Test of electronics for the automotive industry is full of challenges. The quality imposed by safety and reliability requirements, is close to that of the avionic industry. Quality certifications (AVSQ, VDA6, EAQF, QS9000, etc.) demand strict test and validation procedures to respond to faultless development, manufacturing, and delivery of the products.
Today's cars make large usage of a variety of electronic control modules (ECMs) also called electronic control units (ECUs). ECMs consist of a CPU and associated logic to convey input/output signals that control different components of the car. Some ECMs are responsible for delicate functions of the car, like the antilock brake system (ABS), while others control simpler functions such as power windows (i.e. the trunk door module, TDM). The ECM body computer implements most of the electronic functions on a modern car. Communication with the body computer is done via two specific busses with associated protocols— the controller area network (CAN) and the local interconnect network (LIN). The first is the most popular standard to date, but for some applications it might be too costly and is substituted by the less complex LIN solution. A LIN master node can connect the LIN network to higher-level CAN network, extending the benefits of networking all the way to the individual sensors and actuators.
OTHER CHALLENGESAdditional challenges are introduced through the different scenarios on which test should be performed. Initially the test platform is used in engineering, where quick changes and high interaction are required. Once in manufacturing, we can identify at least two different scenarios: the End-Of-Line stage and the Run-In stage. In the first one, final functional test of the body computer working with special firmware (instead of real loads) is executed to optimize speed and measurement accuracy. The Run-In stage executes the final functional test of the body computer with real firmware and real car loads (often involving high currents up to 35A and more). The Run-In test is often imposed by the extremely high quality requirements demanded by the car manufacturers for some modules.
RECONFIGURABLE TEST PLATFORMWhile intended to respond to a variety of applications, conventional automatic test equipment (ATE) is rarely suitable to combine the variety of requirements of ECM test at acceptable cost levels. On the other hand, dedicated lower cost solutions, built around PCI or PXI standard instruments, fail to adequately respond to the totality of requirements and do not offer the advantages of a welldocumented and supported common platform. Closely working with major automotive manufacturers, Seica has developed a flexible, scalable and reconfigurable test platform, the STRATEGY of VL, capable of addressing all the requirements of comprehensive, high quality and high throughput test with careful cost control. Easily reconfigured, the platform becomes a point solution at each stage of test, while maintaining the commonality of software, hardware and operating functionalities.
A pc, running under Windows/XP, controls the test platform. Digital communication with the unit under test (UUT) is assured via two CAN channels (programmable as low speed or high speed), one LIN channel, PCI Bus and a K Bus.
The core of the system is architected around a 40-slot test backplane with embedded 8 lines analog bus routing. All instruments and channel cards that configure the test backplane are controlled via a proprietary optical link connection, which allows zeronoise test environment.
Most stimulus/measurements functionalities are assured by a DSP-controlled multi-instrument subsystem, the ACL. This instrument-card includes 3 independent arbitrary waveform generators (AWG), multi-meter, timer-counter, and features signal analysis capabilities and digital scope functionalities. ACL is used both for structural, power-off and active in-circuit test and for functional test applications. Signal routing to the DUT is performed via configurable switching cards (64x2, 32x4 or 16x8) capable of serving up to 544 channels. Additionally, special high current modules have been designed to offer 20A-switching current on multiples of 32x2 channels. To avoid costly fixture add-ons, the test backplane is configurable with an optional dedicated module including 40 general purpose automotive outputs, loads, voltage references and optocouplers, another module with 20 automotive relays and service LEDs, another module with resistive loads and emulation for lights and other loads. The system can also easily integrate external instrumentation (GPIB, VXI, PXI or PCI), like Agilent programmable electronic loads or RF generator (1.16GHz) for remote control test.
STRATEGY VL FIXTURE ENGAGING MECHANISMTest program generation, debug and run time software are usually controlled on all Seica Test Systems by the VIVA environment. VIVA offers a highly efficient development environment, with connection to most CAE/CAD tools, powerful test generation algorithms, graphical edit and display tools, highly interactive debug and runtime environment, accurate diagnostics and paperless repair station. Given the need to extend utilization of the test platform up into engineering and development, where National Instruments tools are very popular, STRATEGY VL can also be equipped with a comprehensive LabVIEW and TestStand environment that allows full control of the system's operations under a potentially more familiar software.
THE TEST PLATFORM IN ACTIONReconfigurable to specific needs, STRATEGY VL platform will typically adopt a one-bay configuration, with edge connector access, for engineering/development positioning. In manufacturing, the EOL stage can be configured with twin fixture and pneumatic and motorized tools to assure highest throughput and lowest cost of operation. The Run-In configuration is arranged instead to provide direct access to DUT connectors.
During Run-In test all loads are active simultaneously as in real conditions, with the result of sometimes finding previously undetected faults. Point solutions for remote control test radio frequency (TRF) carry minimal, cost controlled configurations, but add the RF generator and a spectrum analyzer.
The solution provides dedicated stations working in parallel, all part of the same family and all easily transformed (EOL to Run-In or TRF and vice-versa). And as automotive requirements evolve, STRATEGY VL will maintain its value thanks to its expandable, open system, standards-base architecture.STRATEGY VL is part of the VIVA integrated platform (VIP) family of systems, which include PILOT and AERIAL Fixture- Less Board Testers, STRATEGY In-circuit and Functional Testers, VALID High Performance Functional Testers. All sharing the same core hardware and software architecture, the VIP products are ergonomically and electronically shaped and configured to best match automotive, consumer, defense, industrial, and telecom applications, from engineering to manufacturing, to maintenance test, and repair scenarios.
