The first VXIbus specification was introduced to the test and measurement community
in 1987 and was initially developed to provide a card-based instrumentation platform
for applications that required high density and high performance. The platform continues
to thrive today by leveraging off the original specifications which define the necessary
physical (real estate/cooling) and electrical standards for demanding applications
and has established itself as the ‘time-tested bus you can trust’ for requirements
that must be supported in excess of ten-fifteen years.
The systems base for which VXI is optimally designed, in addition to those that
require density and performance, is that which demands the stability over time that
can only be provided by a true instrumentation bus. The VXIbus platform has shown
a remarkable ability to adapt to the latest communication bus structures and improve
on the original specifications, while maintaining backward compatibility with product
that was first released 19 years ago. The current revision of specifications (VXI
3.0) has increased the backplane speed to 160 MB/s.
Additionally, through the introduction of various interfaces to a VXI mainframe,
users
can communicate to the instruments via various open-communication links including
GPIB, Firewire, USB and most recently, Gigabit Ethernet. This versatility and adherence
to backward compatibility has allowed system designers to utilize the latest advances
in technology, while maintaining existing investment. Bridge interfaces have also
been introduced on the VXI platform that allow system designers to seamlessly integrate
other platforms like LXI with VXI in hybrid systems. A VXI-LXI bridge interface
(slot 0) provides a mechanism through which a VXI mainframe and instruments become
part of an LXI network. It is for these reasons that system implementations continue
to make use of the VXI architecture in the original target market of military and
aerospace, as well as the automotive, telecommunications and semiconductor industries.
The physical layout of VXI modules makes it the preferred solution for higher
performance applications in both test and data acquisition application spaces. For
example, the center spacing and card depth allow for the use of more rugged and
ergonomically-friendly connectors in single-slot modules and also for more robust
components. This is particularly evident in signal switching, the heart of virtually
every ATE, where recent advancements in technology allow for very high channel counts
of high-voltage and high-current relays with densities that are unmatched in any
other platform. Physical layout also plays a critical role in data acquisition applications
where signal conditioning for sensors such as strain gages, thermocouples and accelerometers
can be integrated into the module without sacrificing density or performance.
One of the most important aspects of the success of the VXI platform and why it
continues to thrive is that significant investment is being made by consortium members
in the form of major product introductions. Suppliers continue to introduce new
cutting edge products to address today’s test and measurement challenges. Examples
of these are new synthetic dynamic signal analyzers that are considered the ‘gold-standard’
for modal and rotational applications. A commitment to sustaining engineering and
designing out component obsolescence that inevitably occurs in a platform that has
a 19-year track record has ensured that test programs continue to execute without
significant engineering investment by the user.
The VXIbus has a 19-year track record of supplying high-performance and high-density
instrumentation to the test and measurement and data acquisition markets. Its versatility,
ability to adapt and integrate the latest technologies, and adherence to backward
compatibility has provided a combination of stability and forward looking technology
to the customer base for which the platform was originally designed. New product
introductions by a number of suppliers, and new system installations that heavily
rely on the VXIbus architecture ensure that the platform will thrive well into the
future making it the ‘time-tested bus you can trust’.