RTX The Right Form Factor for Your Rugged Applications

June 25, 2006 Version 1.1
RTX: The Right Form
Factor for Your Rugged
Applications
Author: Claus Giebert
E-mail: claus.giebert@advantech.de
www.advantech.com

June 25, 2006 Version 1.1
Table of Contents
Selecting the Right Form-Factor for Rugged Applications Page 1
Effects of environment of performance, reliability, and longevity of systems Page 1
Considerations for Selecting a Module for Rugged Applications Page 2
RTX Open Standard Form-Factor for Rugged Applications Page 4
RTX Modules for Advantech Page 5
Summary Page 6
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Selecting the Right Form-Factor Module Rugged Applications
The presence of high-end electronic equipment is increasing in many applications including transportation, industrial,
agricultural and power equipment. These applications are expected to operate reliably for several years and are often
subject to harsh environments like vibration, dust, and extreme weather conditions. They need special design
considerations and use of boards and components qualified to work reliably in harsh conditions. The figure below
summarizes the stresses that must be endured in rugged applications.
Figure 1: Environmental stresses in applications that require rugged systems
Effects of environment of performance, reliability, and longevity of systems include:
Extreme temperature conditions: Variations in temperature cause components to contract or
expand. These changes can cause structural changes and impact performance.
Components selected should be able to withstand these variations while still maintaining the
intended performance.
Vibration/shock: Applications on the move must need special protection against vibration and
shock caused by movement. Engine vibration, sudden braking, bumps in the road,
turbulence in the air or water all cause significant forces that cause mechanical failures
Humidity and liquid exposure: High humidity conditions or rain, snow, and fog can be
corrosive and can affect performance or break systems. Also, moisture can exasperate the
effects of temperature or pressure. Outdoor applications are especially susceptible to these
impacts.
Dust, dirt, sand: Solid contaminants like dust are abrasive. A build-up of dust and sand can
insulate components and make them prone to overheating. When combined with water,
they can cause electrical shorts between components.
Pressure: High altitude applications like airplanes and transportation systems must operate
reliably in a wider range of temperature and pressure variations. The main issues with low
pressure are cooling, isolation and certain components like rotating drive disks will fail. This
impacts the needed heatsinks and airflow on cooling, type of components used and the
creeping distances on Ethernet and power supplies.
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The design process for building a rugged system to withstand the environmental stresses mentioned above is extensive.
It involves proper selection of components, connector type and design, PCB layout, materials used, thermal
management solutions, enclosure design, manufacturing process and testing for long-term reliability.
This article helps readers select the right form-factor for processor modules for harsh applications. Using a modular
design approach (module + base-board/carrier board) is gaining popularity in long-life embedded systems. Benefits
include cost and design time reduction, and customization capabilities while taking advantage of off-the-shelf processor
modules available with core functionality. The following sections outline considerations for selecting the right module
for rugged applications, compare several form-factor standards of CPU modules and introduce a new form-factor -
Ruggedized Technology eXtended (RTX) - designed specifically for rugged applications.
Considerations for Selecting a Module for Rugged Applications
Many module solutions are available in the market today. Advantech itself offers solutions based on COM-Express
Basic, COM-Express Compact, COM-Express Mini, ETX, Qseven, RTX and SMARC form factors. Each of these
form-factors is designed with specific applications and some are more suitable for rugged applications than others.
This section outlines considerations for selecting the right module for rugged applications.
Extended temperature support–One of the first considerations is the range of temperature
the system can tolerate. For applications built for outdoor use, the hardware should be able
to operate reliably in very high and low temperatures. Most commercial solutions offer
support from 0 0 C to 60 0 C. This range is unsuitable for operation in sub-freezing conditions
and should not be considered for rugged applications. Temperature specification for rugged
applications should be at least -40 0 C to 85 0 C. This means that all components – chips, PCB
material, connectors, etc. should withstand this range and maintain functionality.
PCB thickness–Some vendors offer boards with thicker PCB fabrication so they can withstand
higher levels of vibration. Thicker PCBs offer greater stability and protect from damage due
to vibration. They also provide the option of having more layers and/or thicker cooper per
layer to improve thermal performance and heat/cold dissipation capabilities. This is
important as cooling fans and heat sinks are not practical in applications “on the move”.
PCB material and protection mechanisms from corrosive elements – Moisture, condensation
due to temperature gradients, dust, and chemicals corrode the surface of the PCB and cause
electric failures. To protect against these elements, PCBs should have conformal coating.
Coating materials used (acrylic, polyurethane, epoxy, or silicone) and application methods
(brushing, spraying, or dipping) will depend on the application and its requirements.
Connector type and setup – Processor modules are typically connected to the base board via
PCB connectors. Choice and set up of connectors is important as the impact of vibration
directly affects the quality of connections between pins on the module and the base-board.
A poor connection will cause a voltage drop or even result in degradation of signal quality up
to complete connection fail. Connectors should have strong mating force and strong contact
holding force to resist being pulled apart, and contain large contact surfaces to provide
adequate support in heavy vibration environments.
The figure below shows the connector type setup of popular module form-factors.
Qseven have the MXM type connector typically used in commercial applications.
