Our latest eBook, 2022 Rugged Interconnects for Harsh Environments, highlights how today’s connectivity solutions overcome the challenges of temperature, shock and vibration, radiation, corrosion, dust and water ingress, and difficult access. Experts from 18 leading connector suppliers address harsh environment connectivity through design, connector specification, performance factors, standards, materials, modification, and adaptation, for a variety of applications.
RUGGED INTERCONNECTS FOR HARSH ENVIRONMENTS EBOOK
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Harsh environments are found everywhere. Sensors, connectors, and relays must be able to withstand dirt, moisture, salt, and vibration endemic to all harsh environments. TE Connectivity delivers reliable products capable of withstanding a variety of harsh environments.
RUGGED INTERCONNECTS FOR HARSH ENVIRONMENTS EBOOK
Our latest eBook, 2022 Rugged Interconnects for Harsh Environments , highlights how today’s connectivity solutions overcome the challenges of temperature, shock and vibration, radiation, corrosion, dust and water ingress, and difficult access. Experts from 18 leading connector suppliers address harsh environment connectivity through design, connector specification, performance factors, standards, materials, modification, and adaptation, for a variety of applications. This eBook also features a Products Briefs selection of more than 30 innovative connectivity products designed to support connected systems across a range of application environments and markets. Contributors include Amphenol Communications Solutions, Amphenol LTW, Amphenol PCD , Axon’ Cable , Bernier, CDM Electronics , COAX Connectors , Fischer Connectors , Greene Tweed, Harwin, Hirose Electric, LEMO /Northwire, Omnetics Connector Corporation , Phoenix Contact , Smiths Interconnect, TE Connectivity , Times Microwave Systems , and WAGO . Please enjoy this edition, the second of three 2022 eBooks. Our next eBook, High Speed with Signal Integrity , will be available in August 2022. This collection will look at the ways connectivity solutions handle signal distortions due to impedance mismatch, crosstalk, attenuation, reflection, and switching, as well as any other issues and solutions related to high speed signal and data. In the meantime, please subscribe to our weekly e-newsletters, follow us on LinkedIn, Twitter, and Facebook, and check out our eBook archives for more applicable, expert-informed connectivity content.
Managing Editor Amy Goetzman
Associate Managing Editor
DESIGNING AND SPECIFYING INTERCONNECTS FOR HARSH ENVIRONMENTS
INTERCONNECT SOLUTIONS FOR MIL-AERO APPLICATIONS
HOW TO DETERMINE SUITABLE INTERCONNECT SOLUTIONS FOR HARSH ENVIRONMENT APPLICATIONS BERNIER
DESIGN PLANNING GUIDELINES AND CHECKLISTS ENSURE PERFORMANCE IN HARSH ENVIRONMENTS OMNETICS CONNECTOR CORPORATION
ROBUST FIBER OPTICS ARE FLYING HIGH IN SATELLITES AND LOW-ALTITUDE EVTOL AIRCRAFT TE CONNECTIVITY
STANDARDS, MATERIALS, AND TESTING FOR FOUR TYPES OF RESISTANCE FISCHER CONNECTORS
FIVE MILITARY TRENDS PAVING THE WAY FOR HARSH ENVIRONMENT CONNECTIVITY AMPHENOL PCD
TOP QUESTIONS TO ASK WHEN SELECTING CABLE FOR HARSH ENVIRONMENT APPLICATIONS LEMO/NORTHWIRE
CONNECTORS FOR SPECIFIC HARSH ENVIRONMENT APPLICATIONS
UNINTERRUPTED CONNECTIVITY SOLUTIONS FOR HARSH ENVIRONMENTS AMPHENOL LTW
HEAVY-DUTY CONNECTORS PROTECT THE FLOW OF POWER AND DATA IN ROBOTS IN HARSH INDUSTRIAL ENVIRONMENTS TE CONNECTIVITY 73 HARSH ENVIRONMENTS NO LONGER DERAIL RELIABILITY OF
UNRIVALLED PERFORMANCE IN CRITICAL ENVIRONMENTS SOLVES INTERCONNECT CHALLENGES SMITHS INTERCONNECT 30 HARSH ENVIRONMENTS REQUIRE MODIFICATIONS TO COMMON CONNECTORS AMPHENOL COMMUNICATIONS SOLUTIONS 36 INNOVATIVE INTERCONNECTIVITY SOLUTIONS FOR HARSH ENVIRONMENTS COAX CONNECTORS LTD 41 HOW TO ADAPT INTERCONNECTS TO HARSH ENVIRONMENTS AXON’ CABLE ADAPTING CONNECTORS FOR HARSH ENVIRONMENTS 46 IMPLEMENTING EFFECTIVE INTERCONNECTS INTO SPACE SYSTEM DESIGNS HARWIN INTERCONNECT SOLUTIONS FOR SPACE & OTHER REMOTE APPLICATIONS 50 CHOOSING CONNECTIVITY AND PACKAGING SOLUTIONS FOR REMOTE MONITORING IN HARSH ENVIRONMENTS PHOENIX CONTACT
RAILROAD CROSSINGS WAGO CORPORATION 76 A SHIFT IN POWERTRAIN CONNECTIVITY HIROSE ELECTRIC
80 HOW PAEK COMPARES TO GLASS-TO-METAL SEALED CONNECTORS GREENE TWEED 84 OVERMOLDED CABLE ASSEMBLIES FOR ADVANCED INTERCONNECT PERFORMANCE CDM ELECTRONICS CONNECTORS FOR SPECIFIC HARSH ENVIRONMENT APPLICATIONS
ONE SIZE DOES NOT FIT ALL: OPTIMIZED CONNECTORS ARE CRUCIAL TO SYSTEM PERFORMANCE TIMES MICROWAVE SYSTEMS
DESIGN PLANNING GUIDELINES AND CHECK LISTS INSURE PERFORMANCE IN HARSH ENVIRONMENTS BOB STANTON DIRECTOR OF TECHNOLOGY OMNETICS CONNECTOR CORPORATION
The range and expansion of electronic applications today has extended the need for analysis and preparation of circuit designs to survive new operating settings in extreme harsh environments. Navigation electronics that have been employed in automobiles for navigating our city streets are now playing a role in deep space exploration. As technologies move into new environments, diligent planning is required to ensure the design format and material selection for these advanced systems can endure the challenging conditions they will face. A wide range of connector and cable systems support the data acquisition, processing, and signal routing in these new circuits. Often, the connectors
and cable harnesses are exposed to the most extreme environmental conditions surrounding the application. Exterior sensors, camera systems, and extended arms or robotics often operate outside of the main equipment structure. The interconnects involved must be designed to withstand very rugged treatment.
