The LXI System You Didn't Know You Were Using

It’s a rather quiet secret that the LAN eXtensions for Instrumentation (LXI) standard has been growing by leaps and bounds. The first revision of the standard is barely four years old and yet more than 1,300 products have been certified compliant. This is undoubtedly the fastest ramp up of any test and measurement standard in history.

Both the strength and stealth of LXI come from the fact that it uses industry-standard Ethernet technology. It fits seamlessly into existing networks so test equipment can be attached to a computer with only a few LAN cables and an inexpensive switch or router.

Test-equipment manufacturers have enthusiastically adopted LXI. But what about users? This question is more difficult to answer than you might imagine. Many LXI instruments contain multiple interfaces such as USB or GPIB in addition to the LAN interface. As a result, simply counting the number of LXI-compliant instruments shipped doesn’t reveal how many instruments are being used.

There’s another catch: Unless you notice the LXI logo on the front, it isn’t always easy to distinguish an LXI instrument from an instrument with a plain LAN interface. A recent survey asked customers about their usage of instrument communications standards. The results showed 69% connect to instruments using Ethernet, with just 8% saying they connect via LXI. It seems likely that the real number is somewhere in between.

Here at Agilent, we’ve noticed many customers use instrument LAN ports without realizing it’s an LXI instrument. On the other hand, it seems that most end users have a LAN connection on their test system, but the actual number of cases in which the LAN controls the instruments is lower than reported in the survey.

Some users think they aren’t using an LXI instrument unless they’re utilizing the advanced time capabilities or cabled triggers. The good news about LXI is that it works just like GPIB: Simply connect the cable and start programming. Many LXI instruments even have compatibility modes that enable GPIB-style programming.

As end users continue to realize the benefits of connecting an instrument without any special cabling or controllers and using each instrument’s built-in Web page, the recognized adoption rate of LXI is sure to grow. Now that a critical mass of LXI products is available, there’s no need for long evaluations just to prove that it’s possible to build an LXI-based test system.

What comes next? Clearly LAN connections are well accepted in the test community. With LXI as the default for LAN-connected instruments, LXI appears to have a very bright future.