Selecting an Approach to Build Flexible, Cost-Effective ECU Production Test Systems

Electronic control units (ECUs) were invented in the 1970s. At that time, people needed to improve fuel economy due to the oil crisis, which meant finding a way to make engines run cleaner and pollute less. Engines used a mechanical device called a distributor to control spark timing and a carburetor to control the fuel mixture. This mechanical system had minimal tuning and adjustment capabilities. The advent of the microprocessor in the 1970s provided an enabling technology capable of performing the complex high-speed calculations required for controlling spark timing and fuel mixture. In the early 1980s, ECUs became a standard component in most vehicles. As a computer designed to solve a very specific problem, the ECU is a fundamental component in an automobile.

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Design Challenges of Production Test Systems
As stated earlier, test is often considered a non-value-added process even though it improves the quality level of each phase of the manufacturing process. This belief drives test organizations to ensure that the test process is robust, thorough, fast, and cost-effective. To accomplish this, they must meet five main design challenges: reliability, throughput, flexibility, deployment, and cost.

1. Reliability
In production, test systems likely operate 24×7 with high volumes, and downtime is costly. The tolerance for partial, late, or missed shipments is close to nonexistent. Any delays in production, from false failures to unavailable test systems to calibration issues, can contribute to downtime and thus need to be under control. Test equipment must be reliable, and this reliability comes in different forms:

• Robustness of the hardware to operate in a production environment
• Quality and stability of the test software and test sequencing
• Overall maintainability of the system
• Available services from involved suppliers and third parties

When combined, these factors contribute to the challenges that test engineers face. They must seek solutions that give them enough time to develop the test system as best they can and be confident that it will continue testing reliably throughout the life cycle of the ECU.

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