VITA 47, environmentally sound
The standards developed by the members of the VITA Standards Organization typically fall into one of two categories. The first are hardware standards, which define the hardware parameters for some type of form factor, interconnection, or other mechanical features such as cooling. Hardware supplier companies that have expertise in a specific aspect of that technology typically leads the creation of hardware standards, while the user community provides inputs guided by their real-life design experiences.
The second category is difficult to classify, but ability is probably the best term. These standards focus on the “abilities” with examples including reliability, interoperability, etc. They also define the operating environments and life cycle management strategies necessary for defined applications. They tend to be living documents or dynamic documents that undergo refinements while having long applicability life spans. Another interesting aspect of this class of standards is that members of the user community usually lead the development with inputs from the supplier side participants.
ANSI/VITA 47, Environments, Design and Construction, Safety, and Quality for Plug-In Units is one of the standards in the ability category. This standard defines environmental, design and construction, safety, and quality requirements for commercial-off-the-shelf (COTS) plug-in units (cards, modules, etc.) intended for mobile applications. Modules certified to a specific environmental class meet the corresponding operating temperature class, non-operating temperature class, temperature cycling class, vibration class, and operating shock class. Suppliers are encouraged to indicate this compliance in their documentation so that it is easier and faster for users to determine if a specific product will meet their environmental requirements. This enables users to verify a specific plug-in module is applicable to a specific application and will result in the desired system reliability.
The industry benefits in multiple ways:
- A better fit between the module design and the application results in improved reliability and durability.
- Better system engineering without reliance on a specific VPX module supplier’s ruggedization guide. There is more consistency in terminology and data across suppliers.
- Improved capability to perform future module upgrades and resolution of obsolescence and maintenance issues.
COTS plug-in units are widely used in commercial and military, ground and aerospace, and mobile applications. Certification of COTS plug-in units, by supplying vendors, to this standard facilitates the cost-effective integration of these items in larger systems.
ANSI/VITA 47 was first published in 2005, but it is now undergoing a major revision. I asked working group chairman Scott Newland from Harris Corp./GCSD: What is driving the effort currently underway? His response, “New Applications. The abstract from the original release states the environments defined were intended for mobile applications. We are finding that VPX products are being applied in applications ranging from submarines to spacecraft and the environments for these different applications are unique, so we need to update the specification accordingly.”
With ten years of usage history under their belt, the user community is also finding that there were some issues with the current standard that makes system engineering challenging, forcing them to rely on specific module suppliers design information. This has made designing for future maintenance or upgrades challenging.
“We are creating a new dot, or sub, structure to allow the addition of new environments and applications as they arise,” Newland comments. The substructure of VITA 47 will look like this:
- The new VITA 47.0 standard contains the current VITA 47 environments to document the heritage applications.
- VITA 47.1 will contain all the “common” environmental requirements.
- VITA 47.2 documents the environments that align with J-STD-001 Class 2 applications for VPX plug-in units with less severe environments and consequence of failure.
- VITA 47.3 documents environments that align with J-STD-001 Class 3 applications for VPX plug-in units with more severe environments and consequences of failure, like airborne uninhabited fighters.
In the future, additional dot standards can be added for emerging applications like space deployment.
When you order a module from a VPX supplier you will specify which VITA 47 dot standard set of environmental conditions you will be implementing in your application. This will enable the supplier to provide you with the information and products you need to meet your project goals.
This is not an easy task. The working group has been diligently “plugging” away for some time on this effort. Newland points out the challenges he is facing as the working group chair, “Finding non-ITAR data to support the selection of the different environments is very difficult. There are 15 current environments: vibration, shock, and more. In VITA 47, we want to add several more including module insertions, minimal retainer performance, and explosive atmosphere.”
He also emphasized that the size of the effort is substantial and very challenging given that he and the other members of the working group also have day jobs! “The overall vision has remained the same, but we have added a lot of valuable information to the effort.”
Plug-in units provided to this standard shall be per one of the classes defined in the following table. (See Table 1).
Anyone interested in participating in this effort should contact VITA: www.vita.com