Witnessing EMI Testing Properly Adds Value

Witnessing EMI Testing
Witnessing EMI Testing

Witnessing EMI/EMC testing is a complex task.  Conducting this task properly can add value to your product development efforts.  More often than not products fail their initial testing.  Because of this, iterations of redesign and retest are required.  This can result in budgetary and scheduling issues for your design team and delay getting your product to market.

What is EMI/EMC Testing?

Let’s start by defining what testing is.  The word test has many definitions.  The definition critical for our subject is “a procedure for critical evaluation“.  There is significantly more going on than the pass/fail exams we took in college.  This process verifies that the product will meet design specification when operated in its intended environment and validate that it meets or exceeds customer requirements. 

When products experience issues in the field they can interfere with other equipment in their environment.  They can also be susceptible to radio frequencies that result in unexpected behaviors of the product.  These issues can result in property damage, injury, and death.  They can also result in product recalls, product liability cases, and fines.  Therefore properly conducted testing is of great importance.

Have a Plan – A Test Plan

The first step is to understand what testing is to be accomplished.  This will require reading and comprehending the standard and its requirements.  Once that has been done creating a test plan is essential.  This is because it is important to clearly communicate to lab personnel important information that is specific to your equipment.  This would include:

Testing to be Performed

This not only would include what testing is to be performed but document required pass/fail criteria.  This is because many standards will have different requirements for various classifications of equipment. 

Description of Equipment to be Tested

This should include a general description including model, serial number, and version numbers for hardware and software.  It should also include power requirements and overall size of the equipment.

Modes of Operation

This section should define all operational modes of the equipment, control settings, required interconnections.  It should also include any grounding or load requirements.

Performance Checks

Remember that we are trying to verify and validate the performance of the product.  Testing the equipment in an idle mode will not accomplish this goal.  Therefore it is important to provide simulation equipment to exercise the test item during both emissions and susceptibility procedures.

Susceptibility Criteria

It is important to define what your equipment’s acceptable level of operation when conducting susceptibility testing.  Often requirements for classes of equipment are established in the test standard.  This will inform the lab what the pass/fail criteria for the test will be.

Electrostatic Discharge Schedules

It is a good idea to document test points for Electrostatic Discharge (ESD) testing.  The documentation should include points where likely discharges from human contact would occur.  This documentation instructs the lab personnel to conduct a test that returns valid data.

Witnessing EMI Testing – Do the Work

Sitting in the waiting room of a lab plinking on a laptop is not providing any value to test activities.  A test witness should go to the lab prepared to work.  Communicate with the lab personnel what is to be done and make sure they are clear about the details.  Set up the test equipment and ensure it is operating correctly.  Place the equipment into a required mode of operation and check to see that simulation equipment, monitoring equipment and loads are behaving properly.  It is important to assist in monitoring the test item to capture any intermittent failures when performing susceptibility testing.

Data Gathering and Troubleshooting

The real challenge when witnessing EMI/EMC testing is when a test fails.  Time management is critical.  Selecting the best avenue for isolating and analyzing the cause of the failure can best utilize that time.  While you may not be able to “solve” the problem at the lab, you can identify causes of the failure.  You can also identify mitigation techniques that should be considered for design modification.  All of this activity should be documented and included in a final report.

CVG Strategy

It can be a challenge to perform witnessing of EMI/EMC testing in the new reality of Covid-19.  Travel of essential personnel to test facilities is often not an option.  CVG Strategy test and evaluation consultants are ready to help.  We are partnered with local labs to provide test program management and test witnessing services.  We offer a variety of test documentation products including our EZ-Test Plan Templates.

Our subject matter experts have decades of experience in aerospace, automotive, defense, and commercial applications.  They can help you with design issues by performing product evaluations and susceptibility analysis.  Contact Us today to see how we can help.

Tech Standard Development Open to U.S. Companies

Tech Standard Development Open
Tech Standard Development Open

The US Department of Commerce has announced that tech standard development is open to participation by U.S. companies.  This new rule is designed to allow U.S. technology companies to influence the future of cutting edge technologies.

The Role of Standards in Technology

Standards are created to establish minimal criteria for functionality, interoperability, and safety.  They also establish methods of test and evaluation to ensure those criteria are met by products.  Because these standards effect the manner in which products are specified, it is important that U.S national security and foreign policy interests are represented in their formation.

Important Considerations for Future Standards

Because technology is controlling more and more critical functions, it is important that it functions safely and reliably.  This is especially this case for technologies like autonomous vehicles, and medical devices.  The ability of devices to not interfere with each other and coexist operationally is of increasing concern.  Standards must be created and evolve to rapidly developing technologies and airways that are becoming busier with wireless communication.

The Importance of U.S. Involvement

Making tech standard development open to U.S. tech firms allows major technology developers to shape the industry based on expectations of future product capabilities.  U.S. product standards are often accepted as a baseline for the creation of international standards. 

Department of Commerce Secretary Wilbur Ross stated “The United States will not cede leadership in global innovation. This action recognizes the importance of harnessing American ingenuity to advance and protect our economic and national security.  The Department is committed to protecting U.S. national security and foreign policy interests by encouraging U.S. industry to fully engage and advocate for U.S. technologies to become international standards.”

Reasons for Concern

Huawei, a Chinese technology company, has been at legal loggerheads with the United States.  It has also been very active in the development of various international standards.  This action is meant to ensure Huawei’s placement on the Entity List in May 2019 does not prevent American companies from contributing to standards that will shape the future of important technology.

CVG Strategy

CVG Strategy offers consultant services for export compliance and ITAR.  We also offer a variety of services for product test and evaluation to commercial and defense standards.  We have expertise in environmental and EMI/EMC standards provide product test program management to assist your product development program during the Covid-19 pandemic.  Contact us today to see how we can help.

