While industrial applications typically require high levels of reliability, availability, ruggedness, and longevity, there often is a set of unique system requirements dependent upon the specific goals of the system. For instance, an industrial automation application may call for a particular I/O interface or the ability to support custom control software.
Unfortunately, no universal computing solution exists that can satisfy all of the varying needs for the growing range of industrial applications. The good news is that recent advances in technology have opened up a variety of new standardized options. The amount of performance that can be squeezed into a small form factor has improved dramatically in part due to advancements in processing technology. For instance, the new Intel® Atom™ processor Z5xx series was developed specifically to address very compact, performancehungry, and thermally constrained embedded applications.
Many popular embedded computing platforms are taking advantage of these innovations to provide the critical building blocks for embedded industrial and rugged systems. The following provides an overview of some of the latest off-theshelf embedded solutions now available in industry-standard form factors (see Table 1).
The Computer-on-Module (COM) approach offers the advantages of high levels of processing performance and I/O bandwidth in a compact form factor. It also allows flexibility in standard form factor boards that require upgradeable host functionality.
Embedded Technology eXtended (ETX) has established itself as a popular non-backplane form factor. Targeting customizable embedded requirements, ETX offers reliable operation and a long life in harsh environments. Since ETX modules employ heat-spreader plates to assist with conduction cooling, they are an option for use in extended temperature ranges as long as the components in the design can tolerate the harsh environment.
The newer ETX 3.0 specification offers all of the benefits of the original ETX standard while adding in 2x Serial ATA without changing any of the ETX pin definitions, making new modules 100 percent pin-to-pin compatible with previous versions to ensure long-term support for the vast number of embedded application solutions based on these already highly integrated COMs.
COM Express includes specifications for small-form-factor modules to satisfy the high-performance segments of the embedded industry. The COM Express standard currently includes “basic” and “extended” form factors following one of the five PICMG-defined pin-outs. In addition to offering “basic” modules with the ETXexpress product family, two compatible smaller form factor modules — microETXexpress and most recently nanoETXexpress (as illustrated in Table 2) — have been developed. The nanoETXexpress modules have a footprint just 39 percent of the original COM Express standard “Basic” form factor module.
Perhaps the biggest concern for MicroTCA is ruggedization. The PICMG standards body has a subcommittee investigating standardizing rugged implementations of MicroTCA, and ruggedized MicroTCA options are already available. Concerns about the MicroTCA edge connector become less of an issue in conduction-cooled deployment, because each card is physically bound to the chassis. For this reason, it is possible that conduction-cooled MicroTCA will become common before “soft rugged” implementations that do not require conduction cooling.
CompactPCI’s high bandwidth, ruggedness, and familiar computing paradigm have made it a preferred form factor for many types of applications. CompactPCI is available in both 3U and 6U form factors to meet connectivity and rear I/O requirements, providing a versatility attractive to system designers. CPU blades allow a CompactPCI solution with the same processor and chipset to be deployed in rugged air-cooled or conduction- cooled systems, via either a 3U or 6U processor blade. Both boards provide similar capabilities and connectivity, which gives the system engineer the building blocks needed for maximum flexibility when selecting architecture. As the pressure to reduce size and weight intensifies, the smaller 3U CompactPCI is gaining popularity. The 3U form factor also offers ruggedization benefits due to its significantly greater stiffness, making it less susceptible to shock and vibration.
VME boards and platforms continue to have a secure foothold throughout applications that demand ruggedness and reliability. Similar to CompactPCI, VME is available in the 3U or 6U form factor, offering designers several options when it comes to design choices. While its traditional stronghold has been in military and aerospace applications, VME is rugged enough for most industrial applications.
With a rich set of I/Os including serial interfaces and fieldbuses, VME has a great deal of communication power ideal for industrial applications. In addition, VME supports PMCs for modular I/O as well, offering system designers rich alternatives when it comes to communication. The wide temperature range also makes VME a good fit for remote applications.