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www.us-tech.com
July, 2014
PXI Expansion Enhances Automotive Dashboard Testing
By Alan Albee, Teradyne, MA
boards was experienced recently by a manufacturer of high-volume auto- motive dashboard electronic units when they replaced a functional test system with a standard in-circuit tester (ICT) with PXI modules. The benefits of the change included 60 percent lower acquisition costs, high- er test coverage, faster test through- put, reduced equipment floor space, and lower operational costs. This particular manufacturer
T
needed to update the company’s test strategy to keep pace with increasing demands for its automotive dash- board systems. The existing test strategy consisted of a comprehen- sive functional test running on a
The DUT was a dashboard controller, a medium-com- plexity circuit board with 500 components, including 100 light-emitting diodes (LEDs).
commercial test system. The test sys- tem, which had been discontinued by its manufacturer, was becoming increasingly difficult to support. The goal was to find an alternative test solution with equivalent or better test coverage, faster test throughput,
PXI TestStation expansion board.
cuit board with 500 components, including 100 light-emitting diodes (LEDs), passive analog components, stepper motors, push buttons, an audio speaker, phototransistors, electrically erasable programmable read-only memories (EEPROMs), multiplexer (mux), and liquid-crys- tal-display (LCD) drivers. The basic test requirements for the automotive dash board specify that a solution can ensure that all components have been properly placed and that the
bus after power up, upload of dedi- cated firmware to the FLASH memo- ry to perform self-test procedures, storage of calibration data in EEP- ROM, simulation of loads, measure- ment of very precise time intervals, verification of audio levels, and measurement of LED colors and intensity. The dashboard controller’s man -
ufacturer examined three options for satisfying its test requirements:
he flexibility and affordability of modifying test stations equipped with PXI expansion
and lower operational costs. The manufacturer’s electronic
system to be tested, a dashboard con- troller, is a medium-complexity cir-
board is free of short- and open-cir- cuit defects. Functional test require- ments include communication with the controller-area-network (CAN)
l Replicate the current functional
test strategy as best as possible by integrating off-the-shelf PXI instru- ments in a custom functional rack system.
l
Deploy a two-stage test strategy, where the first stage performs tradi- tional ICT testing and the second stage performs defined functional testing.
l Replace the existing functional
test system with an ICT system that could be extended to support func- tional test requirements in a single test stage.
The first option offered the bene-
fit of most closely matching the man- ufacturer’s current test strategy and allowing for direct transfer of existing tests in the fastest time possible. However, this option also came with the same weaknesses as the existing test solution, including high support costs, indeterminate fault coverage, limited diagnostic accuracy, and slow throughput. By adding traditional ICT to the mix, the second option would improve fault coverage and diagnostic accuracy, as well as simpli- fy functional test requirements. However, it would also increase both acquisition and operating costs because it would require two test sys- tems, two test fixtures, and additional product handling. The third option was perceived as ideal since it would
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