Test Connections - December 2020

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Form, Fit, Function (FFF) Solutions Simplify Product Obsolescence Challenges


Addressing Obsolete Instrumentation Challenges
Test system service life extension initiatives to address obsolete instrumentation continue to place pressure on engineers to find alternatives that deliver equivalent functionality and performance, without the uncertainty and expense associated with test program set (TPS) requalification.
  
There are several strategies for addressing the replacement and maintenance of obsolete instrumentation including the stockpiling of spares, ongoing maintenance and repair (when possible), secondary market instruments (typically used/refurbished), TPS migration to similar COTS instrumentation, and finally implementing a FFF replacement.

          GP1552AH

Table 1 summarizes the replacement alternatives along with lifecycle, cost and risk assessments.

Replacement Strategies

Table 1. Replacement Summary

The stockpiling of spare instruments is one way to mitigate system downtime and maintenance issues.  The life span for commercial instrumentation is typically 5-7 years, and with new demands being placed on existing test systems life cycles of 20 -   30 years are not uncommon. Therefore, this is only a short-term solution at best and the additional upfront, stocking and maintenance costs may make this approach unattractive.

Ongoing maintenance and repair of obsolete instrumentation is another option but several drawbacks including increased cost and repair time, as well as qualified component availability, are common.  Even if some systems are reserved for cannibalization, the source of instruments and parts will eventually be exhausted.  Obtaining new or refurbished instrumentation on the secondary market is another option; however, these instruments are often sold as-is and may not deliver the required performance.  Both of these alternatives deliver short-term solutions to a long-term problem.

One long-term solution involves replacing the obsolete instrument with a similar, new commercial-off-the-shelf (COTS) instrument delivering comparable functionality and performance.  In most instances the replacement instrument’s software functionality will not be compatible, requiring a software driver wrapper, or adapter, to mimic the legacy instrument’s commands and response characteristics.  However, even with the use of a software wrapper that mimics the legacy instrument’s functions, this implementation will necessitate costly reverification and may require upgrades to all test programs (and system self-test), which can be an extensive effort.

Form, Fit, Function replacement instruments deliver the most technically superior, cost effective and sustainable long-term approach to test system obsolescence management.  MTS designs and delivers FFF replacement instrumentation (See Table 2) that is functionally, electrically and mechanically equivalent to the legacy instrument, including the software interface, preserving initial investments in the test system and the associated TPS development and validation activities.

FFF Replacements

Table 2. MTS FFF Legacy Replacement Reference

Preservation of existing TPSs, without requalification, is critical and great care is taken to replicate the legacy instrument’s functionality, allowing system self-test and test programs to execute without modification. This eliminates the time and costs associated with extensive reverification and also provides the flexibility to use either the legacy instrument or replacement instrument with existing test programs (See Figures 1 and 2).

GP1665W

Figure 1. GP1665W – Wavetek 178 Replacement

GP1552AH

Figure 2. GP1552AH – HP 8160A Replacement


For a more detailed look at instrumentation obsolescence management please reference Knowledge Base Article #Q200293 and the associated white paper “Addressing ATE Instrument Obsolescence with Form/Fit/Function Compatible Solutions - A Case Study".

To discuss your unique legacy instrumentation replacement requirements, contact us today!