connectivity in a very small format. MIL-DTL-32139 for Nano-D, nanominiature rectangular, connectors with pin-to-pin center spacing at .025” (0.635 mm) are another popular choice for small, lightweight connectivity. An overall guidance specification for higher reliability in harsh environments is listed as MIL-STD-790 and is updated by the U.S. Defense Labs as technologies evolve.
MILITARY RELIABILITY SPECIFICATIONS FOR MICRO-D AND NANO-D CONNECTORS
Omnetics Connector Corporation
Experienced interconnect designers can assist in the planning and building of electronic systems that can help ensure performance and longevity for the whole unit. Key planning steps should include a thorough awareness of the environmental dangers the products may encounter. This should include a review of NEMA environmental standards, including IP code 250, which covers hazardous and environmental exposure. Products that meet military standard specifications can provide additional reassurance. Highly portable, rugged, and reliable MIL-DTL-83513 Micro-D connectors are a very popular choice for harsh environment applications. Micro-D subminiature connectors with pin-to-pin center spacing at .050” (1.27 mm) provide powerful
High Speed Digital
Harsh environment connector designs depend on rugged materials, durable physical forms, and interfaces that can protect the connector pin to socket in the event of high shock and vibration and other environmental attacks. As circuit and sensor electronics evolve, they get smaller and operate faster on low voltages and currents. Micro and nano connectors are becoming the standard interface from cable to board or cable to instrument because they are lightweight and absorb high vibration and shock conditions. In many instances, the new equipment operating in extreme environments is detecting, collecting, and processing massive amounts of data without human involvement. These technologies are rapidly pushing beyond 10 Gb/s. To achieve these high speeds, digital signals are designed to operate at very short signal rise time. This is accomplished with higher-speed chip technologies such as GaAs and Gallium Nitride, which also operate at lower voltages. As a result, the short signal rise time and low-voltage signals flow on very short signal lengths at minimal heights. These new mini-digital signals must be carefully protected, both physically and electrically, from interference. For example, cable wiring is often designed to carry the positive and negative digital signals on separate wire pairs that run in parallel with their ground return wire. Each signal set is protected and wrapped in insulation and then shielded from outside electrical elements.
Digital cables used in extreme environments can be protected with polymer jackets that provide strain relief. This jacketing can survive heat cycles. With the addition of metal braided shielding, cables can be physically protected and shielded from electronic signal interference. In space-constrained applications that experience repetitive motion, the cable may need to be small in diameter yet also be strong, resilient, and flexible enough to accommodate constant bending and folding. For example, high-speed assembly robots are now performing many assembly tasks in the automotive industry. If the cable and connector are not designed properly, wear and tear on the interconnects can impact automated systems and shut down the assembly line.
Prior to connector and cable selection, designers should review potential exposure.
Review the application and potential harsh conditions using the checklist on the next page. THE COMPLETE DESIGN, MANUFACTURING, AND TESTING PROCESS
Shielded Micro-D and Nano-D from Omnetics
1. Begin work with a MIL-quality level interconnect company that has experience in similar applications and can offer design consulting. A company that can interactively
5. Have harsh environment testing performed by a test lab that has many years of experience with multiple test processes that replicate the extreme variables connectors face in harsh environments. A wide range of environmental testing should be done, including exposure to mixed flowing gas, humidity, temperature, salt fog, dust, and thermal cycling. Testing for shock and vibration using drum- like systems can mimic aircraft and drone vibrations. Testing components for corrosive reactions, moisture resistance, temperatures at altitude, and plating durability helps ensure the product will perform reliably in its expected operational setting.
use solid modeling can help tailor existing high- reliability designs to fit the device. 2. Review harsh-environmental requirements with the connector and cable supplier to ensure the appropriate cable, metals, plating, and polymers fit within the application. (For example, outgassing levels of epoxies must meet NASA specifications if the component is used in space applications.) 3. When the first solid models are ready, request delivery of a 3D prototype to insure both cable and connectors fit within the design. 4. When the final interconnect is approved for size, shape, materials, and construction, have multiple sets built up for harsh environment reliability testing.
