DUT TEST SOFTWARE DEVELOPMENT Testing for EMC target is to characterize your electronic module per specific standards adopted as reference by the manufacturer. There are two major areas of software development involved in EMC/EMI testing: automating the equipment and its data acquisition system activating the module’s functions via CAN bus. In such a test setup you can have 3 PCs running the software that handles the EMC test equipment and another two PCs to control the module’s exerciser and bus interface. Ideally is to reduce the number of factors that can trigger false errors and poor readings by developing software capable to handle simultaneously both the equipment and the CAN bus messages via GPIB/RS232. What is really important here is to develop for MCU based automotive electronic modules not only routines used by car dealers for diagnostic purpose, but also routines that test and report the I/O status for those functions that must be validated for RF and electrical stress immunity. This will eliminate the module’s exerciser (or load box), that usually contains its own electronics and software, from EMC/EMI test setup. One of the key elements for EMC correlation process is testing always the DUT’s functions in a repeatable scenario, especially for MCU based controllers. The perfect case will be to run real functions against real loads but this is not easy to achieve during the product development process. New revisions in DUT’s software require most of the time changes in DUT’s exerciser in order to adjust some PWM and/or timing for input switches. Running the module’s functions via CAN bus like in a real scenario is not always possible when this involves for example motors activated in a succession triggered by certain external conditions. Our strategy is to implement as part of DUT’s software functions dedicated for EMC testing, capable to repeatedly ensure a good reference for pass or fail in response to a bus message. Such an EMC function is preferable to be performed against passive loads, eliminating any false deviation caused by auxiliary electronics parts. The DUT’s software will determine based upon an I/O setup that covers the worst scenario in the car, whether the function was deviated from a normal execution and will raise in its response an error code indicating what sequence failed. This method offers a solid reference for both immunity and radiated EMC tests and can be easily implemented in different test sites.

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