MIL-STD-461 is the standard that defines the test limits, test levels, and test procedure for various electromagnetic phenomena for electronic equipment used by the U.S. Army, Navy, and Air Force on all platforms (ground, sea, and air). MIL-STD-461F is the latest version. Following are answers to common questions about this often-utilized military EMC standard.
Where can I find MIL-STD-461 and how much does it cost?
The standard is free and approved for public release. It can be downloaded from a number of sites, but we recommend using the official U.S. Defense Logistics Agency (DLA) ASSIST site. This site requires registration and a wait for approval.
What is included in MIL-STD-461?
Test methods cover electromagnetic emissions, which are an unintended, but unavoidable byproduct of every electronic device, as well as electromagnetic susceptibility, which is a measure of the equipment under test’s (EUT) ability to withstand electromagnetic disturbances.
Test methods include specific types of conducted, radiated, transient, and continuous emissions and susceptibility tests. See a full list of test methods on MET’s Military EMC Testing page.
The first few sections define general aspects of the standard and testing, such as terminology, test facilities, test equipment, setup of the EUT, applicable tests for equipment to be used on various platforms, etc.
Section 5 contains a test procedure for each test method, which defines the test equipment needed, instructions for setup, and a procedure for how to conduct the test.
Is compliance with MIL-STD-461 mandatory?
MIL-STD-461 is usually only required when part of a specific military contract between the U.S. military and an electronic equipment manufacturer.
The contract would specify the specific test methods within -461 which need to be performed and passed by the equipment being built for the military.
MIL-STD-461 testing is sometimes voluntarily performed by electronic equipment manufacturers for marketing purposes, to attract possible military contracts and/or for quality purposes, to ensure a rugged design.
I want to voluntarily perform MIL-STD-461 testing and am not worried about my EUT’s susceptibility to electromagnetic disturbances. What are the best test methods for determining compliance with the standard’s electromagnetic emissions requirements?
CE102 and RE102 are the most applicable test methods for this.
CE102, conducted emissions, power leads, 10 kHz to 10 MHz, is performed to verify that electromagnetic emissions from the EUT do not exceed the specified requirements for power input leads, including returns.
This will ensure that the EUT does not cause interference to other electronic equipment operating from the same power source, since the emissions can conduct along the supply lines.
A special piece of test equipment called a line impedance stabilization network (LISN) is connected in series with each conductor of the input power lines to the EUT.
The LISN establishes a 50 Ohm impedance on the power line and has a coaxial measurement port, which allows for connection to a 50 Ohm spectrum analyzer for measurement of the RF emissions.
The EUT is exercised in a way typical of its normal use and the emissions are compared to the limit. If CE102 emissions exceed the limits, the tests are considered not compliant.
RE102, radiated emissions, electric field, 10 kHz to 18 GHz, is performed to verify that electric field emissions from the EUT and its associated cabling do not exceed specified requirements.
This will ensure that radiated emissions from the EUT do not cause interference to other electronic equipment operating nearby.
The EUT and test antenna are set up within a shielded test enclosure, which is internally lined with RF absorbent material.
The shielded enclosure prevents RF ambient noise from entering the test area, while the RF absorbent material reduces RF reflections from the metallic chamber walls, allowing for accurate radiated RF measurements of the EUT emissions with a test antenna.
The test antenna is connected through coaxial cable and chamber wall bulkhead connectors to the spectrum analyzer outside the test chamber.
The EUT is exercised in a way typical of its normal use and the emissions are compared to the limit. If RE102 emissions exceed the limits, the tests are considered not compliant.
For MIL-STD-461 testing for marketing purposes only, does MET issue a test report?
MET can issue a test report and a one-page certificate upon completion of testing.
The test report and certificate would not guarantee acceptance of the product by the U.S. military. However, you are free to use your engineering judgment to make claims of compliance for similar projects, based on the test report and certificate provided.
MET Labs has a reputation for high quality test results and our test reports will increase the credibility of your marketing claims.
Request a free quotation for MIL-STD testing for military or marketing requirements.