Smarc and
Smarc, Qseven,
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and Com Express Mini all have one connector. RTX has four symmetrically laid out connectors to
increase stability and increase the surface area of contact.
Figure 2:
Connector Type and Setup Comparisons in Various Modules
Input voltage range–Transportation systems like trucks, agricultural vehicles, campers and
recreational vehicles require support for 24V input voltage. On the other hand, there are
instances like sensor applications, when 5V support is required. Selecting offerings with a
wide range will improve design flexibility and provide scalable solutions for a range of offerings.
A suitable voltage range can easily be selected based on overall system requirements.
Communication interfaces and latency requirements–Bandwidth and latency requirements
coupled with the type of interfaces needed for the application must be considered. Module
makers offer a choice between high-speed serial interfaces or lower speed parallel interfaces.
Both options have trade-offs relating to total bandwidth, the number of pinouts available,
maximum transmit distance and latency. Where transmit distance is longer or the number of
pinouts is limited, serial interfaces work best. In applications where latency is a concern,
parallel interfaces perform better. For serial interfaces, data transmitted is serialized at the
transmitter and then de-serialized at the receiver. This process increases latency as it
requires additional clock cycles. Parallel interfaces do not require the
serialization/de-serialization process and are better suited for low-latency applications.
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RTX Open Standard Form-Factor for Rugged Applications
To address the module requirements for rugged applications discussed in the preceding section, Advantech, AAEON,
and Avalue collaborated to build an open standard rugged form factor - RTX (Rugged Technology eXtended).
Features of the RTX form factor include:
Compact size (68mm x 68mm) to make it suitable for many rugged applications
2.0mm PCB thickness along with conformal coating to protect against vibration, moisture, dust,
humidity, etc.
Wide temperature (-40 0 C to 85 0 C) for many operating environments and outdoor applications
Four board-to-board connectors to offer solid anti-shock and anti-vibration capabilities
Wide input range (5V to 24V) to support several applications including many transportation
systems that require 24V support
400-pin I/O with standard PC-type interfaces for direct access to the parallel system bus (ideal
for low-latency applications)
Figure 3: Module Based on RTX Form-Factor and Connector Definitions
The chart below summarizes the key differences between RTX and other module standards. It highlights the
advantage of RTX for rugged applications.
Table 1: Comparing RTX with other popular standards
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The RTX website has more information the standard and specifications and design guides for download.
RTX Modules for Advantech
Advantech offers RTX 2.0 modules based on NXP’s i.MX6 and TI’s AM3352 processors. To enable quick prototyping,
evaluation carrier board for easy integration and hardware design reference (part #: ROM-DB3900) are provided for
both modules. In addition, a Linux BSP utility and reference codes for application development and device integration
are provided. The ROM-3420, based on NXP’s ARM Cortex-A9 processor, has these features
• NXP’s ARM Cortex-A9 i.MX6 dual core
• On-board DDR3 1 GB memory / 4GB flash
• OpenGL ES 2.0 and OpenVG 1.1 hardware accelerators
• Full HD 1080p video decode and HD 1080p video encode hardware engine
• 1 PCIe, 1 GBE, 1 USB2.0 , 1 USB OTG2.0 , 1 SATAII, 4 I 2 C , 1 I 2 S, 1 Camera in, 2
CANbus, 10 GPIO
• Linux and Android BSP
This URL has a complete listing of all RTX solutions from Advantech.
Figure 4: RTX 2.0 Module based on NXP’s i.MX Processor
RTX Starter Kit for Quick Evaluation and Product Development
Advantech offers a starter kit for RTX to help engineers minimize product evaluation and development time. The
ROM-3420 Starter Kit integrates pre-verified hardware, software, and sample code needed to set up the system for
evaluation.
The ROM-3420 Starter Kit includes:
• Main board – RTX v2.0 ROM-3420 & ROM-DB3900
• LCD kit – 7" LED PANEL 400N 800X480 and cables
• I/O board – Debug, Audio, PCIe, I2C, SPI, System
Bus boards
• Cable – Console, SATA, RS-232, USB, Audio cables.
• Adapter – A/D 100-240V 19V 65W
Summary
Figure 5: Development kit for RTX Module
ROM-3420
It may be tempting to buy commercial grade equipment due to low initial investment. However, this decision will
increase the total cost of ownership due to field failures, system shut downs, replacement and deployments costs.
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Applying design best practices and using modules, boards and components qualified for rugged applications will
dramatically improve product quality and lifespan of the device.
RTX is a new open standard form-factor specifically designed for applications exposed to shock, vibrations, and the
environmental elements. Designed with extended temperature support, strong connector setup, thick PCB and wide
input voltage, RTX was specifically designed for rugged conditions. OEMs can benefit from Advantech’s RTX
off-the-shelf modules and expertise in building systems for rugged applications.
References
Designing Rugged, Standards-Based Embedded Solutions
COM Express mini, Qseven, SMARC meet at the crossroads of an evolving processor landscape
Managing the Effects of Heat, Dust, and Vibration on a GPS Receiver in a Desert Environment
When Transportation Applications Get Rugged
Failure of electronic components
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