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.
4
Figure 2. In an automotive test system, LXI
components enable greater scalability and
flexibility to meet present and future needs.