Product Test Management Services Help During Pandemic

Product Test Management Services
Product Test Management Services

CVG Strategy Offers Product Test Management Services

Product Test Management Services can assist in keeping product development schedules on track during the Covid-19 pandemic.  Many product developers are already behind schedule due to lock downs.  Sending engineering staff on travels to laboratory may not be a desirable option at this time.  CVG Strategy can help by providing a number of services to ensure that your product test and evaluation are performed properly. 

Solutions for Product Testing

The CVG Strategy test and evaluation team have decades of experience in product test management.  We can provide everything from defining test requirements to creating final test report summaries.  We have expertise in climatic, dynamic, ingress, product safety, EMI/EMC, and electrical test methods.  Services we provide include:

  • Test Standard Research
  • Life Cycle Environmental Profile for Reliability Analysis
  • Susceptibility Analysis
  • Test Requirement Analysis
  • Design of Required Simulation and Monitoring Equipment
  • Vibration Test Fixture Design
  • Test Plan Development
  • Test Scheduling
  • On Site Test Witnessing
  • Subject Matter Expertise for Pre and Post Test Evaluation

Third Party Advocate for Your Product

Product Test Laboratories, by definition, are limited in their ability to act as an advocate for your product.  Additionally, because of their customer load, they are unable to provide in depth attention to details such as product modes of operation.  Testing is complicated, expensive, and important for product verification and validation.  Attention to details can catch intermittent susceptibilities and vulnerabilities that can lead to product recalls and liabilities.  They can also prevent under or over test conditions that would invalidate test results. 

The collection of pertinent data is very important in testing.  It is essential for post test analysis of failures.  It is also necessary for test replication where sensor placements and device under test set up are critical.  CVG Strategy can provide through all of its services an attention to detail that is borne out of experience in hundreds of test programs.

Sectors of Product Test Management Service Experience

CVG Strategy has experience in the test and evaluation of many product sectors.  These include:

  • Defense
  • Commercial
  • Automotive
  • Aerospace
  • Ingress Protection
  • HALT and HASS

We can provide Subject Matter Expertise to assist in design analysis and troubleshooting for these sectors that can prevent recurrent test failures.

See How We Can Help

Contact Us today to see how we can help keep your product development on schedule.  We also offer EZ-Test Plan Templates for a number of test standards. 

 

Continuous Improvement and Organizational Development

Continuous Improvement and Organizational Development
Continuous Improvement and Organizational Development

What is Continuous Improvement?

Continuous Improvement and Organizational Development are valuable tools in a Quality Management System (QMS).  For improvement to occur it is essential that each important process in an organization be identified and analyzed.  Once identified and documented, these processes can be regularly reviewed to access effectiveness by applying improvement based on metrics.  It is important to realize that everything that happens in a business is a process and should be evaluated for inclusion into a QMS.  This is because there are no activities that can not be made more effective.  The benefits of this effectiveness can include increased product quality, enhanced customer satisfaction, reduction of costs, and employee satisfaction.

Types of Continuous Improvement

Basically there are two types of continuous improvement, incremental and breakthrough.  It all boils down to the size of the steps. Big steps can be more costly and involve a greater risk.  Therefore they are often reserved for cases where radical change is required.  Incremental improvement is taken in small steps an can be easily assessed for effectiveness.  Thereby allowing for more immediate adjustment of changes.

Establishing Paths for Feedback

Organizational feedback is very similar to feedback in mechanical systems.  The famous Scottish inventor James Watt pioneered early feedback mechanisms in the 1700’s.  One of his most important inventions was the centrifugal governor.  This mechanism automatically regulated the speed of a steam engine by supplying continuous feedback to a controller.  This mechanism paved the way for industrial automation and increased safety by removing the need for human intervention in a continuous process.

In a business setting, every stakeholder in a process is a source of feedback.  For effective use of the feedback all pertinent information must be assessed.  It must then be filtered in such a way as to remove statistical noise and then intelligently applied to inputs.  When applied, outputs can (results) be monitored as feedback to supply a control system into the process to provide continuous improvement.

Statue of James Watt, engineer and inventor, 1736 – 1819

Using Metrics as Feedback

Businesses today exist in a metrics rich environment.  A wealth of data is available for sales, costs, defective product, customer satisfaction, and employee process suggestions.  Looking into all data available in a process on a regular basis can provide more granular and intelligent findings.  These findings can be used to identify trends and point out potential issues before they become critical.  This is important because variances in business performance can occur for any number of reasons.  Understanding how all processes are effected by change can provide dynamic responses for continuous improvement and provide a smoother overall performance.

CVG Strategy

CVG Strategy quality experts understand continuous improvement and organizational development and how to set up management systems that can provide vital feedback as a business changes through all phases of development.   Contact Us with your questions to see how we can help.

Accelerometers and Laboratory Testing

Accelerometers and Laboratory Testing
Accelerometers and Laboratory Testing

What Test Witnesses Need to Know About Accelerometers and Laboratory Testing

Shock and Vibration analysis utilizing accelerometers and laboratory testing is a requirement for many commercial and defense standards.  Because accelerometers provide the feedback to the excitation system, proper selection and placement is essential.  To achieve optimal testing validity the test witness and test manager should have some knowledge about accelerometers and how they are used so as to provide valuable information to the laboratory personnel setting up the test.

Pre-test Preparation for Dynamic Testing

Having a fixture that is designed for your test item is optimal.  Having the same fixture to mount your test item on ensures that a test is repeatable.  This fixture should be characterized prior to testing so that no resonances or nulls to the shock or vibration profile are being introduced to the Unit Under Test (UUT).  Fasteners used should be characteristic of those to be used in the product’s intended installation and should be tightened to the specified torque.  Furthermore the UUT should be mounted on the fixture identically for all tests.

