Series 18 – Episode 2 – PXI, LXI, & the modular test puzzle: finding the right fit

In the world of electronic test and measurement, two prominent standards have emerged: PXI and LXI.

Sarfi offers insights into these critical technologies that are reshaping automated test systems.

Both standards share fundamental similarities: they're built on ubiquitous consumer technologies (PCI and Ethernet) and aim to provide vendor interoperability. However, their approaches differ significantly.

PXI is a card-based modular standard with strict requirements for chassis construction, power, and cooling. Its modular architecture allows for scalable, flexible test system designs. Modules from different vendors can typically interchange within the same chassis, providing unprecedented system adaptability.

LXI, by contrast, is primarily a network-centric standard focused on consistent instrument communication over Ethernet. It doesn't mandate a specific mechanical design, giving manufacturers more flexibility in implementation.

The choice between PXI and LXI depends on specific application needs. Some scenarios favour LXI, particularly in distributed measurement environments like aerospace and military testing. LXI allows instruments to be strategically placed near measurement points, reducing cable complexity and maintaining signal integrity. Cost considerations are crucial. A PXI chassis can incur significant overhead, with potential premiums of up to $1,000 per slot for high-speed backplanes. LXI offers more economical alternatives, especially for less bandwidth-intensive applications.

Interestingly, hybrid systems combining both standards are increasingly common. No single platform suits every test requirement, and engineers often leverage the strengths of both PXI and LXI.

Looking forward, modular architectures will continue evolving. PXI, built on adaptable technologies like PCIe, appears well-positioned to incorporate emerging innovations. The key is maintaining an open, interoperable approach that allows engineers to select the most appropriate solutions for their specific challenges.

As test systems become more complex, the ability to mix and match technologies will remain critical. Whether through PXI's precise modular design or LXI's flexible networking capabilities, the goal remains the same: creating efficient, adaptable test infrastructures that can meet the demanding requirements of modern electronics development.

To hear more from Tom Sarfi, you can listen to Electronic Specifier’s interview on Spotify or Apple podcasts.