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The Agilent Virtual Rack Platform: Reducing the Effort, Complexity and Cost of Test System Creation, Revision and Deployment


September 18, 2007

Automated Test Systems (ATS) utilized in aerospace and defense applications today pose a daunting challenge in terms of the time and effort required for integration, automation, maintenance and evolution. In response to the military's growing need to reduce operational costs, ATS cost has also become an issue, forcing many contractors to focus on lowering the overall lifecycle costs of test platforms. The difficulty of this challenge is often compounded by the need to sustain test systems over the multi-decade (e.g., 20 to 30-year) life of the supported platform—a need that typically increases the long-term maintenance costs of an aging automatic test system. As system requirements become more complex, these challenges often leave users of previous-generation tools stuck inside a maze of complexity.

While existing test system architectures should ideally help mitigate these challenges, they often fail to offer the reduction in time, effort and cost that today's ATS developers demand. Worse yet, their shortcomings only exacerbate the problem. What's required is a new alternative for creating flexible test system frameworks - one that addresses the shortcomings of existing architectures through an interactive platform which dramatically reduces effort across the integration, automation, maintenance and evolution of test systems; and at the same time, produces radically better results. With this approach, military services, defense contractors and aerospace companies can now obtain the test-system longevity they demand, while being free to focus their efforts on their domain expertise.

Existing Challenges

The challenges facing developers of ATS for use in aerospace and defense applications are made all the more complex by the typical approaches to test-system architecture and integration. Most test-system architectures, for example, generally require standardized instrument interfaces or communication protocols that directly couple hardware devices to software. As a result, satisfying a set of test requirements often requires moderate to significant levels of customization, further lengthening development time and making system testing more difficult. It also generally requires that a variety of different instrument types (e.g., PXI cardcage, LXI-based instruments or rack-mountable bench-type instruments) be used. Unfortunately though, each piece of system hardware may have a different option for I/O and each increase in the number and type of I/O directly increases system complexity. Use of one application or language for the test system software can also be problematic as it forces compromises in terms of functionality, performance and ease of use.

FIGURE 1: The complexity of traditional test systems begins with the star pattern of interconnection

FIGURE 1: The complexity of traditional test systems begins with the star pattern of interconnection.


Perhaps the biggest contributor to ATS complexity though, is the use of star-shaped architectures in which every system connection and protocol conversion must be uniquely programmed (see Figure 1). As a result, a change in one system element requires changes in every other connected element. Further adding to the complexity, this architecture requires developers to follow a lengthy, set sequence of steps when integrating and automating a system. What's more, as the star-structured ATS ages, it becomes increasingly difficult to migrate from old to new instrumentation, I/O interfaces, software or communications protocols. Here software is the biggest problem, since virtually 60 percent of all test-routine code that controls the interfaces between devices and software must be written from scratch each time an instrument is changed - whether due to an upgrade or the instrument simply being offline for repair or discontinued. This is a costly and time-consuming process often requiring re-qualification of the ATS.

Because of these shortcomings, developers are typically forced to employ their own tactics to gain the benefits they need. For example, to:

  • Simplify integration - developers integrate using multiple programming tools and protocol
  • Accelerate automation - developers use programming to implement automation based on input from the DUT expert.
  • Optimize maintenance - developers design, program, test, and validate each connection and optimization.
  • Extend longevity - developers change test-system specifications, redesign with new hardware, or rewrite old programs in a new version or language.

Effectively eliminating the shortcomings of existing architectures - as well as the overall complexity of ATS creation, revision and deployment - requires an approach that can easily deliver these benefits, while at the same time providing developers with the ability to focus on their core area of expertise.

A New Alternative

The Agilent Virtual Rack platform offers a new, interactive approach to addressing the needs of developers creating, revising and deploying ATS for aerospace and defense applications. Delivering reusability, flexibility and robustness without sacrificing performance, it offers developers an order-of-magnitude reduction in the effort associated with designing, integrating, automating, maintaining and evolving their physical system.

Agilent's Virtual Rack platform family is comprised of three key products:

  • Virtual Rack Platform 7.8: One node-locked computer license to operate hardware, software, firmware and services components mounted and configured by Virtual Rack Integrator.
  • Virtual Rack Integrator 7.8: Enables the user to connect, operate, automate and extend hardware, software, firmware and services within a test system.
  • Virtual Rack Modules: Enable creation of flexible Virtual Rack frameworks from Virtual Rack Platforms. Currently available Virtual Rack Modules enable networking, telemetry, mnemonics, MIL-STD-1553, FPGA, GPS synchronization, battery string simulation and solar-array simulation.

