Requirements for Automated EMC Susceptibility Testing

The EMC susceptibility tests mandated by the European Union (EU) to sell electronic products in Europe are good candidates for automation. For example, just look at the length of the tests themselves: More than 200 frequencies must be tested for radiated immunity and more than 600 for conducted immunity. And if large anechoic chambers are used for radiated immunity testing, the fields must be calibrated prior to testing, which in itself can take some time.

Granted, the approval of harmonized standards in Europe has simplified the task of deciding which tests must be performed to certify product compliance. But by virtue of their complexity, these tests also demand high degrees of accuracy and repeatability that are best provided by specialized EMC software.

For EMC susceptibility, two main standards are involved: the IEC 1000-4-3 for radiated susceptibility, and the IEC 1000-4-6 for conducted susceptibility. The European Norms are EN 50140 and EN 50141, which are essentially copies of the respective IEC 1000-4 documents.

Through the use of software, all operations needed to perform complete immunity tests, from the field uniformity test on the semi-anechoic or anechoic room to the final report, should be performed automatically and with a minimum of intervention. The flexibility of the design should allow you to meet the current and future measurement standards without software upgrades.

Software Features

A complete, modular setup should cover all the aspects of radiated and conducted immunity test operations. Flexibility would allow you to satisfy virtually any existing and future test standard. All the setup data must be easily saved and restored from file, virtually ensuring test repeatability. Table 1 outlines the requirements for automated radiated susceptibility and conducted susceptibility testing.

Add-On Packages

A setup and measurements-results data base for retrieving archived test results, lowering the need for a paper archive.

Automatic control and monitoring of equipment-under-test signals to eliminate the need for user intervention during tests.

Video capture to detect equipment-under-test failures that are visually evident.

Summary

The now mandatory requirements for EMC testing of products being shipped into or within the EU include both radiated and conducted immunity testing. Because of the complexity of these tests, easy-to-use, comprehensive software programs are being developed by many companies. The software package you choose should include the features we have outlined in this article as a minimum and provide you with a path for upgrading to new requirements.

About the Authors

Luigi Bauchiero is a Consultant with Comtest Benelux. He attended the University of Turin, Italy, and began work as a professional consultant in 1985 with Aeritalia, the Italian aerospace company. Mr. Bauchiero is also the author of several software packages for EMC susceptibility measurement and analysis.

Michael Hopkins is Director of Technical Sales at Thermo Voltek. Previously, he was Vice President of Marketing and Vice President of Sales at KeyTek Instrument. Mr. Hopkins has more than 15 years of experience in the EMC field and currently is an active member of several ANSI and ESD Association committees and a corresponding member of NEMA and SAE committees. Thermo Voltek, One Lowell Research Center, Lowell, MA 01852-4345, (508) 275-0800.

Table 1.

Radiated Susceptibility	Conducted Susceptibility
Field or power leveling control measurement modes should be contained in the same package and chosen at any time.	Voltage or power leveling control measurement modes should be contained in the same package and chosen at any time.
Real-time field monitoring should be available in both measurement modes.	Real-time voltage monitoring should be available in both measurement modes, so real applied voltage can be checked continuously.
Field uniformity testing should be conducted automatically. If a software-controlled field probe positoner is used, no user intervention would be required. Field uniformity testing must strictly follow the current IEC 1000-4-3 standard.	Calibration should be conducted automatically. The calibration must strictly follow the current IEC 1000-4-6 standard.
Measurement operations should be performed automatically with user intervention needed only in case of an equipment-under-test failure. The manual mode of operation can be chosen at any time.
Test results should be graphically analyzed and printed in a text form to be inserted in the final report.
A power failure-proof design provides reliability against loss of data, ensuring that no lengthy measurement must be repeated in case of malfunctions.