Know the Parameters of the Tests

Because of the wide range of possibilities, it is important that the test witness be aware of the characteristics of the profiles to be used in a dynamic tests.  These characteristics include the frequency range and the amplitudes.  It is a good idea to review this information from the test plan with the laboratory test engineer to ensure proper accelerometer selection.  Selection of an appropriate accelerometer is essential because of the wide variety of usable frequency range and amplitude scale.

Mounting of the Accelerometers

The method of mounting an accelerometer can greatly effect its frequency response.  Methods for mounting include stud mounting, adhesive, and adhesive mounting pad. 

When practical stud mounting provides the maximal frequency response.  Often a coupling fluid such as grease or beeswax is used to enhance frequency response to compensate for surface flatness or roughness.  If these are used the specific medium used should be documented so that the test parameters can be replicated. 

There are small differences between adhesives in their frequency responses.  Often Loctite 454 is used.  Generally these work well.  For testing where large forces are at play however, such as hammer shock tests used in shipboard shock and ballistic shock, adhesives are not advised.  These adhesives can fail during the test resulting in necessary retest and possible over test of the UUT.

Once the location of the accelerometer(s) have been established and validated the locations and means of mounting should be documented.  Documentation, preferably by photo, should also show the means of securing the accelerometer wiring because base strains caused by wiring can effect the response of the sensor.

Other Considerations

The vast majority of test laboratory engineers are well informed about the dynamic testing they perform on a regular basis.  They however, need to know about any specific information particular to the UUT.  If dynamic testing is to be conducted with the UUT in an operational state, areas that reach high temperatures should be noted.  If these areas are used for mounting the test engineer may have to utilize thermal compensation.  Additionally if the UUT generates extreme magnetic fields shielding might be required.

CVG Stategy Test and Evaluation Experts

CVG Strategy has performed test and evaluation for a wide range of commercial and military applications.  We have extensive experience in dynamic, climatic, and EMI/EMC.  We can provide test program management, test witnessing, test program documentation, and product evaluation.  Contact us to see how we can help you get the most from your test and evaluation program.

Effective Test Program Management for Better Products

effective product test management
effective product test management

Effective Test Program Management Requires Planning

Effective Test Program Management can add value to product development when its true value has been identified.  Too often product testing is left to the last moment, calls are made to test laboratories to ask what testing is required.  Equipment and somebody from the engineering team is transported off to a test lab and money and time is spent.  Hopefully testing is “passed” and requirements have been met to sell the product, but what has really been accomplished?

The Role of the Test Lab

Test Laboratories offer valuable services.  As such, finding a lab that can fill your requirements, provide flexible scheduling, and help keep the project in budget is important.  Maintaining good working relationships with those facilities is important.

The role of the lab, however, is by definition limited.  As an accredited third party evaluator they cannot act as an advocate for your product.  They can recommend a test matrix or provide a minimum criteria for product certification but ultimate responsibility for what testing is done lays with the test program manager.  Recommendations for testing should be reviewed in detail however as in many instances unnecessary testing may be performed. 

The Role of the Test Program Manager

Assessing Test Requirements

Developing a thorough understanding of relevant standards and compliance requirements is the responsibility of the test program manager.  Understanding the procedures to be performed will allow for proper scheduling.  It will also help in the development of appropriate fixtures, simulation equipment, and monitoring equipment.

Looking Beyond Compliance

Because product liability is becoming an increasing issue, product testing must consider testing beyond compliance requirements.  Performing a Life Cycle Environmental Profile and/or Susceptibility Analysis can be valuable in identifying product vulnerabilities.  A test matrix can then be created that includes appropriate evaluation methodologies to verify a design’s safety and ability to maintain customer satisfaction.

Test Program Documentation

Test Labs are beset with requests to perform testing without sufficient documentation.  While many types of testing are not tailorable, most standards still require documentation that provides descriptions of operational modes, power requirements, emergency shutdown procedures, and definitions of normal operation.  This documentation allows test lab personnel to make evaluations based on pass/fail criteria specific to the equipment being tested.  For those test methodologies that do require tailoring such as MIL-STD-810 or EN 61326-1:2013 test plans must be developed that specify procedures, severities, and appropriate data collection.

Hardware for Testing

Time must be taken to design and construct the equipment needed for test.  This equipment may include:

  • Vibration Fixtures
  • Extension Cables
  • Simulation Equipment
  • Stimulation Equipment
  • Monitoring Equipment
  • Dummy Loads

Care should be taken to consider test lab chamber and facility limitations when designing this equipment.  Simulation, stimulation, and monitoring equipment are extremely important in capturing intermittent failures.  This equipment is also required for pretest, during test, and post test functional and operational checks. 

Many people will have the test lab provide a vibration fixture.  Test lab fixtures are often in a constant state of modification as customers drill holes for their tests.  This means that even if the same piece of hardware is available at subsequent tests it will not be the same as when used before.  This may degrade the ability to accurately recreate previous testing.  Therefore it is considered a best practice to have a custom fixture.

Test Witnessing

Effective test program management requires active test witnessing.  Care must be taken to ensure that testing is performed as prescribed in the test plan.  Proper set up and pre-test operational testing should confirm that the equipment under test is working and functional.  Test witnesses can often assist lab personnel by monitoring equipment and confirming the status of the equipment.  Test witnesses should also collect data over and beyond that required by the lab so that test can accurately be reproduced.  Should any failure of test be encountered, the test witness should gather all data relevant for later analysis.  The witness should also, when appropriate, troubleshoot and determine root causes for failures.

Documentation

Documentation of testing should be created from test witness gathered data and test lab reports into a summary document that provides an overview that can be used to show due diligence and act as a guide for future product development in term of “lessons learned.  Any certifications or right to mark with regard to compliance testing should be noted as well.

