CISPR 11 – Edition 6.0 and its Two Amendments
The International Electrotechnical Commission (IEC) has a unique Technical Committee that is called the International Special Committee on Radio Interference (CISPR). Underneath CISPR, there are a number of Subcommittees, one of which is Subcommittee B (CISPR B), bearing the title of “Interference Relating to Industrial, Scientific, and Medical (ISM) Radio-Frequency Apparatus, to Other (Heavy) Industrial Equipment, to Overhead Power Lines, to High Voltage Equipment and to Electric Traction.” The scope of CISPR B’s work chiefly focuses on the International Standard, CISPR 11, Edition 6.0 (2015-06) and Amendment 1 (2016-06).
This article is an update on the latest Amendment to CISPR 11, Amendment 2, and the anticipated activities of CISPR B in the coming year.
Administrative Matters
In general, CISPR B meets once a year as part of the Plenary meetings for CISPR and its Subcommittees. Many of the Subcommittees have Working Groups (WGs) where discussions leading to the amending of existing standards and the development of new standards take place. WGs may, and oftentimes do, meet more frequently than once a year.
CISPR B includes two WGs, as follows:
- WG 1 – Industrial, Scientific and Medical (ISM) Radio Frequency Apparatus – Mr. Steve Hayes – Convenor
- WG 2 – Interference from Overhead Power Lines, High-Voltage Equipment, and Electric Traction – Dr. Heesung Ahn – Convenor
The work of CISPR B also includes several ad-hoc groups (AHGs), which are:
- AHG-3 – Semiconductor Power Converters
- AHG-4 – WPT (Wireless Power Transfer)
- AHG-5 – In-Situ Measurements
- AHG-6 – Measurements of Large/Heavy EUTs
Product Classes and Groups
Group Separation
Group 1 equipment contains all equipment in the scope
of CISPR 11 which is not classified as Group 2 equipment. Group 2 equipment contains all ISM RF equipment in which radio-frequency energy in the frequency range 9 kHz to 400 GHz is intentionally generated and is used or only used locally, in the form of electromagnetic radiation, inductive and/or capacitive coupling, for the treatment of material, for inspection/analysis purposes, or for transfer of electromagnetic energy.
Class Separation
Class A equipment is suitable for use in all locations other than those allocated in residential environments and those directly connected to a low-voltage power supply network which supplies buildings used for domestic purposes. Class B equipment is suitable for use in locations in residential environments and those directly connected to a low-voltage power supply network which supplies buildings used for domestic purposes.
CISPR 11, Amendment 2
Amendment 2 to CISPR 11 was released in January, 2019. It addresses the following two areas of interest in the standard:
- Requirements for semiconductor power converters (SPCs)
- Improvement of repeatability for measurements in the frequency range 1-18 GHz
SPCs
Additional information was added to CISPR 11 to include test requirements for the following types of equipment:
- Power conversion equipment intended for assembly into photovoltaic power generating systems, such as grid connected power converters (GCPC) and DC to DC converters; and
- GCPCs intended for assembly into energy storage systems.
Repeatability of Measurements from 1 – 18 GHz
As a result of Amendment 2, the peak detector will be mostly used for preliminary measurements while the number of final measurements (with the Log Average [LogAV] detector) has been increased from two frequencies to a maximum of seven frequencies. The second amendment extends the frequency range of the final weighted measurement from 10 MHz to 20 MHz and it also defines the same seven final frequency ranges for the Amplitude Probability Distribution (APD) method as already defined for the LogAV method.
Also, the peak limit in Table 13 is changed to a constant value of 70 dBuV/m. The requirement of a final peak measurement in the range 11.7 to 12.7 GHz has been replaced by a requirement of an additional weighted measurement at the frequency of the highest peak emission in the 11.7 to 12.7 GHz range.
Finally, the distinction between preliminary and final peak measurements has been replaced with “make all peak measurements on all azimuths for 2 minutes.”
Other Elements in Amendment 2
Amendment 2 adds the following new definition to the standard:
“Power Conversion Equipment – electrical device converting one form of electrical power to another form of electrical power with respect to voltage, current, frequency, phase and the number of phases.”
