EMC & Thermal Management


Automotive EMC testing fundamental and best practice


By Marcus Sampson, business line manager for transport, TÜV SÜD T


oday, most countries and regions have electromagnetic compatibility (EMC) testing requirements pertaining to automotive manufacturing. This means most OEMs must be compliant with standards such as the European Union Directive 2014/30/EU or ECE Regulation R10. Component suppliers are also responsible for ensuring their products undergo EMC testing, and must do so in accordance with applicable industry and OEM-enforced standards.


As a minimum, two components are typically required for testing, although this can vary with specific OEM requirements. The test plan must describe all the components and their normal functions/modes of operation, broken down by: ● Inputs/outputs required to trigger the device’s normal modes of operation, plus any relevant details on modes that isolate broadband or narrowband noise


● Methods of measuring component response to input/output actions to establish a baseline for normal operation, such as +/- tolerances


● Signals defined by pin-out diagrams ● Defined orthogonal orientations for the device (depicted with photographs or diagrams)


● Information on power or ground lines requiring transient tests


● Performance requirements based on information about how a component was manufactured, supplier data, environmental conditions for tests, pass/fail criteria, severity levels and relevant safety procedures.


Certain suppliers choose to issue an approval number from their partner OEM to indicate the latter’s acceptance of the test criteria before testing can begin. You can seek counsel on partially completed (and therefore not yet approved) test plans in advance from an EMC testing laboratory. Third-party lab


30 February 2023


associated automakers demand more detailed reports on the individual tests. You will also have to consider various other tight deadlines throughout the course of the project, including macro-deadlines such as time-to-market.


Test methods and standards There are six major areas of EMC testing: ● Radiated RF Emissions (RE) ● Conducted RF Emissions (CE) ● Radiated RF Immunity (RI) ● Conducted Transient Immunity (CTI) ● Conducted Transient Emissions (CTE) ● Electrostatic Discharge (ESD)


Major industry methods governing these tests include: ● The IEC’s CISPR 25 (for radiated and conducted RF emissions)


personnel can review the unfinished plan and make suggestions. However, they cannot conduct any advanced testing, as doing so would put the lab at unacceptable risk of losing its accreditation as a recognized EMC testing provider.


If you are working with a third-party lab instead of in-house, determine these key factors in advance: ● Which party will be providing equipment for generating signals during the test process


● What response monitoring protocols will be utilised (particularly for any tests conducted in an EMC chamber)


As the supplier, you should provide software, equipment or any other informational and operational collateral that will be necessary for the lab to fully understand the component and properly conduct each test.


Testing process steps


Upon receipt of the OEM’s approval number, testing can begin. Ideally, the testing process will go forward exactly as described in the test plan, and the product will meet all of the standards imposed upon it.


However, it may be necessary to make Components in Electronics


adjustments in real time based on unforeseen parameter changes. If the OEM is informed of your intention to adjust the testing process as outlined in the plan, and the manufacturer signs off on the change, it is permissible to change the plan.


For example, a motor for a power window is expected to be run continuously clockwise as part of a test in the plan, but it can’t because it’s attached to a fixture and can’t travel very far until it hits a hard stop and must be reset. The OEM must be informed of the issue and told why a change is necessary.


Another example could be that the required orientation of the device during testing prevents the wire harness requirements from being met. In either case, the OEM must both be informed of the issue and told why a change is necessary.


Close communication between the testing lab, supplier, and OEM is critical. In many cases, an OEM will require continuous updates on test passage or failure, sometimes as immediately as 24 hours or less after each test is conducted.


After being informed of a test pass / fail status, you may have a few more days before


● ISO 11452-xx (for RF immunity) ● ISO 7637-x (for conducted transient immunity and emissions)


● ISO 10605 (for electrostatic discharge) ● ISO 16750-2 (if electrical loads are involved, as in some cases such as reverse voltage and ground offset)


These requirements can be situational, and the exact parameters must be worked out between the supplier and the OEM. Some manufacturers require compliance with their own unique internal specifications, such as: ● General Motors (GMW3097 and GMW3172) ● Ford (FMC1278) ● Fiat Chrysler (FCA CS 00054) Jaguar/Land Rover (JLR-EMC-CS)


Your test lab (whether you have a lab in-house or use a third-party facility) must meet ISO 17025 minimum requirements for the lab operations. Automotive EMC tests for emissions and immunity are generally conducted at a distance of one metre from the device, at a fixed height. A typical test level for radiated immunity is 100 volts per metre.


www.tuvsud.com/en-gb/industries/ mobility-and-automotive


www.cieonline.co.uk.uk


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