CVG Strategy

CVG Strategy’s Test and Evaluation experts offer Test Program Management and Witnessing to assist you in getting real value from your testing program.  Contact Us to see how we can put decades of experience in commercial and defense testing to work for you.  Our experience includes climatic, dynamic, and EMI/EMC.

MIL STD 810H Humidity Method 507.6, A Deeper Look

MIL STD 810H Humidity
MIL STD 810H Humidity

MIL STD 810H Humidity

MIL STD 810H Humidity Method 507.6 is a test method for evaluating products that are likely to be stored and/or operated in a warm, humid environment.  MIL-STD-810 Environmental Engineering Considerations and Laboratory Tests is a Department of Defense (DoD) standard for military and commercial applications.  It is a series of laboratory test method that replicate the effects of environments on products.  These methods are meant to be tailored to the specific environmental effects expected during the life cycle of the product.  This is an important consideration because there are few definable goal posts in this standard.  Tailoring is required because the environmental effects likely to be encountered on equipment designed for aircraft, for example, will be quite different from those found on a vehicle.

Effects of Humidity

The effects of humidity are often overlooked when faced with more obvious environmental stressors such as temperature, shock, and vibration, but there are numerous physical and chemical effects that humidity can take place both within and on the exterior of equipment.  For surface effects; oxidation, electrochemical breakdown of coatings, interaction with deposits of materials that produce corrosive films, and changes in friction coefficients.  Other effects include; loss of physical strength of materials, degradation of insulative properties, changes in elasticity or plasticity, and degradation of lubricants.

Humidity Testing

Humidity is an extremely complex environmental phenomena that is intricately linked with temperature.  There a limitations in what a laboratory method can reproduce and simulate.  Method 507.6 is comprised of two procedures.

  1. Induced (Storage and Transit) and Natural Cycles
  2. Aggravated

For procedure I, induced cycles of temperature and humidity are used to simulate various storage and transit scenarios where equipment is packaged or stored in environmentally uncontrolled warehouses.  The standard points out that multiple tests may be applicable for storage or transit based on the nature of those sequences and nature of packaging.  Natural cycles are intended for the testing of equipment in its intended environmental conditions.

Procedure II exposes the test item to more extreme temperature and humidity levels than those found in nature, but for shorter durations.  While this can be an advantage for early detection of design vulnerabilities, results may not accurately represent those found in nature.

Climatic Considerations

Conditions of humidity vary considerably across the globe.  MIL-HDBK-310 defines three geographical categories that are used for generation of cyclic profiles.

B1 – Constant High Humidity

This profile is representative of conditions found in heavily forested areas with little solar radiation exposure.  Geographical locations typical of this profile are Congo and Amazon Basins, the jungles of Central America, Southeast Asia (including the East Indies), the north and east coasts of Australia, the east coast of Madagascar, and the Caribbean Islands.

B2 – Cyclic High Humidity

B2 profile occurs in the same areas as B1 but is more representative of urban areas where solar radiation exposure is expected.  Solar radiation when present in the diurnal cycle creates a wider variance in temperature and humidity.

B3 – Hot-Humid

This profile is found in areas near bodies of water with high surface temperatures, specifically the Persian Gulf and Red Sea.  Testing for this extreme condition does not verify the unit under test’s ability to endure the rigors of B1 or B2.

Additional Categories

Additional categories are provided for induced environments where temperatures as high as 160 °F (66 °C) can be reached for enclosed environmental conditions where little or no cooling air is available.  These induced categories are meant to replicate various transport and storage scenarios.

Test Duration

The effects of humidity require lengthy test durations to evaluate potential degradation.  Often testing is not performed at adequate lengths to provide meaningful data.  MIL STD 810H Humidity Method 507.6 durations are shown in the table below.

Hazardous Items

MIL-STD-810 states that hazardous test items will generally require longer tests than other items to achieve a desired confidence.  The standard defines Hazardous test items as “those in which any unknown physical deterioration sustained during testing could ultimately result in damage to materiel or injury or death to personnel when the test item is used”.  It calls for double the number of cycles for hazardous items. 

Non-Hazardous Items

For Natural Cycles, generally intended for operational testing, Method 507.6 calls for 15 to 45 tewnty-four hour cycles of testing dependent on which geographical area the equipment may be used in.

Aggravated Cycles

For Aggravated testing per Procedure II, ten cycles are recommended in addition to a 24 hour conditioning period.  Again the proviso for lengthening for hazardous items is called out but no exact measure is indicated. 

MIL-STD-810 H Table 507.6 II Test Cycles (days)

The Conundrum

For humidity testing there is often more questions than answers.  Today’s defense and commercial equipment is liable to be used anywhere in the world.  Given that time and money are major concerns for most product developers, it is unlikely that resources are available for testing all climatic categories for transit, storage, and operational profiles.  While Aggravated testing is tempting due to its shortened test length it may not provide realistic findings.  Unless product specifications specify exact testing requirements difficult decisions must be made. 

CVG Strategy

CVG Strategy’s test and evaluation experts have decades of experience in environmental (climatic and dynamic) testing as well as EMI/EMC.  We offer a wide variety of services including: EZ-Test Plan Templates, Test Program Management, Test Program Witnessing, and Product Evaluation.  We also provide a two day seminar/webinar “Understanding MIL-STD-810” to help your product development team garner the most from their test and evaluation programs. Contact Us today to see how we can help.

Electromagnetic Pulse Vulnerabilities and Product Design

Electromagnetic Pulse Vulnerabilities
Electromagnetic Pulse Vulnerabilities

What is an Electromagnetic Pulse?

