Agilent Technologies LXI manual Cost, Scalability

3. Cost

Minimizing the overall cost of test requires fast, reliable testing at as low a price as pos- sible. Some trade publications have suggested that functional test adds no value: At this late stage, most manufacturers have inspected incoming parts, per- formed X-ray inspection and completed in-circuit test. While these steps do improve product quality, they do not eliminate the need for functional test because they cannot detect faults due to post-assembly product failures, design errors or inaccessible nodes.

Automakers’ seemingly con- flicting requirements compound matters. Instruments that deliver the necessary capabilities and performance at an attractive price can solve these issues, as can careful consideration of both initial hardware cost and recurring costs such as spares, warranties, local versus return- to-factory repair options and availability of rental equipment. In many cases, an instrument- by-instrument price comparison will show up to 40 percent reductions in the cost of LXI versus PXI hardware.3

It is also worthwhile to account for the learning-curve costs of cardcage instruments versus LXI. Cardcage instruments require the use of different software drivers for each devel- opment environment such as LabVIEW, Visual Basic and C++. LXI instruments generally offer a choice, enabling use of either drivers or SCPI.

4. Scalability

Figure 2 shows a typical auto- motive electronic functional test system built with LXI devices: expandable reed relay matrix, many armature-relay load switches, many channels of arbitrary waveform output and many channels of D/A conversion. In a cardcage-based system, these devices can quickly fill every slot, and the addition of just one more device requires another cardcage and computer interface. For systems requiring just a few cards, the cardcage adds cost and consumes space, though the empty slots allow for future expansion. LXI instruments provide the desired functionality, making it easy to upgrade functionality without adding a cardcage or computer interface. At most, the system may require the addition of a low-cost LAN switch to provide ports for added LXI devices.

Figure 2. In an automotive test system, LXI components enable greater scalability and flexibility to meet present and future needs.

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