Testability Does Not Arise at the Test Stand – But in Design
An assembly can function technically and still be a series problem.
This is the case when the relevant functions cannot be tested clearly, quickly, and reproducibly.
In development, many measurements can be done manually: connecting the probe, opening the debug interface, observing firmware status, varying load, tracking signals. In production, this logic no longer works. Defined access, short testing times, clear limits, and unambiguous fault localization are what count.
The bottleneck is rarely in the test stand.
It lies in the design.
Missing test pads, unfavorable reference grounds, unreachable sense signals, uncontrollable operating states, or missing diagnostic modes make the testing process unnecessarily complicated. For highly integrated assemblies, AOI alone is not sufficient. And a functional test that only evaluates "pass/fail" often provides too little information for stable series quality.
Design for Testability therefore begins much earlier:
Which nets need to be accessible?
Which functions can be controlled in isolation?
What firmware test modes are required?
How are programming, calibration, and EOL testing secured?
How can a fault be clearly traced back to a component, solder joint, firmware, or process?
At Control Motion Electronics, test concepts, testing tools, ICT/EOL strategies, and manufacturing-friendly layouts are already considered in development. This is particularly relevant for power electronics, motor control assemblies, and embedded systems, where electrical function, software state, and operating conditions are closely coupled.
Testability is not a subsequent testing step. It is a property of the design.
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