Industrial
Advancements in harsh environment circular connectors fuel modernisation
By Geraint Davies, business development manager at TT Electronics R
olling stock vehicles are facing a spectrum of modernisation challenges – from hybridisation that reduces carbon output to sophisticated onboard applications that keep passengers safe and happy. Designers have to think ahead, keeping modernisation in mind and bracing for increasingly data-rich and high power applications that must be designed for the rigors of train-borne computing. Harsh environment circular connectors are a key part of this puzzle, playing a vital role in reducing vehicle weight, minimising system footprint, and increasing design flexibility with modular options. While rectangular connectors have long been known for their modularity, these options only allow manufacturers to choose various inserts as a means to customise performance to a necessary configuration. In contrast, circular connectors are manufactured to exact customer needs, purpose-built to offer the specific contact arrangements for the application at hand. While the design approach is somewhat different, the result is a similar level of customisation but usually in a lighter, smaller footprint. These values closely align with the need for manufacturers of railway systems to remain competitively poised for modernisation and the continued addition of unique and complex onboard systems.
Choosing harsh environment circular connectors
Connector choice is an important consideration early in the design phase, as committing to one connector platform or another typically lasts for the duration of the rolling stock vehicle. Standards compliance is required on any harsh environment connector, which must meet stringent levels of IP protection, shock and vibration, temperature cycling, and protections
against fire and toxicity outlined in standards such as EN45545, NFPA130, and others. Albeit a connector can be perceived a minor part of the system, it is vital this connector interface selection is correct first time. A failure of a connector in service, would be considered to be a failure of the system and potentially having detrimental effects to the image of the system manufacturer.
Screening advancements in circular fittings
Connector EMC performance plays an important part of rail system demands. To maximise this performance, cables’ screen termination should be made inside the connector itself, a unique value demonstrated by TT Electronics’ SteadiShield connector series. This performs in contrast to a traditional connector assembly, where screening generally adds length and complexity when building the electrical harness assembly.
A major railway manufacturer provides a real-world example of screening improvements in action. The firm manufactures braking systems for rolling stock vehicles; it had run out of room on its new braking system. Instead of a single connector for controls, signals and more, the firm needed to blend all these capabilities with high performance data transmission. The rail manufacturer also typically required the use of a specific accessory on the back of the cable as part of the screening process, as well as the use of a defined braid of cable. In collaboration and in a design-to- production process of less than six weeks, the firm’s connector partner developed a circular connector solution that combined an Ethernet data contact and multiple signal contacts in the same connector interface. At the same time, the termination of the Ethernet cable
screen was simplified – screening was instead conducted as a part of the connector design, eliminating cumbersome back-end fittings even as screening remained constant from outer contact to the shell of the connector and still managing to isolate the signal contacts. This same connector has the ability to accommodate a variety of contacts including coaxial through to 10Gb Ethernet cable for CAT 7 cable. The overall length of the connector was reduced, weight was reduced, assembly time became shorter, and EMC performance of the connector was improved. These advances are also applicable to operations such as advanced railway signaling, comprehensive surveillance, high speed connectivity for passengers, and passenger count systems that streamline ingress and egress. This growing slate of real-time applications continues to increase the load on connectors and demand smart, high performance design strategies from connector designers.
Circular connector values are optimised for modernisation This industry need is also demonstrated in global initiatives such as the European Rail Traffic Management System (ERTMS) as well as its North American counterpart, Positive Train Control (PTC). These programs will add new control systems intended to increase passenger safety, for example managing train acceleration relative to the bend angle of track. The circular 10Gb Ethernet option adds tangible value in this setting, offering speed of data with flexible configuration that minimises footprint and weight. Validated to rugged standards for mission critical performance, these connectors can run throughout and between carriages. In the process of retrofitting older vehicles with new equipment, harsh environment circular connectors are proving to be important
26 September 2020 Components in Electronics
building blocks that address performance as well as space limitations.
Other high performance applications face similar challenges: the Ethernet backbone onboard most railway vehicles, Wi-Fi systems, CCTV surveillance, passenger count and information systems, and much more. As these applications need to share and access data faster, connectors and cables will have to deliver real-time feeds for numerous applications simultaneously. Connector strategies are crucial, anticipating configurations with large multiples of contacts generated by twinax, triax, and quadrax designs.
Validated to harsh environment performance, circular connectors can deliver the speed of data required in a small footprint with less mass. Internal screening inside the connector itself furthers this value, reducing overall connector length and increasing EMC performance. Flexibility rounds out the path to modernisation, with connector designs tailored to meet exact applications requirements for optimised performance today and in the future.
ttelectronics.com
About the Author
Geraint Davies, business development manager at TT Electronics
Geraint has an extensive and broad background in the Connector industry previously holding roles in Engineering and Project Management before specialising in Business Development. He is also extremely passionate and experienced in supplying and developing solutions specifically for the rail sector. Connect with Geraint at geraint.davies@
ttelectronics.com or via LinkedIn.
www.cieonline.co.uk
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