New-Tech Europe | April 2016 | Digital edition

Hardware Abstraction Layers (HALs) significantly mitigate the impact of hardware obsolescence, but are difficult to justify in the absence of a long-term support strategy.

A third and often hidden hurdle is the answer to the question: is better really better?The specifications of this new oscilloscope are multiple generations of technology ahead of the obsolete equipment, so where’s the issue? The issue comes when, for example, you insert this new oscilloscope into the system and the rise time or settling time measurements change significantly because you’re sampling at three, five, or 10times the rate of the previous instrument, which results in dozens of incompatible TPSs that previously provided great system utilization. Another issue arises when legacy TPSs require trigger functionality that instrument vendors made obsolete years or decades prior. In this situation, the test engineer is challenged with looking across the entire database to identify which TPSs will be broken by inserting a new instrument that does not support the legacy trigger functionality - a database which often doesn’t exist and requires weeks or months of manual effort to identify. In order to minimize the unknown risks of TPS rehosting, many test engineers are taking advantage of software-designed instruments (SDIs) to give more flexibility in the rehosting process. Software-designed (also known as synthetic) instruments combine core analog and digital front-end technology with powerful, user-programmable FGPAs to provide the most flexible instruments on the

While difficult to accomplish, emulating legacy

instrument capabilities

greatly reduces the risk of TPS migration issues.

Software- Designed,

or Synthetic Instruments, offer a unique approach to test equipment emulation

significantly reduced by abstracting vendor-specific hardware and drivers into a HAL or measurement abstraction layer (MAL). The test engineer is also tasked with evaluating the driver stack of the new instruments to ensure they plug into the HAL to mitigate the risk when migrating the thousands of TPSs still to come. Many HALs utilize the IVI driver class where possible and supplement with Plug-and-Play drivers. Since this example is an oscilloscope, we’ll make a blanket claim that the test engineer has it “easy” and gets a pass on software because there is an existing IVI class specified for oscilloscopes. Hardware Abstraction Layers (HALs) significantly mitigate the impact of hardware obsolescence, but are difficult to justify in the absence of a long-term support strategy.

will introduce a massive amount of documentation changes (not to mention any possible signal integrity issues with changing cable lengths to the mass interconnect). This form-factor challenge is one of the many reasons that modular platforms like PXI (and formerly VXI) have dominated the Aerospace/Defense ATE market for the last 30 years. By following the strict guidelines of the PXI specification, a scope from vendor A will be the same size and utilize the same backplane power as vendor B, giving test engineers an easier upgrade path for their systems. The second hurdle in the road is hardware abstraction layer (HAL) integration. Any test system that is expected to last for five to 10+years will inevitably have planned maintenance and operational costs. These are

New-Tech Magazine Europe l 21