How do people / companies deal with compliance testing (CE, UL, FCC, etc.) what I would call "platform-oriented and modular" products?
The idea being that a family of products might exist, where a lot of the electronics and firmware are shared among them, but each variant has different modular sub-systems integrated, and corresponding differences in firmware. Let's assume the product is an intentional radiator, using an FCC registered Wi-Fi module to keep things concrete, and that the product is powered by a UL marked 5V AC/DC USB wall-wart.
What strategy do you use to certify for compliance all modular combinations of the product family of products. It feels like modularity is a good design goal, but if it implies hundreds of variations each having to be independently tested for compliance, it seems untenable financially for real products. Is there a nuance I'm missing that makes the economics of modular design work from a compliance standpoint?
In 2018 it's also not uncommon to have field upgradeable firmware. This gives rise to the question of what exactly is tested for compliance? Does updating firmware in the field invalidate compliance marks?
Do the institutions that govern product safety and electrical compliance have allowances for these types of concerns, or are they just becoming dated? I want there to be a method to say: I tested the product in these configurations, and they represent a superset of all possible configurations, and they all met the regulatory standards; therefore other hardware configurations and firmware updates in the same family are compliant, no more testing required. Is that possible? Do product test labs support that sort of thing?
Best Answer
You're definitely on the right track with:
Having worked at UL for a few years, I can speak to it from the safety side, although I don't have experience on the EMC end. This wasn't an uncommon way of testing these types of modular designs. What you'll want to make clear is how these systems can be put together; i.e. "The end product will use one of these 5 power supplies, one of these 4 I/O modules, 2 of these XYZ widgets, and up to 4 of these ABC widgets."
Then, what you try to do is put together a "worst-case" end-product; the one that deals with the highest voltage, current, and overall power. Maybe this is one combination, maybe its a couple.
Then, the testing is representative of the entire set. Again, this was very common. My advice to you would be to propose your own test plan, explaining why the ones you chose are worst-case. Make it so the testing engineer only has to say yes, rather than try to choose on their own.
Hope this helps on the safety (fire and shock) side.