TECHNOLOGY IN CONTEXT
Small Modules in Rugged Environments
Rugged Electronics Rapidly Adapt to New Applications
VITA 59: RCE, the result of cooperative efforts between VITA and PICMG, is bringing the modular, small form factor advantages of COM Express to the world of systems that require ruggedization, opening a wide range of new and exciting applications for small embedded systems.
BY MICHAEL PLANNERER, MEN MIKRO ELEKTRONIK
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The broadened availability of rugged electronics has led to the use of embedded systems in applications previously not able to take advantage of the latest developments in embedded computing. Not only are existing markets benefitting, but completely new markets are opening up, since electronics can now reliably be used in places where previously they just wouldn’t survive.
Specifically, embedded technology has found its way into a wider variety of mobile and small form factor applications enabling a new set of technological innovations in fields as diverse as mobile medical equipment, industrial agricultural machinery and mass transit vehicles. Ruggedization of the systems and components has laid much of the groundwork for this growth.
Today’s embedded systems are found in portable applications as varied as rolling X-ray and MRI machines to buses, railcars and even airplanes. This seemingly diverse set of equipment has a few key points in common. Namely, each is based on being mobile, which brings shock and vibration into play, as well as being subjected to rigorous environmental effects such as dust, humidity and heat or even cosmic radiation in airborne applications.
Available space is also a concern in each piece of equipment, regardless of the specific industry. Real estate in electronics systems is shrinking in two significant ways. On the outside, in terms of physical space, there is less room for the actual system or board to fit into, especially in the case of space-constrained applications. On the inside, more components are fighting for this reduced system space, and yet the systems are expected to incorporate more functionality, which often translates into more components, or integrated components, which brings the concern of heat dissipation into play. So, how does a designer overcome this battle of developing a rugged, reliable system within very tight quarters, and do it cost-effectively?
The degree and intensity that each element in an embedded system endures varies depending on the intended application, which drives component choice in overall system design. Ongoing developments in components, technologies and the standards that govern embedded systems have led to a growth in the choices designers have to match a system to their application requirements.
Ruggedization needs to be an inherent concept in the initial development of the component design, not just added as a consideration after product development or after certain parameters are already defined that will influence how the product operates. True ruggedization is best achieved at the first steps of a component’s design. (Figure 1).
Taking it to extremes, compact, rugged electronics handle today’s most severe application environments.
The embedded industry has seen its share of ideas that work and those that maybe could have been done a bit differently. But one thing is clear: a healthy ecosystem that involves several industry manufacturers and that offers customers flexibility, options and enhancements gives a technology platform a much better chance of not only surviving, but of thriving.
Standardization promotes growth in an ecosystem in several critical ways. The availability of a universal platform enables users to develop systems that talk effectively with one another. It also ensures that components work side by side in a system, not against one another; and it fosters a community of developers and manufacturers that work together for the growth of the industry as a whole.
In addition to providing a network of manufacturers that gives the end user supplier choices and various development options, a standardized platform facilitates rapid system design time and greater flexibility. Currently in preparation, VITA 59: RCE (Rugged COM Express) provides embedded designers with a compact format, an industry standard platform and rugged performance. (Figure 2).
A standardized platform ensures a healthy, growing ecosystem.
Based upon the PICMG COM.0 (COM Express) standard, VITA 59 not only capitalizes on the small form factor and interchangeable concepts behind this original standard, but also adds ruggedization and modern serial interfaces while defining pin-out for compatibility among different modules, regardless of manufacturer (see sidebar “A Chapter on COMs,” p. 15). It is also the first collaboration between PICMG and VITA to set forth an industry standard that will facilitate the embedded computing community as a whole.
The VITA 59 RCE standard uses three of the four widely accepted form factors of PICMG’s COM Express, along with all the associated mechanics and pin-out requirements. Within those form factors, a VITA 59 module has provisions for a 5 mm wing extension for cooling and mounting (Table 1).
Standardization Aids Optimization
A number of factors working within the standard can aid in optimizing designs. The inherent modularity enables a building block approach to system design for rapid development of customized systems components. Since key technology parts are standardized, and therefore require minimal or even no development time, resources can be focused on the application specifics. Standardized modules can easily be replaced or upgraded, extending overall system longevity. Because the components are based on the same standardized platform, integration is simplified, reducing costs as well as time-to-market. Ruggedized COMs modules can be tailored for a range of platforms from low power up to high performance environments, and the established pin-out and PCB size guarantee intercompatibility.
The use of flexible I/O configurations gives designers a wide range of choices in system design and functionality. A module can be cost-effectively and easily adapted to its application in terms of functionality and environmental concerns, including shock, temperature, vibration, dust and humidity.