Electronic products have Electromagnetic Pulse Vulnerabilities that could cripple infrastructure systems across the planet.  It is a serious concern that a number of agencies have reported on at length.   The Critical National Infrastructure Commission report of 2008 is one such example that outlines some dire possibilities.

Electromagnetic Pulses (EMP) can be both natural and man made.  Naturally occurring, these transient electromagnetic disturbances can be caused by lightning strikes, meteor explosion in earth’s atmosphere, or Coronal Mass Ejections (CME) caused by solar flares.  Man made disturbances include High Altitude Electromagnetic Pulses (HEMP) created by a nuclear explosions as high as thirty km above sea level and a variety of smaller weapons designed to disable pinpoint targets.

EMP events have a wide frequency range from DC to 1 GHz that have a duration of several nanoseconds.  This results in electric fields in thousands of Volts that can induce extremely high currents into electrical and electronic systems resulting in damage or complete destruction.  For those events caused by nuclear explosion, a second low frequency current caused by the disruption of the Earths magnetic field can cause major damage to power distribution systems.

Designing for EMP

A number of steps can be taken at the design stage for equipment that is considered safety critical.  These include screening, filtering of all power and I/O leads, and inclusion of voltage limiting components into a circuit.  Once a design has been implemented a variety of test methodologies are available for design evaluation.  While most of these involve military standard developers of products for commercial applications are often not restricted from their usage.  For example MIL-STD-461 RS105 is a standard used for shipboard equipment above and below deck to verify equipment’s ability to withstand transient electromagnetic field events. 

Consideration of inclusion of such testing into a test program should be taken for equipment that is critical to infrastructure requirements.  These types of equipment could include:

  • Electric Power
  • Telecommunications
  • Financial Service Industry Information Systems
  • Petroleum and Natural Gas Infrastucture
  • Transportation Infrastructure
  • Water Infrastructure
  • Food Infrastructure
  • Emergency and Health Services

CVG Strategy

CVG Strategy EMI/EMC consultants can perform a Susceptibility Analysis to identify Electromagnetic Pulse Vulnerabilities and provide design modifications to create products that can endure EMPs.  We can also recommend appropriate test and evaluation methodologies to verify these designs.  Contact us today to see how we can help.

EMI and Device Coexistence in Today’s RF Environment

emi and device coexistance
emi and device coexistance

The Growth of RF Spectrum Usage, EMI and Device Coexistance

Increased reliance on radio frequency communication has created issues for Electromagnetic Interference (EMI) and Device Coexistence.  Cellular devices and equipment using the Internet of Things (IoT) are major causes of this increase.  This has effected product development strategies for both commercial and defense applications, particularly for safety critical devices where unexpected operation or complete failure is not an option.

Product Design Considerations

Understanding the possible RF environments a product will operate in is essential during the specification phases.  Often conducting a thorough Susceptibility Analysis is required to develop an understanding of the variety of sources that could compromise a products performance and their probable signal strengths.  Equipment that can be expected to operate in radio rich environments such as airports can be expected to encounter high internet usage as well as radar and radio communications. 

For communication devices the crowded electromagnetic spectrum is it making more difficult to ensure reliable connections.  As an example the Department of Defense (DoD) is working to design a communication system known as the Wideband Adaptive RF Protection Program to develop adaptive filters to prevent signal cancelling.  For other such devices establishing minimum desired levels of reliability and developing protocols for re-transmission can be a solution.

Techniques for Evaluation

Susceptibility

For EMI/EMC susceptibility a number of standards are in place that can prove sufficient in assessing equipment’s abilities to operate as specified in a busy RF spectrum.  Often these tests are not requirements for categories of equipment compliance, so a product developer must be proactive in seeking these methods out.  Once an appropriate method has been found signal strengths and dwell times can be modified to achieve the desired level of product verification that replicates the anticipated environment of operation.

Wireless Coexistence

For wireless coexistence there are fewer options.  One possibility is ANSI C63.27-2017 “American National Standard for Evaluation of Wireless Coexistence”.  Although its primary application is medical equipment it can be used for any wireless application.  This testing can be used to:

  1. Develop user guidance necessary to achieve a desired level of reliable operation. In this case the deliverables can be guidance to the user on the maximum recommended operational distance between communicating devices and the minimum recommended separation distances to equipment that has the potential to cause loss of FWP due to interference.
  2. Determine the potential for successful operation of the Functional Wireless Performance (FWP) with regard to coexistence. The deliverables for this purpose can be a risk assessment, written with the intention that it be a part of a larger and more extensive total risk assessment for the product.
  3. Estimate the user experience. When the purpose is to predict the user experience, the test results are applied to the understanding of the intended operating environment to estimate the user experience in the intended operating environments. In estimating user experience, additional factors, beyond those included in testing, are involved. The resulting estimation has an evaluation uncertainty, which includes the Measurement Uncertainty (MU) of the test results, the estimation of the variability in the operating environment, and the certainty of the operating environment data used in preparing the estimate.
  4. Diagnose complaints and failure reports, reproduce those field environments, and qualify modifications that remediate the product performance. With this objective, the deliverables will include evidence that the problematic field environment has been reproduced and that test modifications can be expected to achieve desired levels of performance.
  5. Identify the intended environment parameters at which the EUT fails to coexist.

CVG Strategy Can Help With EMI and Device Coexistance

CVG Strategy EMI/EMC consultants can provide susceptibility analysis and recommend appropriate test methodologies for verification a product’s ability to perform as specified in today’s congested spectrum.  Contact us today to see how we can help. 

 

Product Packaging Evaluation for Durability

product packaging evaluation
product packaging evaluation

The Need for Adequate Product Packaging Evaluation

Product packaging evaluation is essential for a product’s success.  Excellent design and proper manufacture mean little if the product delivered to the customer is damaged.  Assessing packaging requirements requires an understanding of the product to be shipped fragility and a knowledge of the nature of transportation and storage scenarios likely to be encountered during transportation.

