Single-board Computers Widely Applied

The single-board computer (SBC) has its roots in the need for application-specific computing power in the control industry. Early designs go back 20 years or more. And although the designs were often based on the idea that an SBC could be just that—a single-board device—board-level component size, power requirements, and the need for expanding systems options often made SBCs only ...

By Dick Johnson, CONTROL ENGINEERING September 1, 2003


From optional to essential

Low cost reliability


Power upgrades

The single-board computer (SBC) has its roots in the need for application-specific computing power in the control industry. Early designs go back 20 years or more. And although the designs were often based on the idea that an SBC could be just that—a single- board device—board-level component size, power requirements, and the need for expanding systems options often made SBCs only a building block in each system.

Over the years, as the SBC market evolved, so did the SBC. System architecture and form factor standards evolved. On-board computer power and functionality improved. Commercial off-the-shelf (COTS) devices supplanted purpose-built boards and use in a wide variety of control applications became commonplace.

To access trends in this industry sector, Control Engineering and Reed Research Group polled subscribers about their SBC preferences in an e-mail survey. Complete responses were received from 182 subscribers who specify, recommend, or purchase SBCs for in-plant or OEM requirements.

Applications for SBCs within the control function appeared in all areas. The accompanying diagram illustrates the range of applications where SBCs are used. With the exception of bothcontinuousandbatch processingapplications, which garnered the most responses, use is evenly spread among discrete manufacturing, continuous processing, and theutilitiesindustries.

Top of wish list

Survey participants were also asked to identify the most important features required in the SBCs they ultimately purchased. Although a wide variety of application-specific requirements were mentioned, a number of general requirements topped the list. These included in descending order: reliability/dependability, cost (and related issues), ruggedness, and computing speed. Ease of use was also of concern to respondents.

According to David Pepper, director of engineering, embedded systems, at GE Fanuc Automation Americas Inc., “Single-board computers are so widely applied that reliability is no longer optional, it is essential.” SBCs can be found in everything from industrial control systems to medical diagnostic equipment to sophisticated military equipment. Because of this, the SBC has become an essential building block of control reliability and the subject of intense quality control practices over the years.

As a result, advanced quality-control programs have been widely adopted throughout the SBC industry. Various industry and trade associations have defined standards in SBC design and manufacturing to increase reliability. Standard features introduced over the years that have increased reliability include watchdog timers with reset, enhanced bus error handling capability, passive heat sink design, multiple power supplies for redundant operation, hot-swap capability, use of conformal coatings for extended temperature operations (part of the sought-after ruggedness feature as well), and redundant array of independent disks (RAID) for handling hard-disk crashes.

Controlling costs

Shrinking business in many sectors has made the SBC market extremely competitive over the past few years, placing great pressure on unit cost of many products as sales volumes decline. Product development investment has been affected and budgets slashed, forcing managers to meet project schedules with fewer people and resources.

To manage costs and hold down SBC prices, the industry has responded in several ways. According to Greg Novak, product manager at Motorola Computer Group, “Many proprietary, single-source, custom-processor solutions are available from numerous OEMs. Many vendors offer one and even multiple solutions. Standardization drives down cost …[and] increases sales volume. Additionally, at Motorola and generally throughout the industry, commodity-based quality embedded parts are used whenever possible to control costs.”

Decreasing time to market has also had a positive effect on SBC cost. Leveraging CAD layout techniques, managing schematic complexity, and decreasing debug time has given the SBC industry the ability to produce a broad array of products quickly at affordable prices.

Inhospitable environments

The more adaptable a device, the more likely it is to encounter less-than-perfect working conditions. Industrial environments are home to harsh conditions, including high- and low-operating temperatures, radio frequency and electromechanical interference, vibration, corrosive atmospheres, dust, and dirt. Providing the ruggedness demanded by survey respondents requires providing design safeguards for these conditions.

Thomas Chou, product manager at Advantech Technologies Inc., suggests that even though products are tested in compliance with IEC standards for high/low temperature operation, vibration and shock resistance, electrostatic discharge, and boot-up performance, ruggedness testing must go beyond these to provide quality SBC devices. Chou says that true operational ruggedness must pay special attention to three essential areas: “design, material, and testing.” According to Chou, “Good design includes elimination of cross talk by taking into account the impedance and interference between traces and layers of the printed circuit board. Also, temperature simulation and power distribution analysis must be done to ensure quality design.”