RUGGEDIZED CIRCULAR CONNECTORS FROM OMNETICS A DESIGNER’S HARSH ENVIRONMENT CHECK LIST
Note: This is a sample of typical conditions. Each application may have additional issues.
Harsh connector planning and design is a well-worn path to achieving high reliability interconnection systems. Designers have multiple resources available to ensure products not only survive the rigors of extreme use but can improve their system performance. For assistance, designers can
review examples of connectors that have already passed these tests in existing harsh environment applications ranging from space and defense to medical applications.
Visit Omnetics Connector Corporation to learn more.
STANDARDS, MATERIALS, AND TESTING FOR FOUR TYPES OF RESISTANCE WIM VANHEERTUM, PRODUCT MANAGEMENT DIRECTOR, FISCHER CONNECTORS
To function both properly and durably, heavy-use and safety-critical applications and their interconnect system must be especially designed to withstand mechanical stress and environmental conditions without degrading power, signal, or data transmission. Ruggedization methods and processes apply to the entire design, engineering, and manufacturing cycle in the creation of high-performance connectivity solutions. From choosing high-quality materials for housing, coating, plating, insulating, and sealing to protecting the insulation and conductor core
against environmental challenges and chemical deterioration, material choices for connectors, and overmolding or jacketing for cables, helps maintain the integrity of the connection under extreme conditions. The table below shows key factors that should be considered to enhance ruggedness, ensure a device’s reliable operation, and increase product life cycles to achieve less downtime and longer maintenance intervals.
(References to KPIs, materials, testing methods, and industry standards mentioned in this article apply to products and solutions engineered by Fischer Connectors.)
Design engineers should consider four main types of resistance when working on interconnect solutions for extreme operating conditions: 1) vibration and shock, 2) extreme temperatures, 3) corrosion and chemicals, and 4) radiation.
VIBRATION AND SHOCK RESISTANCE
The ability to withstand dynamic stress exerted by vibration, drop, and impact is a key requirement for rugged interconnect solutions. These components must be able to perform, despite rough handling, transportation, and fluctuating conditions in the field. Extremely rugged connectivity solutions are tested in compliance with the MIL-STD-202-214 Random Vibration testing standard (Military Standard 202, Method 214 and Condition I), which determines the ability of component parts to withstand the dynamic stress exerted by random vibration applied between upper and lower frequency limits to simulate the vibration experienced in various service field environments. Mounted onto vibration testing equipment, the locking and contacts specifications (or functionalities) of a connector pair is thoroughly verified. Electrical signals are monitored to ensure that no micro-cuts smaller than one micro-second occur.
Monitoring of electrical signals ensures that interconnect solutions can withstand shocks of high G amplitude, in compliance with MIL-STD-202 Method 213 and EIA-364-27. Drop resistance tests measure the mechanical deformation that could impact the connection’s functioning and performance following drops or bump shocks from different heights. The most rugged connectors designed by Fischer Connectors, the Fischer UltiMate Series, can withstand random vibration of up to 37.80 Grms and shocks of up to 300 G amplitude (half sine pulse of 3 ms, no discontinuity > 1 μs).
conditions it will experience throughout its service life and establishing chamber test methods that replicate the effects of environments on the equipment rather than imitating the environments themselves. Although prepared specifically for military applications, the standard is often used for commercial products as well. Standardized connectivity products that operate within the temperature range of -55°C to +135°C are available. Cabled connectors overmolded with TPU material withstand temperatures ranging from -40°C to +125°C, whereas soft caps resist a temperature of +85°C. Tailored solutions can be designed to reach much higher or lower temperatures for dedicated applications. For example, IP68/69 sealed and hermetic chromium-plated brass connectors can resist chemicals and extreme temperatures ranging from -100°C to +200°C. The premium materials used in such connectors also allow them to withstand most sterilization methods used in medical applications, such as steam autoclaving per IEC 60601-1.
High-end solutions may be tested for compliance with the U.S. Military Standard 810, Methods 501.6 (high temperature) and 502.6 (low temperature). This standard emphasizes tailoring an equipment’s environmental design and test limits to the Data transmission must remain stable even when there are vibrations. ME-Meßsysteme’s six independent strain gauge sensors rely on the ultra-miniature, vibration- resistant Fischer MiniMax Series. EXTREME TEMPERATURE RESISTANCE
Sterile or aseptic connectors and cable assemblies must be appropriately sealed to withstand ingress from steam saturated with water under at least 15 psi of pressure during multiple autoclave sterilization cycles (up to 1,000 cycles) that usually last 30 minutes. The World Health Organization recommends that hospital instruments and all equipment in the hospital rooms should be saturated in an autoclave at 121°C (250°F) for 30 minutes or 134°C (273°F) for 13 minutes. Fischer Core Series Brass, Stainless Steel, and Plastic 405 connectors are sterilizable in autoclave, Cidex, EtO, gamma radiation, Steris, or Sterrad systems.
