Defining Open Standards: An Introduction to OpenVPX

In both defence and industrial applications, the demands on embedded computing systems continue to grow. These applications do not just need raw computing power; they need systems that will remain supportable and upgradeable for decades. This is where open standards like OpenVPX play a crucial role, ensuring long-term availability and interoperability of critical system components.

Core Principles of OpenVPX

OpenVPX, formally known as VITA 65, builds upon the base VPX standard (VITA 46) to define system-level interoperability for multi-vendor, integrated systems. While VPX establishes the fundamental specifications for boards and backplanes, OpenVPX provides the framework necessary for true system integration. Specifically, it defines interoperability across three critical interfaces:

  • Module-to-module communication
  • Module-to-backplane connections
  • Chassis integration requirements

OpenVPX organises system communications into distinct planes, each serving a specific purpose in the overall system architecture:

  • Utility Plane for power distribution and basic system functions
  • Management Plane for system monitoring, control, and health status
  • Control Plane for command processing and system configuration
  • Data Plane for high-speed information transfer between processing elements
  • Expansion Plane for specialised interfaces and system-specific needs

To support these planes, OpenVPX defines various communication pipe sizes—including the Ultra-Thin Pipe, Thin Pipe, and Fat Pipe, ranging from low-bandwidth control signals to high-speed data transfers.

For I/O expansion, OpenVPX supports both XMC (VITA 42) and FMC (VITA 57) Mezzanine Cards, offering different approaches to adding specialised I/O capabilities:

  • XMC (VITA42) (Switched Mezzanine Card) modules typically interface through PCI Express or other serial protocols, making them ideal for high-speed data processing applications.

Figure 1: XMC mezzanine card with digital signal processor (DSP) unit. (Image source: Sundance Multiprocessor Technology)

  • FMC (VITA 57) (FPGA Mezzanine Card) modules provide direct connection to FPGA I/O pins, allowing for more customised and lower-latency I/O implementations.

 

Figure 2: The Sundance Multiprocessor FMC module family. (Image source: Sundance Multiprocessor Technology)

Although the OpenVPX specification is thorough and detailed, it is also highly modular. This modularity simplifies system integration straightforward because engineers can focus on just the sections relevant to their specific needs rather than having to understand the entire standard at once.

 

Benefits of the OpenVPX Approach

OpenVPX offers several key advantages that make it particularly valuable for aerospace, defence, and industrial applications:

  • Modularity: The standard defines specific Slot, Module, and Backplane Profiles that detail available functions and interfaces. This level of definition ensures components can operate together reliably.
  • Flexibility: Systems can be configured with widely varying combinations of processing, memory, and I/O resources needed for each application. Multiple form factors and cooling options provide additional design flexibility.
  • Robustness: The standard is optimized for extreme environments, with extensions like VITA 48 (VPX REDI) addressing specific cooling requirements.
  • Future-Proof: OpenVPX supports modern high-speed interfaces including 10/40/100 Gbit Ethernet, PCIe Gen 4/5 and other serial connections, while maintaining a framework that can adapt to future technologies.

In the defence sector, these characteristics allow OpenVPX to deliver the processing power for modern military capabilities including Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR), Signals Intelligence (SIGINT), and electronic warfare applications, all while ensuring reliably in harsh environments.

Harsh environments also include aerospace. VITA has introduced the SpaceVPX standard (VITA78) to support modern aerospace applications. It defines a highly reliable system architecture that meets the special requirements of satellites and other space-qualified systems. The standard places a strong focus on radiation safety, redundancy, and reliability.

In industrial infrastructure, OpenVPX systems support the growing need for edge computing and AI-driven applications like predictive maintenance. The standard’s emphasis on long-term sustainability makes it particularly valuable for critical infrastructure deployments.

 

How OpenVPX Compares with Other Standards

While there are many embedded computing standards targeting these markets, OpenVPX differs in its approach to integration. Many other standards focus on specific aspects of system design but do not provide OpenVPX’s comprehensive framework for system-level integration.

For example, PXIe and CompactPCI are 3U card standards primarily focus on board-level interconnects and basic electrical specifications. While widely used in commercial applications, they lack OpenVPX’s extensive provisions for system-level integration, ruggedization, and specialized military/aerospace interfaces.

COM Express and PC/104 are another example. This standard defines computer-on-module specifications but addresses a limited set of communication protocols, making these modules more like a building block for a system. In contrast, OpenVPX incorporates a wide range of interfaces, backplanes, power supplies, and racks—and hence provides more comprehensive system integration guidelines.

Figure 3: The VF360 is an OpenVPX slot card with an Altera FPGA and TI DSP (Image source: Sundance Multiprocessor Technology)

 

OpenVPX in Critical Infrastructure: A Case Study in Global Energy Innovation

A common misconception about OpenVPX is that it is only for defence applications. In reality, it extends well beyond that, as demonstrated by one of the global leaders in energy through their deployment of High Voltage Direct Current (HVDC) systems. These systems, designed to transmit electricity over long distances with minimal energy loss, utilise the Etion Create VF360, a 3U OpenVPX module, to achieve exceptional performance and efficiency. Unlike traditional Alternating Current (AC) systems, HVDC uses direct current, which allows for more efficient and stable power transmission. This is especially beneficial when integrating renewable energy sources, such as offshore wind farms, into the main power grid.

For more information and updates on HCDV projects worldwide, visit https://hvdcworld.com.

Figure 4: 10 cards of VF360 are used in the system, controlling the converter stations in a current HVDC project. (Image source: Aquind and Sundance Multiprocessor Technology)

The VF360’s combines the Altera Stratix V FPGA and Texas Instruments KeyStone Multicore DSP technology to provide the ultra-high-bandwidth processing needed for these advanced grid control features. Equally important, OpenVPX’s emphasis on long-term sustainability makes it ideal for critical infrastructure applications where systems must operate reliably for decades.

This application showcases how OpenVPX’s combination of high performance and robust standardisation can benefit both defence and industrial systems. By providing a stable, well-defined framework for system integration while supporting modern high-speed interfaces, OpenVPX continues to prove its value in the most demanding applications.