Quality material must include parts (integrated circuits and other board-level components) that ensure performance across a wide range of operating temperatures. Finally, printed circuit board materials must be specified and manufactured so that board defects, such as cold soldering in the wave tank are eliminated and joint conductivity maximized.

The future of SBCs

“Commercial off-the-shelf SBCs offer a tremendous advantage over custom solutions,” says George Renth, VP, operations at SMA Computers. “Processing power can be upgraded with a simple CPU change and development costs spread over many customers and applications. The downside is that COTS devices may not have the particular functionality an application requires or may have costly features a customer does not need. They do meet the ‘quality niche’ where the volume does not warrant a custom solution.”

Use of SBCs in industrial control applications will expand as factories demand further productivity increases and greater connectivity between resources. Renth adds, “Technology key to this expansion is the increasing use of CPU cores of differing architectures with various mezzanine options. This solution will continue to provide scalable CPU power and application-specific expansion, but without the additional cost of custom development and unneeded features.”

Even though the operational requirements of potential single-board computer users may be diverse, their most pressing concerns seem to be with the SBC industry. The bead is carefully drawn, meaning that the clear winners of this “marksmanship” competition will be the control engineers that use the devices.

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SBC products

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Small footprint, more power

Advantech Co. Ltd. offers two new RISC platforms (PCM-7220 and -7320) said to help users target low power/space-critical applications by offering more power and expansion flexibility on a 2.5-in. footprint. Platforms are based on the Intel Xscale (PCM-7220) and Samsung ARM9 (PCM-7320) processors, respectively. PCM-7220 is a 2.5-in. Biscuit SBX with an Intel RISC Xscale PXA-250 processor running Microsoft Windows CE.Net or embedded Linux. PCM-7320 is a more cost-effective application-ready board integrating Samsung’s ARM9 S3C2410 System on Chip in a comparable form factor. Both are designed to offer users a fast time-to-market and a customizable and flexible reference platform. Advantech Embedded Computing

Low-cost control

OEM2500 Coyote single-board computer provides OEM designers low-cost embedded control for high-volume applications. Two standard models are available—one with Ethernet, one without. Starting at $69 and $99, it offers multiple options for built-to-suit custom orders to lower OEM product costs. In volume orders, it can match user-specified configurations. Various feature combinations are available for memory, 10Base-T or 10/100Base-T Ethernet, digital I/O points, serial ports, LEDs and onboard backup battery. Coyote features the Rabbit 3000 microprocessor at 29.4 MHz, 256K Flash and 128K SRAM, 5 serial ports, 16 rugged I/O points (plus 1 A/D input and 2 D/A outputs), 4 LEDs, and 10 timers. It is designed for control and data acquisition applications. Z-World Engineering Inc.

High-performance levels

Kontron’s ETX-P3M component SBC supports the Mobile Intel Pentium III Processor-M and Celeron processors (650 and 933 MHz processors with long-term availability and up to 1.2 GHz processors in socketed versions). Reduced power consumption is achieved using ACPI and APM 1.2 for power management. With an integrated core chipset, the device provides Pro Savage 4 graphics and enhanced audio. In addition to standard ETX features, the ETX-P3M supports four USB ports, up to 1 GB-SDRAM, 10/100Base-T Ethernet, keyboard/mouse controllers, real-time clock, and watchdog timer. Kontron

Remote device management

VSBC-8 SBC now supports remote boot management firmware from Argon Technology, allowing users to remotely manage client devices. It is also available in extended temperature and low-power versions. EBX-compliant board comes in three versions: Intel Pentium III 850 MHz, extended temperature (-40 to 185 °F) with a Celeron 350 MHz, and low power with a fanless 350 MHz Celeron CPU. Features include PC/104-Plus expansion, AGP video/flat panel, 10/100 Ethernet, and up to 256MB SDRAM. Industrial features include Opto 22-compatible digital I/O devices, four COM ports, and three extra timer/counters. VersaLogic Corp.

More processing power

PrPMC610 low-power processor PMC module provides up to 40% more processing power than its predecessor. Single-width PMC (PCI Mezzanine Card) module is powered by a PowerPC architecture processor, the MPC8245. The processor is supported by up to 128 MB on-board Error Correcting Code (ECC) SDRAM with the option for an additional 256 MB memory expansion and 9 MB on-board flash. . Motorola Computer Div.