IEC 60601-1 3rd Edition for Medical Electrical Equipment Continues to Gain Adoption in Global Markets
The 3rd edition of IEC 60601, issued in 2005, is in various states of adoption by regulatory bodies around the world. IEC 60601-1 is the harmonized standard for medical electrical equipment recognized by public health authorities in most countries. Unlike 2nd edition, the 3rd edition requires a risk management file and process conforming to ISO 14971, the international standard for Application of Risk Management to Medical Devices, in order to show product conformance.
In addition to safety requirements, IEC 60601 includes particular standard requirements for functional safety, software, lasers and EMC.
Following are the known global transition dates.
European Union (EU)
General Standard – June 1, 2012
Particular Standards – Varies, noted by the Official Journal (OJ) of the EU
General Standard with Amendment 1 (EN 60601-1:2006/A1:2013) – June 1, 2018
FDA – From January 1, 2014, FDA requires the 3rd edition of the standard for new product submissions, while for existing products the 2nd edition is still acceptable.
NRTL – In March 2014, OSHA announced through a Federal Register Final Notice its incorporation of ANSI/AAMI ES60601-1 into the list of Appropriate NRTL Program Test Standards. This is the U.S. National Version of IEC 60601-1 + A1.
General Standard – June 1, 2012
Particular Standard – Varies, with a 3-year transition from the date of publication of the particular standard.
Published June 1, 2012, with potential transition in 2017
Classes 3 and 4 + 14 Particular Products – June 1, 2014
Class 2 + 21 Particular Products – June 1, 2015
Class 1 + 19 Particular Products – June 1, 2016
Taiwan & Singapore
Recognize third edition, no transition date announced
MET Labs will continue to provide testing to the 2nd edition of IEC 60601 as long as regulatory bodies continue to recognize it. For those companies launching global products, it may be necessary to maintain a certified 2nd edition test report with local country deviations and also a 3rd edition test report. In those cases, MET offers a dual certification package at a bundled discount.
As a leading medical National Certification Body (NCB), MET can issue a CB Test Report and CB Certificate, for application to CB Scheme participating countries for local marketing approvals.
Most electrical/electronic designs today are subject to electromagnetic interference/electromagnetic compatibility (EMI/EMC) testing.
The first step is to write a test plan. If you are working in the defense industry, a military test plan is usually a contract requirement. If not, you’ll still want one. If you don’t know enough to create one, ask your lab to do it, or to recommend an independent consultant who can help.
A good test plan includes:
- A configuration, mode of operation, and monitoring method, which represents a worst case scenario from an EMC perspective
- Special software, test fixtures, and supporting equipment may be needed to exercise the equipment under test
- A description of hardware to be tested, including peripherals & I/O configurations
- An indication of which external power and data I/O ports need to be tested for each test method
- Required tests
- A definition of failure criteria
- How to monitor, recognize & report failures
- Special needs: Software, power, cooling, etc.
Then, get pricing and scheduling from a leading 3rd party test lab, like MET Labs.
You’ll have to determine what the lab will supply versus what you will supply. You will need:
- Equipment under test (EUT) & spares
- Cables & connectors
- Test fixture (for some programs)
- Tool kit
- EMI suppression supplies – ferrites, copper tape, etc.
- The equipment’s design or compliance engineer or someone else familiar with the product to witness testing
In the Lab
Preliminary testing (pre-testing) is always a good idea. Shortened versions of each test method can be performed to identify failures. Design modifications can be made before final testing is scheduled. A radiated emissions pre-test, often referred to as a pre-scan, is the most common pre-test performed. Even if there is no plan to perform pre-testing for the other test methods, a radiated emissions pre-scan can identify failures and allow for design modifications, which will likely cause the equipment under test to perform better for the other test methods as well.
Then run the full program as specified in the test plan. If you pass the first time, congratulations! If not, don’t take it personally – it’s not unusual, especially with early-stage pre-compliance testing. And practically anything can be overcome.
If you fail a test, do some quick troubleshooting – you may be able to fix the problem right away. Do the easy things first:
- Verify that the EUT is still working properly. This is particularly important with immunity tests that might cause damage.