The Amendment also adds a new table to the standard, Table 19 – Applicability of measurements at DC power ports, and replaces Table 13 (Electromagnetic radiation disturbance peak limits for Group 2 equipment operating at frequencies above 400 MHz) with a new Table with the same title, but no requirements between 11.7 and 12.7 GHz.
Amendment 2 also replaces the existing Table 14 (Electromagnetic radiation disturbance weighted limits for Group 2 equipment operating at frequencies above 400 MHz) with a Table 14 with the same title but with revised footnotes. Table 15 (Electromagnetic radiation disturbance APD level corresponding to 10-1 limits for Class B Group 2 equipment operating at frequencies above 400 MHz) has been replaced with a new Table 15 (same title) with additional footnotes.
Figure 12 (Decision Tree for the measurement of emissions from 1 GHz to 18 GHz of Group 2 equipment operating at frequencies above 400 MHz) has been replaced with a new Decision Tree emphasizing “Final LogAV weighted measurements” and “Final APD weighting measurements.” This new Decision Tree is shown in Figure 1.
Lastly, the title and text of 9.4.3 (Preliminary measurements) has been replaced with the title “Peak measurements” and all new text. And the title and text of 9.4.4 (Final measurement) has been replaced with (9.4.4 – Weighted measurements) and all new text.
On-Going Technical Considerations for CISPR 11 WG 1
One of the technical issues being considered by WG 1 is “Measurement Requirements for Robots.” Some WG 1 members believe that a separate product standard (different from CISPR 11) should be considered. Others think that they should not consider functional safety requirements. At this time, it seems that the general consensus is that CISPR 11 should cover the emission requirements of robots, but that functional safety issues should be addressed in another international standard.
A second area of concern for WG 1 is “radio enabled products.” The WG is considering the technical aspects of including this type of equipment in CISPR 11 but taking into account comments from other subcommittees in CISPR.
A third area of interest for WG 1 is wireless power transfer at a distance, or WPTAAD. This technology is concerned with identifying certain ISM bands that could be used for applying microwave energy (radiated energy) to power or charge mobile devices (over short distances) used in homes and businesses. WG 1 is considering coexistence of WPTAAD and existing radio services as one technical issue. Specific areas of interest include 915 MHz, coexistence with WiFi, and inter-/cross-modulation effects.
AHG 3 in CISPR B is looking at supplementing CISPR 11 with requirements for semiconductor power converters. The AHG is considering safety requirements in addition to measurements of unsymmetrical voltages. Meanwhile, AHG 4 is looking at a supplement of CISPR 11 for requirements of air-gap wireless power transfer, while AHG 5 is working on “Consideration of in situ measurements,” which will include measurements of electric fields below 30 MHz including using a rod antenna. The last active AHG (#6) is concerned with measurements of large size/high power EUTs.
On-Going Technical Considerations for CISPR 11 WG 2
WG 2 is actively working on maintaining and improving CISPR Technical Reports (TRs) 18-1
and 18-2. CISPR TR 18-1:2017 is titled Radio Interference Characteristics of Overhead Power Lines and High-Voltage Equipment – Part 1: Description of Phenomena, while CISPR TR 18-2 is titled Radio Interference Characteristics of Overhead Power Lines and High-Voltage Equipment – Part 2: Methods of Measurement and Procedure for Determining Limits.
Conclusion
Amendment 2 of the CISPR 11 standard is the next step in a long series of improvements to the internationally recognized standard on ISM electromagnetic emissions. The Amendment makes some definite changes to the technique for measuring emissions in the range from 1 to 18 GHz for Group 2 equipment operating at frequencies above 400 MHz. The user of the standard gets to choose the FINAL LogAV weighted measurements avenue or the FINAL APD weighting measurements avenue.
Finally, it should be noted that the publication of EN 55011: 2016 (sixth edition) was ratified by the European Commission on February 15th, 2016.
The date of withdrawal of the fifth Edition was set as February 15th, 2019. Therefore, the sixth Edition became mandatory in the European Union after
that date.