CORROSION AND CHEMICAL RESISTANCE Choosing the right materials and coating can protect connections against galvanic corrosion mechanisms – pitting, intergranular, or crevice. The most common coating on metallic parts is nickel chromium or thin gold-based layers applied with a galvanic or sputtering deposition process. Common materials and coatings used in circular connectors are: • Brass with nickel or chromium coating • Aluminum with nickel or chromium coating or anodized (aluminum oxide Al2O3) • Stainless steel, which is one of the best materials for corrosion resistance, since corrosion protection is embedded within the material itself. Products are tested in compliance with standards such as IEC 60068-2-11 Test Ka, MIL-STD-202 Method 101, and EIA-364-26. Testing includes long-standing exposure to a 5% salt solution at a temperature of 35°C to ensure that there is no impact on mechanical or electrical functionalities. In hospital, dentistry, and laboratory settings, as well as in food and pharmaceutical processing, devices and equipment must be regularly cleaned, disinfected, and sterilized. Product components – shells, contact blocks, O-rings and seals, cable jackets – should be made of ultra-resistant materials to withstand the conditions brought about by sterilization methods with chemicals such as Steris LCS (Liquid Chemical Sterilant with peracetic acid), Sterrad (hydrogen peroxide plasma), EtO (ethylene oxide), or through disinfection cycles such as Cidex Plus (glutaraldehyde) and Cidex OPA (ortho- phthalaldehyde and phosphate salts).
Chemical-proof connectivity is also demanded in the defense & security, and oil, gas, and petrochemical industries. In the latter hazardous environment, workers on land or offshore use downhole monitoring applications, seismic evaluation and drilling instruments, and geophysical and infrastructure maintenance devices that must resist chemicals such as aliphatic hydrocarbons, oils or fuels, greases, dilute acids and bases, detergents, and most aqueous salt solutions. For certain ATEX certified areas and equipment in the petrochemical industry, additional property requirements for cables include flame retardancy and fire resistance.
With their special surface finish, most of Fischer Connectors’ products can withstand exposure to salt fog for 1,000 hours. Tested in compliance with IEC 60512 and MIL-STD-202H / 810G / 883K standards, the ultra-rugged NATO STANAG 4695 compatible Fischer UltiMate 80 connector passed several mechanical and electrical tests after an immersion of one hour into cutting oil Swisscut Twin 300, isopropylic alcohol, and fractionated fuel 60/95. It also offers high corrosion resistance (500 hours of salt mist).
RADIATION RESISTANCE High radiation resistance is required for tasks in nuclear or contaminated environments such as handling heavy radioactive loads, performing inspections, and repairing equipment. These tasks are sometimes performed remotely with robots due to inaccessibility or the danger of radiation exposure. Radiation-resistant connectors and cables are also required when healthcare professionals sterilize medical devices and equipment using gamma irradiation (typically Cobalt 60).
such as plastics, that require low-temperature sterilization. Some single or two-piece shell disposable connectors with housing in ABS plastic withstand sterilization with both gamma irradiation per ISO 11137-2 (up to 60 kGy for Fischer Core Series Disposable) and EtO per ISO 11135. Suppliers of high-performance, radiation-resistant connectivity solutions are regularly audited by their customers to ensure that they are compliant with main nuclear safety standards such as KTA 1401 from the Nuclear Safety Standards Commission (Kerntechnischer Ausschuss, KTA) and IAEA 50-C-Q from the International Atomic Energy Agency (IAEA).
In hospital settings, there has been an increase in medical devices and instruments made of materials,
Fischer Core Series Stainless Steel connectors are made of 316L stainless steel, polyether ether ketone (PEEK), and ethylene propylene diene monomer (EPDM), offering high radiation and corrosion resistance while ensuring high performance even in high temperatures. They also allow microbiological sterilization and radioactive decontamination.
SELECTING MATERIALS FOR RUGGED CONNECTIVITY
The following table helps identify which type of material is the most suitable for use in shells, contact blocks, and O-rings and sealing.
Visit Fischer Connectors to learn more.
An aid to selecting the most suitable material for shells, contact blocks, and O-rings and sealing to resist mechanical stress and harsh environmental conditions in heavy-use or safety-critical applications.
TOP QUESTIONS TO ASK WHEN SELECTING CABLE FOR HARSH ENVIRONMENT APPLICATIONS KEVIN DEPRATTER, DIRECTOR OF R&D, NORTHWIRE
Failure-proof cable selection starts with an evaluation of how the cable will be used and the environmental conditions that surround the application. This is especially important in dangerous or harsh environments where water, sunlight, temperature extremes, chemicals, dust, or other hazards are present. Constant motion or twisting can cause internal conductor bundles to corkscrew, which can result in conductors breaking. Constant motion or flexing can create internal heat and abrasion, which may cause inner conductor insulation to fail and then short circuit. Other environmental factors, such as the presence of oil or chemicals, combined with constant motion, can accelerate the failure of the cable’s outer jacket. Jacket failure in harsh environments that produce high heat or abrasion exposes the inner conductors to the elements. TO PREVENT FAILURE, ASK (AND ANSWER) THE RIGHT QUESTIONS Gather the necessary information about how and where the cables will be used. Start with the basics. • What are the specifications? • What is the environment of the application? What temperatures will the system operate in? If motion and flex are likely, will they be constant? Will the cable be exposed to oil, chemicals, UV
rays, or welding slag, and if so, for how long? • How will the cable be installed, connectorized, and terminated? • What agency standards, government regulations, and other approvals are needed? • Are there aesthetic requirements for the finished cable assembly’s look and feel? • What are the scheduling and budget parameters?