Environmental Stressors During Transportation

There are numerous stresses a packaged product will face during transportation and storage.  These stresses include dynamic forces such as shock, vibration, and drop.  They also include climatic conditions such as heat, cold, and humidity.  Additionally, for electronic products, electrostatic discharge, especially during handling can lead to complete malfunction or product degradation. 

Early evaluation should identify all possible modes of transportation and locations of storage.  These identifications should include realistic assessments of the duration of each step so that valid criteria of stress severities can be collected.  Once collected, perspective packaging methods can be chosen.

The Changing Nature of Packaging

With a marketplace more reliant on online sales, cardboard is becoming increasingly in demand.  Worldwide production of cardboard is increasing to meet this demand and prices for cardboard packaging is increasing.  As consumers and OEMs strive towards more environmentally sustainable behaviors, it is predicted that the overall use of plastics in packaging will decrease, placing further demands on the cardboard industry.

Cardboard while an excellent choice for many packaging needs has vulnerabilities.  These issues include crushing, piercing, water resistance, compression during stacking, and failure when overloaded.

Test and Evaluation of Packaged Products

There are numerous methods for the evaluation of packaged products including ASTM, Technical Association of the Pulp and Paper Industry (TAPPI), and ISO.  Many proprietary methods are required of vendors by their customers as is the case in the automotive sector.  These methods, once performed, can provide a reasonable assurance that a packaged product can reach its destination in good shape, ensuring customer satisfaction. 

As mentioned before, storage during and after the transportation phase should be taken into consideration.  Storage can often occur in uncontrolled environments that subject the package and product to induced environmental stresses.  Temperatures can be reached that greatly exceed those in the outside environment such as a warehouse without HVAC in hot climates.

CVG Strategy

CVG Strategy can assist product packaging evaluation.  We can provide a provide analysis of transportation and storage requirements and recommend appropriate test methodologies for verification and validation of packaging.  We can also provide test witnessing and test program management for a wide array of product sectors.

Medical Equipment EMC Susceptibility

Medical Equipment EMC Susceptibility
Medical Equipment EMC Susceptibility

Medical Equipment EMC and Electrical Susceptibility Issues

Incidents of medical equipment EMC susceptibility failures highlight the necessity of adequately accessing the electrical and electromagnetic environment of modern medical facilities.  Many of these were featured in the January 2020 IN Compliance Banana Peels column.  While the need for reliable operation of medical equipment is obvious, this requirement is shared by many types of equipment that involve critical safety concerns.  Often product developers depend on compliance requirements for verification of their products capabilities, but this should approach should not encompass the entire product assessment process for safety critical devices.

Understanding Possible Causes of Failures

Electromagnetic Interference (EMI)

EMI can damage electronic circuits or cause intermittent functional anomalies. EMI can be generated by environmental factors. Sources of naturally occurring EMI include:
• Radio Atmospheric – (Sferic) Broadband impulses that occur as a result of lightning.
• Solar Radiations – Including Solar Flares and Aurora Borealis resulting when charged particles emanating from the sun interact with Earth’s magnetic field.
• Cosmic Noise – Radiation caused by planets and other stars other than the sun. (Generally, this does not pose a significant risk to modern electronics.)

EMI can also be caused by other electrical and electronic systems in the proximity of a device.  Potential sources of interference include any number of analog or digital sources including the intentional jamming of Wi-Fi devices.

EMI can be classified into broadband and narrowband. Broadband EMI is usually from unintentional radiators. Sources of broadband include power convertors, electrical motors, and digital circuits. Narrowband is usually generated by intentional transmitters. These include TV and radios stations, cellular phones, Wi-Fi and Bluetooth devices.  EMI can enter a circuit either by radiated energy or energy coupled onto wiring such as power inputs. These energies are further categorized into radio and magnetic. Magnetic refers to low frequencies generally below 100 kHz. Radio extends from 100 kHz to the GHz range.

Electromagnetic Compatibility (EMC)

Electronic products are potential sources of energy that could interfere with the normal operation of electronic devices in the vicinity. This energy may be transmitted both in radiated and conducted forms.  Radiated may be comprised of digital signals generated by the circuitry, energy generated by Point of Load (PoL) voltage regulators, or inappropriate usage of intentionally radiated Bluetooth or Wi-Fi signals (e.g. transmission protocol or excessive bandwidth).
Conducted energy could be introduced onto power or interconnecting cables.

Electrical Compatibility

Disruptions to the power supply network can result in intermittent malfunction or damage to electronic products.  These effects can be generated by inductive loads such as electrical motors when turned on and off. They can also be caused by lightning strikes or power grid momentary failures.

Electrostatic Discharge (ESD)

ESD can damage circuitry. ESD failures are caused by the rapid transfer of charge (current) and the short duration, high-energy radiated electromagnetic fields generated during the ESD event. The effects of these failures may be immediate or latent (delayed), with the failure mode ranging from a temporary deviation in the subsystem’s specified performance to damage requiring repair or replacement of the device.  Electronic systems and components are susceptible to ESD exposure during manufacturing, packaging, transportation, handling, and installation phases of their life cycle. These discharges can occur in any area but are of highest probability in hot dry climates.  Discharges often occur as a result of human contact. These discharges can be in excess of 10,000 Volts.

Understanding the Product’s Intended Environment

For any product, understanding the aforementioned causes of susceptibility as they relate to the intended environment of usage is of great importance.  A modern medical facility is packed full of electronic devices that are radiating energy and causing electrical supply fluctuations.  Medical facilities also have a high density of people that can create ESD events.  These same people are also using wireless devices that can cause susceptibility and communication issues for safety critical devices.