- Unplug external cables to see if it improves results. External cables, although not designed to do so, act as antennas to radiate emissions and receive RF interference.
- Add ferrites to cables
- Clean mating, conductive surfaces of paint and other materials.
- Add an RF filter module at the power input to the equipment under test to limit RF emissions and protect from continuous conducted disturbances.
- Add a MOVs or other transient limiting device at the power input to protect from transient disturbances.
- To limit leakage, wrap the EUT in aluminum foil
For immunity, back off the test levels to determine the actual failure levels. If you are close, maybe a ferrite will fix things. If not, that’s good information to have – it will help you narrow the possible failure mechanisms.
Don’t be afraid to ask for suggestions. Test engineers at an experienced lab like MET will have seen hundreds if not thousands of products, and know many debug and quick-fix solutions.
MET Labs is a full-service EMC testing lab with multiple convenient locations. Contact us for a free quick-response quotation.
After a long wait, medical electrical equipment manufacturers are looking forward to the Occupational Safety & Health Administration’s (OSHA) expected near-term recognition of one or more labs – including MET Labs – for product safety certifying medical devices to ANSI/AAMI ES60601-1:2005/(R)2012 under the U.S. Nationally Recognized Testing Laboratory (NRTL) Program.
In March 2014, OSHA announced through a Federal Register Final Notice its incorporation of ANSI/AAMI ES60601-1 into the list of Appropriate NRTL Program Test Standards. This version of the standard is the U.S. National Version of IEC 60601-1 + A1.
OSHA delayed NRTL recognition for the U.S. version of IEC 60601-1:2005 (3rd edition) due to what it saw as subjective compliance requirements, as well as statements in the standard that would have required the NRTL to accept statements from the manufacturer without the ability for the NRTL to verify the validity of these statements.
The changes in language introduced in Amendment 1 (496 changes for the IEC standard) allows the NRTL to verify the validity of data accepted from the manufacturer.
Here are some of the key changes in AAMI ES60601-1 as compared to UL 60601-1:
- Clause 9.6 Acoustic Energy – Not included in UL 60601-1
- Clause 9.7.2-.4 Pressure vessels and parts subject to pneumatic and hydraulic pressure – Not included in UL 60601-1
- Clause 9.7.6 Pressure control device – Not included in UL 60601-1
- Clause 9.8 Mechanical hazards associated with support systems – This is a unique mechanical test not included in UL 60601-1
- Clause 11.2.1 Oxygen Rich Environment – An optional additional test if evaluation is not sufficient for proving that the product is not an ignition hazard in an oxygen-rich environment
- Clause 15.3.5 Rough handling test – Additional ascending shock testing and door frame shock testing is included that was not present in UL 60601-1
- Clause 126.96.36.199 Lithium batteries – Not included in UL 60601-1
MET Labs is OSHA-recognized for UL 60601-1, and is expecting to soon be recognized for ANSI/AAMI ES60601-1:2005/(R)2012 as well. Contact us for a free fast-response quote for electro-medical equipment testing and certification for any major market.
To accommodate changes in the Federal Communication Commission’s (FCC) Docket 13-49, the Dynamic Frequency Selection (DFS) test procedure document KDB 905462 D02 UNII DFS Compliance Procedures New Rules has been issued.
The document describes the compliance measurement procedures for performing DFS tests under FCC Part 15 Subpart E Rules required for U-NII (Unlicensed –National Information Infrastructure) equipment that operates in the frequency bands 5250-5350 MHz and/or 5470-5725 MHz.
A U-NII network will employ a DFS function to detect signals from radar systems and to avoid co-channel operation with these systems.
Section 6 provides the parameters for required test waveforms, minimum percentage of successful detections, and the minimum number of trials that must be used for determining DFS conformance.
One of the new requirements is for devices to detect a new radar waveform for DFS testing. Historically, the FCC has required devices to detect 5 radar types. The new rules require detection of a 6th radar type which they designated as Type 1. A previous waveform which was designated as Type 1 is now called Type 0. See the accompanying Table 5.
