Combining the attributes of rack-and-stack instruments and modular test capabilities rolled into compact and flexible packages, Agilent Technologies (Palo Alto, Calif.) and VXI Technology (Irvine, Calif.) are debuting a new standard called LXI (LAN extensions for instrumentation). It's billed as a next-generation, LAN-based modular platform standard for automated test systems.
VXI Technology is already supplying the industry with high-density modular instruments and switching systems for both electrical and mechanical test. All of its products are based on open-platform, computer-independent standards.
Best Of Both
It's a natural then for the Agilent-VXI Technology nexus to endow LXI with built-in measurement science and PC-standard I/O connectivity from rack-and-stack instruments, and the modularity and size reduction of cardcage-based systems. LXI also combines compact packaging with high-speed I/O.
As a standard, LXI will be managed by the LXI Consortium, a not-for-profit corporation made up of test-and-measurement companies. The group's goals are to develop, support and promote the LXI standard.
For starters, LXI uses standard I/O. It's based on the popular IEEE-802.3 specs for networking. LXI is also uses standard TCP/IP (Internet Protocol) sockets, VXI-11 instrument discovery, and IVI-COM drivers.
LXI also relies on standard 1U and 2U-sized racks, and depths can be 13.6-in., 16.6-in., or 25-in. There's also
No cardcage or Slot 0 required.
It's Well Defined
"While the VXI bus is an ideal standard for all high-density, high-speed applications, LXI combines the benefits of VXI and Ethernet and provides users with a well-defined platform for high-performance instruments for applications not typically addressed with VXI," notes Paul Dhillon, VP of VXI Technology.
Agilent helped create VXI in 1985 to reduce the size of instrumentation for the military and improve performance for those high channel-count applications. Now, Dhillon says that Agilent and VXI Technology jointly leveraged their history of modular instrument design to introduce the LXI platform. The companies claim that LXI is a logical and practical step in the progress of open-standard instrumentation for test systems.
With Ethernet integrated into nearly every computer, it's also the most widely accepted communications interface. Users seem to like the approach. Some say they like the idea that you can plug instruments into a LAN and they will all talk to each other. Others point out that modular instruments are good but they don't want to deal with expensive cardcages and interface cards.
Long Life-Cycle Instrumentation
At the same time, networking hardware is becoming less expensive, speed continues to increase, and LAN offers peer-to-peer communications not available in other point-to-point interface standards.
As such, test-and-measurement engineers are increasingly realizing the benefits of high-speed LAN as an alternative to test interfaces such as the venerable IEEE-488/GPIB (General Purpose Interface Bus), which is now challenged by the industry's need for lower cost, higher bandwidths, and faster data transfer rates.
"LXI's LAN-based architecture provides the basis for long life-cycle instrumentation implementations," avows Pat Byrne, VP and general manager of Agilent's Wireless Business Unit. "LXI isn't limited by bandwidth, software, or computer backplane architectures." Byrne adds that LXI leverages ever-increasing Ethernet throughput, making it the best approach if you're facing next-generation automated test system challenges.
Beyond that, the synchronization and control of multiple instruments remains a prerequisite for most functional test applications. These are dependent on event detection, and stimulus/response handshaking or phase relationships.
Using LXI, you will be able to choose the best synchronization approach. For example, you could include an auxiliary trigger subsystem (such as TriggerBus), or the IEEE-1588 precision clock sync protocol, whichever best suits your application.
Design Validation Or Manufacturing
LXI test-and-measurement modules are optimized for use in design validation or manufacturing test systems. LAN connectivity enables modules to reside and be accessed from anywhere in the world.
Unlike a modular cardcage with an expensive power supply, backplane, controller, and MXI cards and cables, LXI modules are self-contained with their own processor, LAN connections, power supplies, and trigger inputs. LXI modules are either one-rack or two-rack units tall in full-width or half-width, making it simple to mix-and-match functions.
Instrument Pages By Web Browsing
Signal I/Os are also located on the front, with LAN and AC power located on the rear of each LXI module. What's more, LXI modules are controlled by a computer and therefore don't require displays, buttons, and dials of conventional rack-and-stack instruments. Instead, LXI modules use standard Web browsers for troubleshooting, with Web-based troubleshooting tools, and LXI uses the aforementioned IVI-COM drivers for communications.
Click here for additional information about the LXI Consortium product offerings, licensing, and specifications.
Click here for a backgrounder from Agilent.
More information about VXI Technology is available at its Web site, or by calling (949) 955-1894.