For other safety critical products intended environments may include locations such as industrial facilities where electrical disturbances due to switching of highly inductive and capacitive loads are likely to be present. These industrial environments may also have highly radiative and conductive potential for interference due to the usage of heavy machinery emissions.

This critical analysis of a products intended environments including manufacture, transportation, installation, and usage can provide a susceptibility assessment and analysis.  This susceptibility assessment and analysis can identify potential causes of susceptibility, provide risk assessment, and lead to a test matrix that will provide essential design verification of a product.

CVG Strategy Expertise

CVG Strategy EMI/EMC consultants can provide susceptibility analysis and recommend appropriate test methodologies to ensure reliable operation of safety critical products.  Our team has decades of experience in automotive commercial, aerospace, and defense sector testing. We can also provide assessment for coexistence of products using Wi-Fi protocols.

Product Compliance Testing and Beyond

product compliance testing
product compliance testing

Product Compliance Testing

Product compliance testing is a requirement for bringing products to market.  These tests vary dependent on which global market sectors are being targeted.  Requirements differ from product type to product type and standards are constantly being created and revised.  It requires a great deal of effort to stay current on what testing will be required, and as always it is an expense and can delay a product development program.

Product compliance standards deal with a number of issues concerning product safety, meeting customer requirements, electromagnetic compatibility (EMC), and product ruggedness.  While these standard generally provide for qualification of a products quality and safety they can not be a guarantee that a product will meet all expectations.

Product Safety Concerns

As products become more sophisticated and capable they must be capable of consistent and reliable operation.  Failures can lead to property damage, injury, and even death.  It is no secret that product liability is a rapidly growing field in the legal profession.  Aside from legal concerns customer satisfaction and company reputation are at stake.  A brief glimpse of the news can provide ample evidence of the importance of getting product development right before product release.

EMI/EMC testing is playing a more vital role in product safety testing as dependence on electronics increases susceptibility issues.  Many test standards have less than adequate susceptibility requirements.  It is therefore critical that adequate consideration be given to the possible effects of a susceptibility issue on a product’s safety and the need for evaluation over and above that called out for in product compliance testing.

Product Quality and Sustainability

Consumers are showing an increased demand for products that support sustainability.  We are gradually moving beyond acceptance of products that must be replaced early in their life cycle.  If manufactures wish to capitalize on this trend, then developing and marketing products that can meet the rigors of a longer life span will demand thorough evaluation.  This requires an assessment of climatic and dynamic stressors likely to be encountered during a products life cycle and selection of test methodologies to evaluate their effects. 

CVG Strategy Test and Evaluation Experts

CVG Strategy offers a wide array of services to assist product developers in product compliance testing.  We also provide consulting services that can provide product evaluation to identify potential vulnerabilities and develop recommended test methods to ensure a quality product.  Our experts have decades of experience in commercial and defense product test and evaluation. 

Product Ruggedness and Water Centered Test Methods

product ruggedness and water
product ruggedness and water

Water is a Major Concern in Product Ruggedness Testing

Water is part of many test methods when evaluating product ruggedness. We live in a world that is predominated by the substance, and its effects on products for any application are severe. Because of this, products must be evaluated for their abilities to endure exposure to water as a solid, liquid, and as a gas. These tests, although seemingly simple, can present challenges to product designers.  Effects of water on products include:

  • Possible degradation of strength
  • Corrosion or erosion of materials
  • Fungal Growth
  • Malfunction of electronic and electrical equipment with possibility of hazardous operation
  • Fouling of lubricants
  • Increased chemical reactions
  • Swelling of materials
  • Condensation
  • Changes in material properties such as elasticity

Ingress Testing

Ingress testing is found in a wide variety of industry specific test methods.   Perhaps the standard with the broadest use is IEC 60529 which evaluates a product’s degree of protection as classified by an Ingress Protection Code (IP Code).  These tests also involve solid foreign objects including dust.  Testing that involves water includes dripping, spraying, splashing, jetting, powerful jetting, temporary immersion, continuous immersion, and water jet with high pressure and temperature. 

Similar testing can be found in standards specific to the aerospace, automotive, and military sectors.  In the automotive sector a number of ISO, IEC, and proprietary standards are used in evaluation.  In defense applications MIL-STD-810 includes testing for blowing rain, immersion and fording.

Of major concern in these tests are gaskets and seals used to create “waterproof” enclosures.  Though it may appear to be an easy task, gasket design can be a great challenge.  In many cases a gasket must not only protect against ingress but also serve to attenuate radio frequency energy to meet EMI requirements.  The sealing materials must also endure thermal, solar, and dynamic effects.  In some cases, such as wind blown rain, the impact of droplets can cause resonances that defeat otherwise sound barriers.

Humidity

Large portions of the planet experience intense humidity.  Some areas experience this year round.  Additionally certain applications such as marine will have extreme conditions.  Humidity can wreck havoc in a large number of ways.  It can degrade plastics.  It can interact with deposits of dust and other substances to produce corrosive films.  Testing for the effects of humidity is difficult.  Thorough evaluation usually involves lengthy tests that can last months.  Aggravated or accelerated testing can at times be useful to point out potential design deficiencies, but it can be difficult to ascertain the validity of data returned with respect to anticipated exposures.

Fungus

Exposure to airborne fungal mycotoxins can be highly hazardous to humans resulting in neurological damage and cancer.  Fungus and mold species prosper in humid conditions.  A number of test standards can evaluate a products potential for supporting fungal growth.  It can be difficult to ascertain this by a simple analysis of materials in a Bill of Materials because deposits of contaminates may find their way on to a product during manufacturing or actual use.  Generally these organisms can attack a wide variety of materials.  Additionally their metabolic wastes can degrade materials.

