Two manufacturers of test-and-measurement equipment—Agilent Technologies (Palo Alto, CA) and VXI Technology (Irvine, CA)—recently joined efforts to introduce the LAN-based eXtensions for Instrumentation, or LXI. This open standard, maintained by the LXI Consortium (San Diego, CA), will simplify instrumentation communications by adopting standard Ethernet (IEEE 802.3) LAN hardware and software. Twelve other companies joined the LXI group in December.
A typical LXI module provides its own processor, LAN connection, trigger inputs, and power. Developers can start an LXI-based system with one module and add others as needed. And as a system grows, engineers need not calculate new cooling and power requirements, buy a larger backplane or enclosure, nor switch to a new system architecture. LXI-based modules add another benefit: They readily work with other LAN-based or IEEE 488-based instruments.
Why develop another standard when VXI, PXI, USB, and others already exist? According to the LXI Consortium, for one reason or another, those buses have not gained broad acceptance within the T&M industry. Also, the widespread use of LANs will work in favor of LXI-based systems: Even inexpensive desktop PCs include Ethernet ports, so engineers can quickly get LXI modules and test systems up and running.
LXI modules use standard Interchangeable Virtual Instrument (IVI) drivers to communicate with each other and host computers. These drivers simplify test-system development and programming and make it easy to substitute one instrument for another without requiring code revisions. (PXI and VXI systems use these drivers, too.)
The Ethernet community has already addressed engineering issues that surround high-speed communications, and IC and module manufacturers offer a wide variety of products that simplify adding Ethernet ports and circuitry to existing designs. In addition, software suppliers produce ready-to-go TCP/IP stacks that simplify the software interface between existing applications and firmware code. This existing level of support makes the adoption of Ethernet—and LXI—a logical choice for instrument manufacturers and users in the years ahead.
An Ethernet LAN will connect LXI-based instruments as
well as others that offer an Ethernet port. Communication bridges
link-networked equipment to older