Room Testing for EMC Standards and Automotive Components
Automotive standards for electromagnetic compatibility (EMC) are mainly developed by CISPR, ISO and SAE. CISPR and ISO are organizations that develop and maintain international standards of use. SAE develops and maintains standards for use primarily in North America. In the past, the SAE has developed several EMC standards, which were eventually submitted to CISPR and ISO for consideration as an international standard. When SAE standards become international standards, the equivalent SAE standard is withdrawn as a full standard and is reserved for use in documenting differences in international standards.
Each vehicle manufacturer has internal standards that determine the levels and tests that the components used in their vehicle must meet. As with government standards, these documents often refer to CISPR and ISO documents, which differ in scope or test levels. In the past, a US-based vehicle manufacturer has applied SAE documents to corporate standards. Most of today
USA-based vehicle manufacturers worldwide market. For this reason, they refer to CISPR and ISO standards in their internal standards, and this applies to other established and developing manufacturers.
Road vehicles – Vehicle testing methods for electrical distortion from electromagnetic energy with impact spread – Part 1: General principles and terminology
N / A
SAE J551 / 1
N / A
Chapter 2: In-Car Radiation Sources
SAE J551-11 (Note 1)
Immune test in an anechoic chamber
Car shock absorber covered room
Part 3: Built-in transmitter simulation
SAE J551-12 (Note 2)
Vehicle Absorbent Lined Shielded Enclosure (ALSE) required
Car shock absorber covered room
Part 4: Mass Flow Injection (BCI)
SAE J551 / 13 (Note 3)
The test is designed for machines and vehicles that are too large to fit into a standard EMC.
Open Test Area (OTS) or Vehicle Absorbent covered room
CISPR 25 and CISPR 12
The CISPR 25 is typically not used for regulatory purposes, but is commonly used by vehicle manufacturers to ensure good performance of vehicle-mounted receivers. If the radio installed in the vehicle, boat or other device does not perform reliably, consumer satisfaction and consequently product sales may be damaged.
Both CISPR 12 and CISPR 25 relate to vehicles operating on internal combustion engines (land-based vehicles), boats working with internal combustion engines (vehicles running on the water surface), and devices (but not necessarily) that work with internal combustion engines. for the transport of people). This latest category includes compressors, chainsaws, garden equipment and so on. It contains. CISPR 12 applies to all of these devices, as this may affect the performance of nearby (external) receivers. However, CISPR 25 should only be considered for products containing built-in receivers. For example, a chain saw with an internal combustion engine (but without built-in receivers) must meet the requirements of CISPR 12, but CISPR 25 does not use any built-in receiver for this saw.
CISPR 12 emitted emission measurements are made at 3-meter or 10-meter test distances. Measurements are normally made in an outdoor test area (OTS) or ALSE in an absorbent coated shield if the ALSE can be correlated with an OTS. Measurements can also be made for boats for water. The correlation of ALSE with an OTS has been a topic of discussion within the group of experts responsible for maintaining CISPR 12 over the past few years. The specification does not currently provide a method for obtaining this correlation. A working group is tasked with developing a method for associating ALSE with OTS; However, this may take more than a few years and we are expecting CISPR 12 7 then published in th Version.