RUGGEDIZED CABLE COMPONENTS
STRENGTH MEMBER PERFORMANCE Strengthening materials are added to improve pull strength, push strength, mechanical strength, or rigidity. Common strength members are fiberglass rods, steel, and aramid fibers. What to ask when choosing strength members: • What types of strength are required? • Does this cable need to be rigid or flexible? • What is the plan for connectorization and termination? MULTI-FUNCTIONAL TUBING Breather tubes are necessary for maintaining functionality in certain extreme environments, offering enhanced protection against heat, abrasion, pressure, water, oil, chemicals, and flame. Breather tubes can be used to bundle inner components in wiring harness applications for protection and abrasion resistance, gas and fluid transfer, and for dissipating heat, pressure, or steam. What to ask when selecting tubing: • What is the primary purpose of the tube? • What secondary functions for the tube are desired? • Will the cable be in high heat or wet environments? • What material will best meet the needs of the application (polyethylene, nylon, polyvinyl chloride, polyurethane, or fluoropolymers)? WATER-BLOCKING MATERIALS Water-blocking agents react quickly to seal off any leaks and prevent liquid from migrating. Newer solutions allow for ease of installation and termination. They include dry yarns and tapes impregnated with water-blocking chemicals that activate when they come in contact with moisture
to produce water-blocking gels and successfully trap and seal the leak.
What to ask when selecting water-blocking materials: • Will the cable be partially or fully submerged? • Are there moving parts or high flex requirements for the cable system? • What types of liquid will the cable encounter? FILLERS FOR FORM AND FUNCTION The primary function of filler material is to fill the space between components to create the desired form, but they can also be used to enhance functionality or add strength and protection against harsh environment conditions. Fillers are typically made of polypropylene, polyester, nylon, cotton, and paper that can be bundled, twisted, or layered. Each material offers specific benefits. For example, polypropylene rods add push and pull strength, polyester provides insulation, nylon resists heat, cotton will not melt in high temperatures, and paper has options for flame and moisture resistance. What to ask when selecting filler materials: • What is the desired form? • How can filler enhance the cable’s function? • What gaps could various filler materials address for this application? BARRIERS: TAPES, WRAPS, AND SEPARATORS Barriers are mainly used to prevent the cable’s core components and the outer jacket material from bonding together. Configurations to isolate and separate internal components are highly customizable. Additionally, coverage can range from full to minimal depending on needs.
Some tapes, wraps, and separators can also perform additional functions. • Aluminized backing can be used for shielding and insulation. • Binder wraps hold components together to make sure tensions stay the same. • Some tapes can increase flex life or rigidity. Others are specifically designed for high or low temperatures, or for use in any temperature. • Wraps and tapes can be designed to protect cable or components from moisture and chemicals. What to ask when selecting tapes, wraps, and separators: • What internal components must be accommodated? • What other functions would be helpful for this application? • How will the cable be connectorized? • Will the choice of material affect the connector housing? SHIELDING FOR STRUCTURAL AND SIGNAL INTEGRITY Shielding protects the cable by increasing structural integrity and signals integrity. With the right materials and configurations, shielding can also add strength, flexibility, and noise suppression. Shielding is accomplished with aluminum foil tape; aluminized polyester tape; foil tape, braiding with tinned copper, stainless steel, bronze, and other materials; or drain wire. A combination of braid shields, which guard against low frequency noise, and foil shields, which guard against high frequency noise, is most effective against interference for maintaining signal integrity. Braiding styles are either
box weave or spiral.
What to ask when choosing shielding: • What type of noise interference will the cable encounter? • What are the flex life demands for the cable system? • What is the plan for connectorizing multiple shields? JACKETING PROVIDES DEFENSE AGAINST HARSH ENVIRONMENTS The outer jacket is a cable’s main protection against environmental stresses and application demands. For medical and food grade applications, polyurethane, thermoplastic rubber, and polyvinyl chloride are used. Options for other applications include fluoropolymers, polyester elastomer, thermoplastic elastomer, and thermoplastic urethane. In some cases, a specialty blend is appropriate to meet specific, unique needs. What to ask when choosing jacket materials: • Will the cable be subjected to extreme temperatures? • Is cut, crush, or abrasion resistance required? • Are there low smoke, zero halogen (LSZH) requirements? • Are there medical or food grade considerations? CONSIDER THE CONNECTOR The connection is often the part of the assembly that is most vulnerable to the elements, so attention to terminating and connectorizing the cable is critical. The connector must have its own protection against the elements and operating conditions that exist in harsh environments: extreme temperatures or temperature fluctuations, chemicals, water, dust, sunlight, radiation, and more.
work as promised, so great care must be taken in the design, selection, installation, and operation of all the connectivity components.
Harsh environments often have limited access and the connector and cable assemblies used in them may be expected to perform critical operations for decades. Whether in space, in a nuclear power facility, in medical equipment, or in a military application, someone is relying on that equipment to Waterproof IP68 LEMO T Series push-pull connector assembled with Northwire cable provides a rugged connectivity solution for many harsh environment applications. Push-pull self-latching provides quick operation and maintains a secure connection if cable is tugged.
Waterproof IP68 LEMO M Series ratchet-coupling connector assembled with Northwire cable provides a rugged connectivity solution for many harsh environment applications. Ratchet coupling provides quick 3/4 turn to mate and de-mate and maintains a secure connection if cable is tugged.
Visit Northwire to learn more.