These rules became effective on June 2, 2014. FCC has established a transition period:
- New devices will be permitted to be approved until June 1, 2015 under the old rules
- Starting June 2, 2016, all devices approved partially or completely under the old rules cannot be marketed, and permissive changes will not be permitted for devices approved under the old rules, unless they meet the requirements of the new rules
MET Labs has the capability to generate the new radar type using Agilent hardware coupled with custom software. Get tested to the latest DFS requirements on new products or update an existing product with a Class II Permissive Change. Get a free quote now.
No new certifications to Version 3.0 are allowable, although existing Version 3.0 certifications will remain valid for the purposes of ENERGY STAR qualification until December 19, 2014. At that time, any product shipped with an ENERGY STAR label must meet Version 4.1 requirements.
The 4.1 specification covers the full suite of cable, satellite, internet protocol (IP), terrestrial, and over-the-top STBs and keeps pace with a quickly evolving market by adding requirements for displayless gateways as well as enhanced functionality like high efficiency video processing (HEVP) and ultra high definition (UltraHD) content transmission, both of which support transmission of richer content.
The 4.1 specification also adopts the EPA’s approach to incentivizing energy saving multi-room configurations and deep sleep and establishes a test method for ENERGY STAR that harmonizes with the Voluntary Agreement for Ongoing Improvement to the Energy Efficiency of Set-top Boxes (VA).
Note: The new spec says STBs must be tested under worst case in terms of configurations and service provider networks. ENERGY STAR Partners may certify STBs that cannot meet the ENERGY STAR requirements in some configurations or on some networks if they assign a unique model identifier to the STBs that do meet them.
MET Labs is an EPA-recognized lab and certification body for 15 ENERGY STAR product categories. Get a free quote now to evaluate your product to the STB 4.1 specification or any other energy efficiency standard, including the Version 6.0 ENERGY STAR specification for computers.
On July 11, 2014, the FCC’s Office of Engineering & Technology (OET) released new guidance giving some consumer electronics manufacturers more flexibility in digitally labeling (e-labeling) their products.
The guidance advises that all devices with an integral (non-removable) screen can now display that label digitally on that screen, and up to three steps deep into the device menu. The user manual must include information on accessing that FCC info, or it can be on the equipment’s Web site.
Removable labels with the FCC info must still be on the product or its packaging when it is shipped and sold.
Formerly, the FCC required equipment that requires FCC certification to have a fixed nameplate or etched label (see the iPhone hieroglyph) listing its FCC ID and any other requirements of operation.
The benefits of e-labeling include:
- Cost savings, especially as devices become smaller
- The potential to provide more information, like recycling or trade-in opportunities
- The ability to update information remotely to address any inaccuracies
The FCC had already permitted e-labeling for a small subset of devices. In 2001, the Commission’s rules authorizing software defined radios (SDR) permitted the voluntary use of e-labeling by device manufacturers.
Meet with MET at Super Mobility Week, North America’s largest forum for mobile innovation, powered by CTIA.
Most electronic devices destined for sale in the U.S. fall under Part 15 (CFR 47) of the Federal Communications Commission (FCC) rules for limits to the unintentional and intentional emission of radiation. However, there are some exemptions that you may be able to take advantage of, depending on the nature of your product. You can find the bulk of this information in Section 15.103 of the rules.
The FCC says it is “strongly recommended” that you still attempt to comply with the rules, regardless of your product type. They have the power to halt sales of your device if the device has been found to cause harmful interference, so proceed with caution.
Here is a simplified description of product types that are FCC exempt from digital emissions testing:
- A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft. Note: wireless devices are subject to other FCC rules.
- A digital device used exclusively as an electronic control or power system utilized by a public utility or in an industrial plant.
- A digital device used exclusively as industrial, commercial, or medical test equipment.
- A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner, etc.
- Specialized medical digital devices (generally used under the supervision of a licensed health care practitioner) whether used in a patient’s home or a health care facility.
- Digital devices that have a power consumption not exceeding 6 nW.
- Joystick controllers or similar devices, such as a mouse, used with digital devices but which contain only non-digital circuitry or a simple circuit to convert the signal to the format required (e.g., an integrated circuit for analog to digital conversion).
- Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines. Digital devices that include battery eliminators, AC adaptors or battery chargers which permit operation while charging or that connect to the AC power lines indirectly do not fall under this exemption.
Although not noted in section 15.103, equipment authorization is also not required for:
- Personal use home-built devices (not kit-constructed) that are assembled in quantities of five or less
- Low-frequency devices that don’t generate timing signals or pulses at a rate in excess of 9,000 pulses (cycles) per second (i.e., 9 kHz)
Note that equipment is not exempt unless all of the devices in the equipment meet the criteria for exemption. For example, if you have a specialized medical digital device with a wireless transmitter, the wireless transmitter still has to be tested.
Please confirm with MET Labs whether you are indeed exempt as there are some caveats to this information.
And, of course, FCC-exempt devices might be required to undergo other types of testing, like product safety certification for U.S. OSHA compliance or EMC testing for CE marking in Europe. Contact MET for a full evaluation of your product line and its intended markets.
The U.S. Department of Defense (DoD) recently issued Change Notice 1 to MIL-STD-810G, Environmental Engineering Considerations and Laboratory Tests. This change notice incorporates more changes – climatic and dynamic – than any previous revision of -810.
A PDF of Notice 1 is available here. It’s a bulging 1,058 pages, over 280 pages more than the Revision G alone and more than twice as many pages as Revision F. Changes are marked by lines in the margins.
Major changes include:
- In Part 1, a significantly expanded section on the Life Cycle Environmental Profile (LCEP)
- In Part 2, all test methods – 500 through 528 – have been updated with a new note
- Only Method 528 can be called out in blanket fashion now
- A rewrite of mechanical shock
- Additional guidance in combining procedures
MIL-STD-810 is used by both the U.S. military and industry to assure that the environmental design and test limits of equipment match the requirements that equipment will face in actual use.
Whether a military product must be tested to Change Notice 1 is dependent on the DoD contract. The DoD uses the product’s life cycle environmental profile and its anticipated deployment region to determine which standard version to specify.
MET Labs is an elite 3rd Party Test Lab for Military and Commercial Aircraft equipment testing, and has top-flight experience working with every top defense contractor and commercial aircraft manufacturer and many of their suppliers. Contact us for a rapid-response quote for EMC or Environmental Simulation testing.
The European Commission is contemplating developing an “eCompliance System” and has published a “Preliminary Reflections on eCompliance” paper on how it would work. Following is a summary of this report that was distributed at the May 2014 meeting of the Group of Notified Bodies under the EMC Directive (EUANB) in Amsterdam.
As products become more complex while product cycles become shorter, the Commission believes it is necessary to explore how compliance with Union harmonisation legislation can be demonstrated/controlled electronically (“eCompliance” concept) instead of the traditional paper-based approach.
The primary objective is to maintain protection of the public interest, while reducing the administrative burden for manufacturers (especially SMEs), Notified Bodies, and authorities.
In an eCompliance context, the process of demonstrating compliance would become more interactive: manufacturers and other operators, Notified Bodies (if involved in the conformity assessment procedure) and authorities would share information and provide real-time feedback to each other.
This may lead to a situation where the border between conformity assessment (ex-ante control) and market surveillance (ex-post control) would not be so clearly defined – authorities may have the opportunity to monitor a product before it is placed on the market.
Various tools (e.g. e-labelling, digital market surveillance, electronic declarations of conformity, etc.) could function in all official Union languages and improve communication:
- Between authorities and manufacturers
- Between authorities and Accreditation/Notified Bodies and between Accreditation/Notified Bodies themselves
- Between authorities
Commercial secrets and confidentiality aspects would be protected by a system of access authorizations.
In order to avoid the proliferation of IT tools, the Commission would examine whether the eCompliance System should be part of the Information and Communication System on Market Surveillance (ICSMS).
Planning for an eCompliance System in Europe is still very preliminary, with many questions to be answered and stakeholders to be consulted. Subscribe to Compliance Today to be kept apprised on further developments in this area.