Excessive variation of analogue measurements beyond product specifications
  • Phantom input signals
  • Inadvertent change of product state
  • Loss of processor function
  • Loss of display function
  • Inadvertent triggering of alarms
  • Loss of configuration data or spontaneous changes of settings
  • System reset
  • Damage to I/O ports or loss of function
  • Catastrophic failure of critical components

What happens after the test?

After testing, the product is packaged back up and placed in our warehouse while we do the paperwork and generate the reports (assuming the product passed of course!) to await return to the customer or disposal, depending on what we’ve been instructed to do.

Unfortunately, some of the tests performed on the product are destructive by nature, and can render the product completely nonoperational, or severely reduce the life of the internal components.

For this reason we strongly recommend that if the product is returned to you after test that the sample used is not placed on sale or raided for spare parts.

What do I need to provide to the lab?

We need detailed information about the product to be able to correctly perform EMC testing. Information such as the following is vital:

  • What communication interfaces the product has
  • Length of all cables when the product is in normal service
  • Product power requirements (AC/DC, Voltage, Power)
  • Indoor or outdoor use product
  • If there are any magnetically sensitive components such as Hall-Effect sensors or dynamic microphones
  • Where the product is intended to be used, such as a domestic, business or heavy industrial environment
  • If you know them, any specific Directives or Standards that apply to your product
  • A detailed description of the product’s functions
  • Product configuration and setup block diagram

Ready to test?

Have all your information together?

Click the button below to go to our EMC Product Information Form, where you can enter all the details about the product ahead of your test booking.

If you’ve not spoken with us directly yet, don’t worry! We will use the information you provide to generate a bespoke quotation to suit your testing requirements.

If our engineers have any questions needed to refine things, then we’ll get in touch as soon as possible to discuss these and any questions you may have about the process.

CASS Industries Ltd - CE/UKCA Testing Lab

CASS Industries is a local test lab in Manchester offering compliance testing services.

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CASS Industries Limited
Unit 1, Bankside Business Park
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