UNINTERRUPTED CONNECTIVITY SOLUTIONS FOR HARSH ENVIRONMENTS LUC KAN, GENERAL MANAGER, AMPHENOL LTW TECHNOLOGY CO. LTD.
give designers solid options: check and match, customize a standard offering, and full customization. CHECK AND MATCH In this approach, the customer’s specifications, such as electrical, mechanical, environmental, and chemical, are matched against existing
Harsh environments include any situation that puts a strain on equipment. Extreme cold and heat (or wide temperature fluctuations), deep water immersion, direct UV exposure, water or dirt ingress, corrosion, high vibration and shock, and difficult access all require connectivity solutions that are rigorously designed to withstand extreme operating environments. Off-the-shelf products specifically engineered for the
offerings. Search results may include specific products that exactly or closely match the requirements. The customer can review comparison charts for each potentially compatible product. Slight modifications such as cable lengths, material colors, and labeling are part of this option.
market segment can be an effective option. However, customization offers the flexibility of a total solution that fully matches the technical specifications of the area of deployment and the underlying peripherals involved.
FULL CUSTOMIZATION IS GENERALLY A LAST RESORT FOR WHEN THE FIRST AND SECOND APPROACHES
DO NOT PROVIDE AN ACCEPTABLE SOLUTION.
To secure the best solution for a particular application, designers and engineers should work with a supplier that has a system to carefully assess the needs and constraints of the project. Three approaches
CUSTOMIZATION OF A STANDARD OFFERING This approach creates a custom solution based
on a standard tool of existing products. Several factors may lead to customization. The most common is the need for a higher electrical rating with a specific number of electrical contacts. To meet these requirements, the pin housing is modified to accommodate the larger size contacts with an ample amount of spacing between polarities to meet the electrical safety and mechanical strength. FULL CUSTOMIZATION Full customization is generally a last resort for when the first and second approaches do not provide an acceptable solution. There is an upfront investment, but in most cases, full customization will resolve all technical issues and provide the best solution for unique customer needs. In some cases, customers have already designed the products, for example, in the case of OEM items. In this situation, the supplier will only tool up the molds and manufacture the products without major changes. Recommendations and slight modifications may be implemented but will not greatly deviate from the original design. SELECTING THE RIGHT SOLUTION Several parameters need to be considered in selecting connectors and cables. These will mainly depend on where the product will be deployed, which is typically a function of market segment or the industry in which the connector and cabling system will be used. Each of these industries and markets has its own extremes and variations of harsh conditions. For instance, in the marine market, the connectors need to have an extreme corrosion-resistant component, as this equipment will be exposed to salt. The cables should have a rating for marine application or comply with standards defined by regulating bodies such as ABYC
and NMEA. Exterior components should utilize non- metallic materials or a metal alloy that can withstand long salt mist exposure, and a cable insulation and jacket that will not react to chemicals present in the operating environment. In automotive applications. connectors need to withstand high vibration and mechanical impact as defined by USCAR. These connectors need to be constructed with ruggedized components that have high mechanical strength, and the cable and wire harnesses must be made with automotive-grade materials. The coupling mechanism should also be selected based on assembly method, accessibility, exposure to shock and vibration, and other relevant factors.
FOUR MAIN PARAMETERS OF INDUSTRIAL SETTINGS: ELECTRICAL, MECHANICAL, ENVIRONMENTAL, AND CHEMICAL The electrical capacity or load is based on UL and EN standards. The connector is tested to show that it can withstand any intermittent influx of current or Amphenol LTW Technology Co.’s quick-connect system is available in a variety of options to serve most applications. However, in the automotive industry, ALTW recommends a screw coupling between a connector pair to withstand extreme vibrations and frequent movement.
voltage transient during its normal operation. The electrical parameter’s attributes – how the contacts will be insulated and how the contact’s sizes should be made in reference to its electrical conductivity and to the current it is conveying — have similar requirements in most applications. However, some market segments require additional safety features. For instance, if the end product will be directly accessed by the user, an additional safety feature could add more depth to the female contact’s touch point relative to its housing surface. Doing so will ensure that the end user will not accidentally touch the live contacts with fingers or tools. The materials used in the contact housing and its backshell should be able to withstand the electricity and heat generated during the equipment’s operation. The electrical contact material will be based on the kind of electrical signal it will transmit, power or data.
not be disrupted or the contacts dislodged when subjected to impact. The geometric layout must be carefully calculated and the positioning of its features will adhere to UL and EN standards. The selection of materials will then rely on the pre- defined specification. These include how frequently it will be mated, interface keying to prevent wrong polarity linkage, and what kind of pulling and lateral force it will bear upon deployment. Though a singular material can be selected to cater to a wide range of applications, it will not be cost-effective if some of its mechanical properties will not be utilized during a particular operation or in the intended market segment. Thus, use of a material that will serve the purpose with fewer features makes more economic sense. The environmental parameters also vary depending on the product’s application. For applications in subzero or extremely high temperatures, the materials used, particularly the plastics on housing and cables, should not fail or break when subjected to dynamic operation and impact. The materials used throughout the component should preferably have similar coefficient of thermal expansion (CTE) so all parts expand or shrink at the same rate. The degree of protection is therefore uncompromised, particularly regarding the connector’s ingress protection. Materials used in applications that require direct exposure to sunlight or UV must be resistant to it and be rated for outdoor use. Lastly, the chemical parameters will define the product’s material resistance to certain chemicals. The selection process of material to be used on the products’ components will rely on the chemical hazards that the product will encounter in the
In the mechanical parameters , the connector components’ construction derives from the product’s application and what kind of physical abuse it will undergo during operation. The primary consideration of the connector’s mechanical design is the integrity of the transmission of electrical signals. They should ALTW’s contacts typically utilize copper alloy with high electrical conductivity (current capacity per unit area) to optimize space, making the connector more space- diversified and occupying more electrical contacts. Due to this, heat generation during conduction is also of utmost importance in ALTW’s contact design; the current rating was derated to prevent unwanted burnouts and joule heating. For an application that required hot-plugging, a special contact design was implemented to prevent arcing during operation.
