VTI and Agilent Technologies co-founded the LXI Standard in response to customer
requests for a common, simplified instrumentation platform ideally suited for small
to medium channel density and distributed test applications
• Ethernet is an established high-speed bus that continues to evolve
• Increases in data throughput not matched by GPIB and MXI
• Stable architecture that provides backward compatibility
• Computer platform and OS independence
• Low-cost interface, cabling and accessories
• Unlimited range and nodes
The LXI consortium was co-founded by VTI Instruments (VTI) and Agilent Technologies
in 2004 to offer the industry an open-architecture instrumentation bus that would
leverage all of the benefits of Ethernet for test and measurement. The intent was
to provide ‘one’ forward looking architecture for small-to-medium density and distributed
applications. By leveraging the two most successful instrumentation platforms (VXI
and GPIB), LXI has been adopted and carried forward by approximately 50 of the leading
manufacturers of test and measurement instrumentation.
LXI’s compact, flexible packaging, high-speed I/O, and reliable operation meet the
needs of R&D and manufacturing engineers delivering electronics for the aerospace/defense,
automotive, industrial, medical, and consumer electronics markets.
The VXIbus is an ideal platform for our customers that require high-channel density
in their applications. LXI now allows us to develop leading edge products with the
same longevity advantages that VXI has given the industry, for the applications
that VXI was not designed to address.
VTI has been instrumental in the development of the LXI specification, contributing
significant engineering resources to the technical working groups tasked with content
generation, test, and validation.
The LXI Specification extends the capabilities of typical Ethernet by addressing
key functional areas that are necessary to ensure instrument interoperability, performance,
and usability. The primary sections include the following:
• Physical
• LAN Device Synchronization and LAN-based Triggering
• Module-to-Module Data Communications
• Hardware TriggerBus
• Programmatic Interface
• LAN Configuration
• WEB Interface
The base level of LXI compliance features device discovery, web browser control,
and a common application programming interface (API). Web browser functionality
provides out-of-the-box operation without the installation of any software or drivers,
while device discovery identifies all LXI compliant devices on the network, simplifying
startup and configuration.
IEEE 1588 further extends LXI instrument functionality by adding LAN-based synchronization.
IEEE-1588 defines a precision clock synchronization protocol for networked measurement
instrumentation exclusively over the LAN connection.
Instruments can be synchronized, and activities initiated, using LAN commands with
accuracies in the sub-microsecond range. This approach is ideal for distributed
measurement applications.
The addition of the TriggerBus Hardware Trigger Interface provides the highest level
of synchronization and platform interoperability. This interface is ideal when applications
require hardware-level triggering for deterministic command, response and handshaking;
system-level clock and trigger distribution is also possible. The TriggerBus interface
also provides a convenient mechanism for interfacing to other open-standard platform
architectures, such as the VXIbus, thus leveraging current test hardware investments.
LXI test and measurement modules are optimized for use in design validation and
manufacturing test systems with LAN connectivity enabling modules to be accessed
from anywhere in the world. Unlike a modular cardcage, LXI modules are self-contained
with their own processor, LAN connections, power supply and trigger inputs. Signal
I/O connections are typically located on the front panel, with LAN and power connections
located on the rear. LXI modules eliminate the need for displays, buttons and dials
traditionally found on rack-and-stack instrumentation. They use standard web browsers
for troubleshooting and implement IVI-COM drivers for communications, thus simplifying
system integration.