VITA 59 provides enhanced EMC protection to reduce risk and qualification costs as well as additional mechanical protection against shock and vibration, enabling the modules to be used in harsh applications, such as railway and military systems. The sealed design keeps the electronics free of humidity and dust, which could compromise the electronics.
Thermal Management is also a vital aspect of ruggedization. By their nature, smaller systems are frequently more affected by heat build-up and the need to protect electronics from associated damage. The VITA 59 design accommodates functional operating temperatures ranging from -55° to +125°C through heat transfer properties built into the CPU as well as the choice of connector and the solid connections between the chip, the module frame and cover, and the carrier board. Heat from the CPU is transferred to the metallic top cover and then to six cooling tabs that mate with the module frame for conductive cooling. Supplemental cooling is also possible by applying a heat sink to the top of the module cover.
New Vistas of Applications
Medical: Ten years ago, moving a patient on a ventilator in intensive care involved some critical risk factors, since the unit would need to withstand the wobbles in an elevator, numerous bumps over door jams and jostling around corners, through hallways and positioning within the room. However, now through the use of ruggedized, compact electronics, developments are being made that are facilitating patient care and increasing quality of life.
Rugged electronics are being used to control ventilation in mobile medical equipment, while monitoring patient vitals. In one example, a carrier board was developed by the equipment manufacturer that included system functionality with application-specific I/O that met the patient monitoring and ventilation control requirements (Figure 3).
Life-critical medical systems are relying on rugged electronics for reliable operations and advanced patient monitoring.
These devices need to work in close proximity to several other pieces of medical equipment, all of which are crucial to patient safety. EMC, in terms of how the ventilator was affected as well as how it would affect other devices, was therefore of the utmost concern. Extremely low EMC values and high ESD requirements were met through the VITA 59 specification, since the rugged module is sealed in a 100% EC-protected housing.
Since it is regulating a patient’s breathing, interruptions in performance, even for a split second, would be detrimental. The system is designed to withstand severe shock of up to 25G in addition to vibration up to 2.5G, ensuring that no matter where the patient needs to be transported, the system electronics will continue to function, ensuring patient safety.
Transportation: Ruggedized electronics are not only helping to transport individual patients safely, but are also being used in mass transportation applications to move much larger numbers of people on a daily basis. Today’s modern rail system is finding many benefits in small form factor ruggedized electronics.
From the rail system itself down to the specific train cars, electronics are being used to automate, facilitate and accommodate the vast amount of data that keeps the trains running on time, passengers informed, and the system operating efficiently and safely.
Starting with the engineer of a train, Rugged COM Express is being used to update the display within the train cab to allow the engineer access to the growing amount of data available on a railway network. The added computing power of the system’s AMD processor, combined with the ruggedized electronics, brings more data to the engineer quicker without the threat of the system going offline.
For example, an IP65 front plate on a display, complete with touch keys, gives the engineer easy access to system information while ensuring the display will be unharmed by environmental elements including dust and humidity. Conformal coating on the electronics will protect the internal workings of the system to ensure reliable operation over an extended period of time.
On the rail network itself, system designers are implementing more advanced and rugged electronics for the central control as well as remote control and diagnosis. One freight train manufacturer is using a completely customized system that is still fully compliant with the European railway standard EN 50155.
The use of VITA 59 components allows the cars to be equipped with highly advanced electronics that fit in very small spaces, yet ensures that the system meets the standards set forth by the governing industry-required specifications. Shock, vibration and protection from the elements are also considerations of this rugged operating system, along with passive cooling from -40°C up to +125°C.
Construction: One of the newer application areas using small form factor, rugged electronics is the construction industry. Previously, the extremely high shock and vibration found in this industry had precluded most embedded electronics from truly being utilized in construction equipment (Figure 5).
However, because it caters to both the rugged and compact requirements of construction equipment, VITA 59 is forging new ground in terms of where embedded computing systems can be used. This trend is set to continue as electronics are expected to perform reliably in a growing number of compact and mobile environments.
Not only does VITA 59 provide a standardized method for implementing rugged electronics in compact environments, it also aligns the principles of two important industry organizations. In essence, it highlights the advantages of both PICMG and VITA to establish tomorrow’s platform for reliable and rugged embedded computing.
An ecosystem can only survive if there is growth and support from within. As evidenced by the use of rugged electronics to modernize older systems as well as to provide inroads into new applications, small form factor electronics will continue to proliferate into different embedded environments, providing long-term reliability, advancing electronics and solid performance well into the future.
MEN Mikro Elektronik
Blue Bell, PA