EMC testing

Electronics testing using low voltage EMC testing standards

Vehicle manufacturers require embedded systems to withstand certain electric conditions defined within standards documentation.

Each OEM’s EMC testing standards have similar aims, but each sets out to build on previously written standards. As a result, each standard varies to a reasonable degree. It is possible however to group tests into relatively few categories aimed at similar use cases. Some examples are Engine cranking or starting issues, relay chatter issues, intermittent connection issues, over-voltage issues, and more.

Robustness testing of low voltage systems

You will usually have to meet standards to demonstrate that your component or system meets formal requirements before you begin production deliveries. This will normally require driving your system with repetitive electrical waveforms designed to display typical worst case voltage curves.

Techniques of robustness testing can be used to gain a better understanding at both a system and a component level of the system under test.

Parameterising automotive low voltage waveforms for test 

When trying to test automotive systems a common and very effective method is to parameterise these signals, essentially breaking complex waveforms down into a just sufficient number of voltage steps and ramps and corresponding time periods.

This technique essentially simplifies the process of testing while maintaining the key features of the waveforms likely to cause issues during test. This then allows you to focus on producing repeatable waveforms and applying them to the devices being tested.

PSU vs specialist hardware for low voltage testing

Power supplies that can both source and sink output current are very rare and tend to be only available in very high-end PSUs.

As a general rule PSUs only source current from the positive pin and do not actively drive the negative pin downwards, pulling current into the PSU.

Additionally, PSUs may offer one or the other option, i.e. either ‘sourcing’ or ‘sinking’, but not both on the same piece of hardware.