Salt

Airborne salt can cause extreme corrosion.  Salt fogs are common in coastal areas and of course in marine applications.  Testing of protective coatings is essential for products that can expect such exposure.  While test methods can detect possible sources of problems they are not effective simulations of the actual environmental effects.  Of further concern, testing is usually performed on new product.  How a protective coating performs after thermal and solar can be difficult to evaluate, as can the effects of dropping, or impacts sustained in actual use.

Water as a Solid

Product ruggedness can be greatly diminished by ice and frost.  Deposits of ice can cause structural failures and of course render devices inoperable.  Frost and ice can gradually cause failures of seals and gaskets.  It can also cause failure of bonding materials and cause distortion of parts when recurring icing and thawing events occur.  Test methods are available for evaluation of ice effects and time should be taken to select appropriate procedures based on a product’s intended usage.

CVG Strategy

CVG Strategy has extensive experience in product test and evaluation of product ruggedness and water.  We can evaluate products, examine requirements, assess gasketing and sealing methods, and develop a test matrix to ensure that a product will perform as designed for its intended service life.  We provide a variety of consultant services to assist in product testing.

Using MIL STD 810 in Product Development

using mil std 810
using mil std 810

When to Start Using MIL-STD-810

Most product designers begin using MIL STD 810 when they are ready to select test methodologies to evaluate a product, but to get the most from this standard it should be employed when first establishing design criteria and specifications.  Using the standard this way can save significant time and money in product development and help create a product that meets requirements and maintains customer satisfaction for the products lifetime.

Why Early?

Most test standards establish criteria for product specification in form of requirements, so in a sense all applicable test standards should be referenced when considering the creation of a product, but this is especially the case with MIL-STD-810.  Because this standard is much more than a collection of test methodologies with requisite requirements, it provides useful tools for analysis of environmental stresses likely to be encountered by the product from the time it leaves the shipping dock until it reaches its end of life.

This analysis, which examines logistical, tactical, and operational phases of product life provides a list of environmental stressors likely to be encountered by the product on its platform of intended use.  Further use of this guidance can provide appropriate profiles and severities based on the geographical areas of intended usage and the characteristics of the platform (ship, vehicle, aircraft) on which the product will be installed.

This analysis, along with measured data and customer requirements, will create a list of relevant and substantiated data from which specifications can be drawn.  This in turn will allow for a product that is neither over or under engineered.  It will also, of course, provide parameters for appropriate evaluation through testing.

A Standard With Three Parts

MIL-STD-810 is composed of three parts.  The first part describes the tailoring process which provides the aforementioned analysis.  Tailoring is a management and engineering procedure that conducts a Life Cycle Environmental Profile (LCEP) and creates an Environmental Issues/Criteria List (EICL).  The second part contains, as of Revision H, the 29 laboratory test methods for product evaluation.  The third part contains climatic data and guidance derived from a number of sources.

Given the complexity of modern environmental laboratory test methods, it is not surprising that parts 1 and 3 of the standard are often overlooked by designers, lab personnel, and even those involved with educating people about the standard.  A look through the many annexes in part 2 can be quite daunting.  Furthermore, many of these methods, especially dynamic (e.g. vibration and shock) are changing rapidly as the technologies utilized in the methods develop. 

Learning to Use MIL STD 810

CVG Strategy provides education in this important standard.  Our instructors have decades of experience in laboratory test and evaluation of military and commercial products.  We understand the importance of testing and getting a properly designed product to market in a timely fashion.  Instruction includes extensive coverage of the tailoring process and how to use it your product development.  Our courses are available online and on location. 

 

MIL STD 461 RE102 Radiated Emissions

MIL STD 461 RE102
MIL STD 461 RE102

MIL STD 461 RE102 Radiated Emissions Testing

MIL-STD-461 RE102 is a test method for evaluating electric field radiated emissions from systems and subsystems enclosures and cabling designed for U.S. military applications.  Requirements and testing vary for intended platform of intended installation.  The frequency ranges applicable for various platforms are:

  • Ground:  2 MHz to 18 GHz
  • Surface Ships: 10 kHz to 18 GHz
  • Submarines: 10 kHz to 18 GHz
  • Aircraft (Army and Navy): 10 kHz to 18 GHz
  • Aircraft (Air Force):  2 MHz to 18 GHz
  • Space:  10 kHz to 18 GHz

By the numbers, limits imposed on emissions are severe and well below most commercial standards.  The numbers however, do not tell the entire story, because test values measured are peak values, not average or quasi-peak.  Measurements are also made with antennas positioned 1 meter away from the edge of the test set up.  In short there is not an apple to apple comparison that can be made between RE102 and other standards; the emission limits are lower, the frequency ranges are larger, and the measurements are performed in a more severe manner.

Getting it Right

While RE102 testing should be performed as early in product development as possible, it is important that the test item be as representative as possible.  This means that enclosure, PCB revisions, firmware, software, and cabling should be fully representative of the final product.  Care should also be taken in creating the ability to simulate normal modes of operation so that testing can be performed on the Equipment Under Test (EUT) that reflects its intended use.  All of these parameters should be reflected in an Electromagnetic Test Procedure (EMITP) that is constructed in accordance to MIL-STD-461 requirements as described in DI-EMCS-80201.

Facing the Music About RE102

The simple fact is that most product developers do not pass MIL-STD-461 RE102 testing the first time.  Retest and redesign cost money and time.  Adding patchwork cures such as filtered connectors can add significantly to product cost and often not provide the required attenuation.  Often the most cost effective solution is to perform an evaluation of the product to assess sources of the emissions and make design changes to mitigate them before they can couple onto wiring and power sources. 

CVG Strategy Can Help

CVG Strategy offers a wide array of services to help you with EMI/EMC issues.  Our experts have extensive experience in MIL-STD-461 RE102 and many other military and commercial standards.