ALTW’s outdoor products can always be used for indoor applications but not the other way around. Meanwhile, some indoor applications require special plastic types that emit less smoke and zero toxic fumes when combusted. This requirement is quite common in the LED lighting market and its horticulture sub-segment.
operating environment. In the automotive industry, most of these are from fuels and oils. Thus, the materials should have at least a good rating; lower ratings mean the product may deteriorate quickly. The four main parameters are interdependent in the sense that the final selection of materials to be used in the product’s design depends on the data for these parameters – the material should satisfy the specifications for electrical, mechanical,
environmental, and chemical. These comprise the underlying foundation for producing products that meet the specialized requirements of a particular market. Without this, the ruggedized connector will not be a success.
Visit Amphenol LTW to learn more.
UNRIVALLED PERFORMANCE IN CRITICAL ENVIRONMENTS SOLVES INTERCONNECT CHALLENGES CHIARA PIERI MARCOM MANAGER SMITHS INTERCONNECT
2. Proven technical characteristics of the product technology 3. Product compliance with the main international standards for the relevant market Choosing the right product materials is an important step toward ensuring that the connector will provide a stable connection despite being subjected to a variety of harsh conditions. Connectors that are lightweight and compact have the added benefits of cost- and space-savings. A connector with very low contact resistance ensures the minimum temperature rise at high currents. The peak temperature of the insulator material is
From satellites and next generation aircrafts to life- saving defibrillators and railway systems, connectivity requires superior quality products that offer great performance and optimal reliability under extreme temperature, mechanical shock and vibration, difficult access, water or dirt ingress, and fretting corrosion. To ensure reliable signal integrity by keeping the product undamaged through a long-life cycle, the manufacturer itself needs to guarantee three key aspects:
1. Selection of rugged and appropriate product materials
normally the primary limiting factor in demanding conditions. Materials must be chosen to support the widest ambient temperature range (from –55°C to 125°C) and withstand temperature peaks during assembly, even those generated during vapor phase soldering, while complying with the rail market requirements for fire and smoke.
To gain assurance that the connector’s quality is suitable for current rail and industrial standards and that it can maintain exceptional connectivity for devices in high-speed trains or other harsh environment markets, it must hold up through tests of reasonable duration that simulate the service conditions seen throughout its expected life. These tests include endurance, contact retention and resistance, insertion loss, salt spray, dry heat bake, and fire resistance.
CONNECTORS FOR SPACE Space applications are a perfect example of the importance of unrivalled performance in critical environments. Interconnect solutions for space must meet the reliability and efficient design needs of today’s satellite and spacecraft challenges. Space satellites are moving away from RF analog-based Smith’s Interconnect’s new Intercompact series is a lightweight, compact signal and Ethernet PCB connector specifically designed to provide a stable connection in demanding rail and industrial applications. The Intercompact series has been qualified in compliance with the main European railway standards.
CONNECTORS FOR RAIL AND INDUSTRY Connectors must meet the main European railway standards (EN45545-2, NF F61030, EN50155:2017, STM-S-001ind.D, and more) and comply with MIL-C-28748 and MIL-STD-202-301 standards and EIA and IEC standards for contact resistance and environmental testing. The shape of the contact sleeve in Smiths Interconnect’s Hypertac socket is formed by hyperbolically arranged contact wires, which align themselves elastically as contact lines around the pin to provide multiple linear contact paths, giving the product immunity to shock and vibration.
Smiths Interconnect’s SpaceNXT initiative is a full range of higher reliability products for next-generation space applications with a lower cost of ownership.
payloads that provide low-speed telecommunication signaling to a new Digital Transparent Processor (DTP) architecture for high throughput satellites. DTP architectures increase the demand for rugged and higher speed connectivity. Satellite manufacturers often use large singular printed circuit boards featuring very high value components. The solderless PCB mount design that the NXS Series provides, for example, can be placed and replaced with very low risk to the customer’s board, reducing the cost of ownership. The connector is mounted after reflow and has no impact on nearby components. Each product is engineered using 3D electromagnetic simulation (EM) software to provide excellent performance in a total thin film process. Smiths Interconnect’s NXS Series is an advanced high- speed, high-density interconnect equipped with the proven Hypertac hyperboloid contact technology to withstand data rate application requirements up to 10 Gb/s (per channel), including extreme levels of vibration, shock, and climatic testing above 2100 G. The NXS Series is designed in a robust construction with 4 or 12 high speed quadrax modules containing 2 dual twinax at 100 Ω each pair. This ultra-high contact density and compact form factor allow the customer to make a 90˚ transition within a very small footprint. It is blind mateable, hot pluggable, with ultra-low mating forces, and low outgassing materials.