SBC for harsh applications

WinSystems EBC-LP Intel 166 MHz Intel Pentium “Tillamook”-based SBC is intended to meet the demand of embedded system designers for a fast, integrated hardware and software solution for harsh industrial applications. The device has an operational temperature range from -40 to 185 °F and is preloaded with the Microsoft Windows CE.Net operating system. Its integrated, end-to-end tool set and familiar programming environment are said to reduce system and application development times. WinSystems

High-speed Xeon processor

Compact SBC-F9000V2G single-board computer is designed to support mission-critical, high-speed telecom, and ISP applications. It uses Intel’s E7500 or E7501 Xeon Processor, 1.8G to 2.8 GHz+ with Hyper-Threading technology. Device is designed around an mPGA604 ZIF CPU socket and features a supporting bus frequency of 400 MHz or 533 MHz, depending on the chipset in use. It is a full-size CPU card, measuring 13.3 x 4.8 in. Arista Corp.

Additional Online Products

Dual processor VMEbus SBC

VG5 joins the SBS Technologies’ family of high-performance 6U VMEbus single-board computers. Configured with dual processors, VG5 reportedly delivers the speed and bandwidth for real-time control, post video processing, and signal-processing subsystems. VG5 is offered with a choice of one or two integrated 800-1,300 MHz Motorola MPC7455/57 PowerPC processors featuring AltiVec technology. Integrated design permits two computing platforms in one slot. Because each processor has its own memory and chipset, one processor can number crunch DSP tasks while the other works as a general-purpose CBE and facilitates board I/O functions. SBS Technologies Inc.

Single-slot low voltage board

VMICPCI-7761 is a low-voltage Intel Pentium III processor-based single-board computer for CompactPCI applications. It features a low-voltage processor with 512 KB advanced transfer cache. Processor speed is up to 933 MHz. The SBC delivers high bandwidth while heat dissipation is kept at a minimum. On-board memory is provided by up to 1 GB PC1133 registered ECC DIMM, and an option for CompactFlash storage is attached to the secondary IDE interface. Fully compliant with the PICMG open standards specifications, the device operates as either the system controller or peripheral controller and is hot-swappable. Operating system support includes Microsoft Windows NT/2000, Linux, and Wind River’s VxWorks. GE Fanuc Automation Americas Inc.

Compatible with previous versions

3U Compact PCI CPU6.2 or Compact MAX maintains its form factor and internal functioning of its watchdog, voltage monitoring, SRAM, and CompactFlash units, making it 100% compatible with the previous SBC version. According to its developer, performance has been enhanced by increasing the main memory to range from 128MB to 1GB, allowing users a choice of Intel Pentium III or low power VIA-C3 CPU options, increasing the front side bus rate from 100 to 133 MHz, and providing dual Ethernet capability. Its 3U form factor makes it suitable for a wide variety of industrial applications. SMA Computers

High-performance all-in-one board

Broadax Systems offers a variety of single-board computers that include both half- and full-size boards running on Socket 478, Socket 370, and Socket 7. These systems, which include the new SBC-9648E, provide either single- or dual-processor power and offer Intel and VIA chipsets. For example, the SBC-9648E is an AGP Bus, full-size Intel Pentium SBC that allows for up to 3.06 GHz processing and up to 2 GB DDRMM, which are said to provide more power than existing SBCs can deliver. The all-in-one computer board is designed for computer and graphics-intensive applications, such as scanner displays and industrial workstations. Broadax Systems

Low-power consumption

STX88600VEA low-power consumption all-in-one System On Module joins a line of STX modules in a PC/104 form factor (3.6 in. x 3.8 in.) and attaches to standard or customized baseboards. The baseboard works as the input/output for the STX module. Device features a VIA C3 EBGA processor (available at different speeds) with a VIA VT8606 (Twister-T) chipset and a VT82C686B Core Logic controller. Its S3 Savage4 AGP-4x video controller is integrated into the chipset, has a 128-bit 2D/3D graphics engine, and supports CRT and LCD devices with a maximum of 32 MB memory. Other features include a Realtek 8139C/C+ PCI PnP 10/100 BaseT Ethernet port with Wake On LAN support, an IDE controller that supports up to two devices, one 144-pin ECC SODIMM socket for up to 512 MB SDRAM, two USB ports, an ac-link for audio support via the Baseboard. Axiomtek

Data acquisition capability

DT9841 Fulcrum II Series combines the accuracy ofTexas Instruments’ floating-point TMS3206711 digital signal processor with thespeed of two 24-bit sigma-delta A/D and D/A converters on a standads 6U card. Intelligent data acquisition system for processing real-time measurements communicates to the host via USB 2.0. Standard design is a single 6U card with connections for analog input, analog output, trigger, and clock. Data Translation