Using the Virtual Rack platform, developers can build new test systems or modify existing ones. Virtual Rack frameworks expand these platform capabilities by adding flexible Virtual Rack Extensions. Applications are then built atop frameworks to address specific testing needs.

How It Works

In contrast to test-system architectures that require standardized hardware, software, instrument interfaces or communication protocols, the Virtual Rack platform relies on a services-based approach to enable inclusion of a wide range of languages, drivers, interfaces, protocols, test executives and instrument types into hybrid systems that easily combine new and existing elements. Key to this approach is the intuitive Agilent Virtual Rack “storeroom” concept which houses thousands of hardware, software and firmware components from Agilent, as well as numerous other vendors. Agilent “interactor” technology is used to transform the complex programming tasks and behaviors into configurable services. All storeroom elements are accessible through an efficient, Web-like interface that enables easy drag-and-drop test system creation, modification or system element replacement.

To mitigate instrument or software obsolescence, the Virtual Rack platform decouples all system elements (e.g., instrumentation, I/O and software) within a matrix-based architecture, replacing programming for system integration with configuring components and services (see Figure 2). Integration therefore, is independent of specific interfaces or programming languages, instead being defined through an interactive matrix. The developer must specify only the endpoints—instruments, I/O, software, protocols. The VR platform then handles all of the communications and translations required for integration and automation. Consequently, when an instrument must be replaced, it can be hot-swapped by changing the connections even if its predecessor used a different communication protocol.

FIGURE 2: The matrix-based architecture employed by the Virtual Rack platform allows the desired state of integration to be easily defined via an interactive matrix.

FIGURE 2: The matrix-based architecture employed by the Virtual Rack platform allows the desired state of integration to be easily defined via an interactive matrix.


Whereas instrumentation based on a star-shaped architecture can take months to integrate and years to automate, the Virtual Rack platform with its matrix-based architecture enables integration in a matter of minutes and automation in hours. In part, that's because the Virtual Rack platform enables test system creation in just four steps, and using the developer's language of choice for custom behavior.

The Virtual Rack Explorer is the Graphical User Interface (GUI) of the Virtual Rack Platform. A test system can easily be created using the four step Virtual Rack MORE process (Mount, Operate, Record and Extend). Firstly, components are mounted into a Virtual Rack framework using a mouse to drag and drop elements housed in the storeroom and foreign protocols are automatically translated and connected to the Virtual Rack matrix. Operation can then begin using the Operate button where a tree view of the capabilites of the components mounted are displayed. User definable panels can also be created with Virtual Rack Forms. Next, the Virtual Rack Macro Recorder creates automated sequences and tests. And lastly, new capabilities can be added to the system as necessary using the Extend button, with drag and drop simplicity - and without modifying original components.

FIGURE 3: Virtual Rack Explorer is used to view, operate, manage and integrate a measurement system.

FIGURE 3: Virtual Rack Explorer is used to view, operate, manage and integrate a measurement system.


For the developer, the simplicity of this approach allows the realization of four key benefits:

  • Simplified Integration: A drag-and-drop capability connects favorite hardware, software and firmware.
  • Accelerated Automation: Virtual Rack automates (records sequences) as the developer browses; targeting output to the developer's language or test executive.
  • Optimized Maintenance: Modifies system components and connections on the fly.
  • Extended Longevity: Easily adds capabilities and hot swap hardware and software to modify old functionality.


Utilization of the Virtual Rack platform offers an efficient, interactive means of creating flexible system frameworks, while significantly reducing the time and effort required to integrate, automate, maintain and evolve test systems; and delivers radical results. Its an order-of-magnitude reduction in effort that allows developers to fully focus on their domain expertise, rather than on how to deal with the test system complexity and clutter. Test systems created with the Virtual Rack framework not only help extend the life of existing test assets, but once deployed can help protect the ATS against obsolescence by greatly simplifying the process of replacing an instrument, software application, I/O connection or communications protocol. As a result, creating and deploying automated test systems for use in aerospace and defense applications has never been easier.

About Agilent
Agilent Technologies Inc. (NYSE: A) is the world's premier measurement company and a technology leader in communications, electronics, life sciences and chemical analysis. The company's 19,000 employees serve customers in more than 110 countries. Agilent had net revenue of $5.0 billion in fiscal 2006. Information about Agilent is available on the Web at www.agilent.com.



Janet Smith, Agilent
+1 970 679 5397

Related links for more information
  Press Release: Agilent Technologies Launches Platform for Effort-Saving Test-System Creation, Deployment in Aerospace/Defense Applications
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