Meeting those industry needs requires high-speed, high-density interconnects that can provide next- generation data on demand and can withstand high data rate application requirements, including extreme levels of vibration, shock, and climatic testing above 2100 G. To be qualified, they must meet rigorous testing and performance criteria ESCC 3401, ESCC 3402, ECSS-Q-ST-70C, ECSS-Q- ST-70-02, ECSS-Q-ST-70-08C, ECSS-Q-ST-70-38C, and ECSS-Q-70-71. The selection of rugged, qualified, and dependable materials combined with proven, reliable, and flexible contact technology and full compliance to industry standards is critical to creating successful connectivity solutions for the challenges presented by space.
Visit Smiths Interconnect - High Reliability Connectors Solutions to learn more.
ADAPTING CONNECTORS FOR HARSH ENVIRONMENTS
HARSH ENVIRONMENTS REQUIRE MODIFICATIONS TO COMMON CONNECTORS PETER SWIFT PRODUCT MARKETING DIRECTOR AMPHENOL COMMERCIAL INDUSTRIAL PRODUCTS
The surge of Industry 4.0 and the Industrial Internet of Things has led to an explosion of interconnected devices and equipment for use in challenging environments that still use common standardized electrical interfaces. This has driven the need to eliminate some of the design limitations of commodity interfaces such as RJ, D-Sub, and USB connectors by creating ruggedized versions for use in harsh environments.
to describe naturally occurring environments such as extreme cold climates or the hot arid conditions of deserts. Factors such as moisture and pressure can combine with extreme temperatures in natural environments like tropical rainforests, high altitudes, and deep underwater. These conditions also occur in manmade environments such as manufacturing or processing plants and all types of vehicles. Equipment in these conditions may face exposure to caustic chemicals, airborne particulates, or vibration, shock, and impact.
The term “harsh environment” can refer to a variety of challenging operating conditions. It can be used
Interconnect products and systems must be designed to ensure that such equipment will function reliably. Many interconnects have very specific requirements and features depending on their primary function, making them ideal for some applications but completely unsuitable for others. A connector intended for use on an oil rig to power equipment on the exposed outside platform must be mechanically strong, designed for rough handling, and impervious to oil, saltwater, and extreme temperatures, but wouldn’t be expected to be used in a motor vehicle or on a commercial jet. These applications have their
own specific sets of conditions that require other features and design criteria.
Many connectors are anything but specific in their use. The modular jack, the D-sub, and the USB may have been created for a specific use; the modular jack, or RJ (“registered jack”) connector was initially designed as an inexpensive interface for telephones, for example. But RJs have been adapted for use in thousands of different applications in multiple markets. The RJ connector can now be found in virtually every type of equipment imaginable,
including a wide variety of industrial and consumer products. The D-Sub connector has been around since the 1950s, and one of its initial applications was as the standard for RS-232 and RS-485 communication, connecting peripheral devices such as keyboards and printers. It was also one of the primary interfaces used for creation of extensive networks between electrical devices in industrial settings. But D-Subs are now used in almost as many different applications as RJs, given its versatile and robust design. The USB connector was later developed to replace D-Subs for connecting computer peripherals, but once again this interface has found uses far beyond its original applications. These interfaces are widely used for so many applications because they have proven to be highly adaptable, and as such have become standards, making them inexpensive, highly available, and reliable. As a result, many types of equipment have been developed using these interfaces for their I/O connections, providing the signal, data, and power ports, and using widely available standard cables and plugs. These connectors have benefitted from multiple adaptations in mounting and termination styles, as well as electrical performance enhancements. For example, the RJ has been improved with clever contact designs and embedded signal conditioning features and, when combined with data protocol evolution, allow it to operate at higher data rates suitable for Ethernet and other networking applications. While such interfaces have typically been designed as touch-proof, IP20-rated connectors, they typically feature stamped metal shells, plastic insulators, and stamped metal contacts, none of which are suitable for use outside of a relatively dry, temperature- controlled environment.
Ruggedized RJ45 connectors (top) and standard versions (bottom). The die-cast housings of the ruggedized connectors and the external panel sealing gaskets ensure much greater durability and sealing protection than the standard connectors.
Figure 2. D-subs are highly adaptable with many mounting and termination options in both Ruggedized (top) and standard (bottom) variants.
They won’t stand up to anything more than a very slight physical impact without suffering from a bent shell, broken plastic insulator, or damaged electrical termination to the equipment they are part of, damage that would render them inoperative. They certainly are not designed to prevent liquids or dust from getting into the equipment they are mounted to, which could lead to permanent damage.
Ruggedized versions of commodity interfaces give manufacturers the benefit of using connectors that are designed, tested, and qualified for a given environmental application, and the confidence that their finished product will be reliable. High- performance, ruggedized variants of standards- based connector interface solutions provide tangible value. Ruggedized USB connectors are available in single and multiport versions with single-piece die-cast housings allowing easily customized mounting configurations to be created. Standard varieties cannot be easily sealed, and the stamped metal housings are easily damaged.
For success, ruggedized versions must address these design criteria:
1. Maintain the standard mating interface so that they can be used with any standard cables, just like the non-ruggedized versions. 2. Maintain the original form factor as much as
A piece of mobile equipment incorporating ruggedized, sealed standard interface connectors. These connectors allow standard IP20 cables to be connected, while still protecting the equipment from dust and moisture, and shock and vibration.
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