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EMC Pre-Compliance Visit: What to Expect and Bring?

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techy101:
First some background: I’m a young engineer (young in the field, not age) having returned to school then graduated at the end of 2016. I work at a small medical device company, am the only engineer here, and have spent the last year developing a new product. It’s a 4-cell NiMH powered iontophoretic stimulator that contains four 5VDC->120VDC flyback converters in an ABS enclosure. It has external cables that would be connected to a patient and is the first truly new product we’ve made in about eight years.

I am taking this device to a testing lab tomorrow for IEC 60601-1-2 EMC pre-compliance testing, have never done this before, and was hoping to get some guidance as to what to expect and what to bring. We don’t have any in-house EMC test equipment (probes, spectrum analyzer, etc…) so I feel like I’m going in pretty blind. I’ve been told that most devices fail the first time and I’m prepared for that, especially since this is my first time designing for EMC and have what I imagine to be a noisy device. I have five prototype units that I’m bringing along and have sprayed the inside of one unit with MG 843AR EMI/RFI shielding to compare the difference between coated and non-coated enclosures. We weren’t able to get a factory-coated enclosure in time for testing.

The engineer I talked to at the facility recommended that I do radiated and conducted emissions, ESD, and conducted immunity for sure. He said the radiated immunity takes a very long time, but I might be able to get in one pass. He also inquired if I was okay possibly destroying one of my devices (which I am); which tests might be expected to destroy the device?

Do people have any suggestions on how to best make use of my time there and/or what tools I should bring? I realize that’s a pretty vague question, but nerves are getting the better of me right now and any guidance would be appreciated.

Thanks!

Ice-Tea:
ESD may damage your device.

As for what to bring? Copper tape? Common mode clamps? If you want to do some on-site debugging maybe inductor kits, capacitor kits, solder gear,...

mikeselectricstuff:
Do ESD last, as that might kill something.

Take as many spare boards, options for filters, shielding etc. as you can, a good soldering iron & any other rework gear you may need. Assume nothing about what tools may be available there.




pix3l:
If the device has external (USB) cables it's always useful to have some ferrite cable clamps on hand (EMC lab will likely also have some available but then you have to go with the ones they have there or retest once you've chosen a ferrite clamp).

SiliconWizard:
Bring anything needed to make your device function in a nominal way and what's needed to show it does (that may include test tools, test programs, etc)
Bring the schematics and be prepared to describe what your criteria of "functioning properly" in different use cases are, as this is how tests will be issued and judged. If your device can be used with cables and accessories, bring them.

Usually, testing labs already have a lot of equipment including soldering stations and many lab instruments, so this is rarely needed to bring them (and if they do IEC 60601-1-2 compliance testing, which is for active medical devices, this is likely to be a decent lab), but ask just in case before going there so you don't get stuck. They usually also have lots of component kits including inductors, ferrites, resistors, capacitors, ... just bring anything extra that could be needed, such as smd fuses if your device has any, etc. But again, ask them.

As already mentioned, bring several indentical units, as some tests may be destructive. Most likely ones are ESD tests, but some immunity tests could potentially be destructive as well if some part of your design is particularly sensitive to that. Also, if your device contains some MCU or the like, destruction could also occur as a consequence of some immunity tests getting the MCU in an abnormal state that would cause it to control the underlying hardware in an unexpected way (causing shorts or other issues...)

A very important point as I mentioned first is to be able to make your device function without any direct user interaction, as you will usually not be able to enter the testing chambers while the test is running (for most emission and immunity testing). (This isn't the case for ESD testing which is usually done manually in the lab.) So, for instance, if your device required the user to press a button continuously to execute some function and then stopped once they release it, that would be a problem. You'd normally have to find a way to make the device execute that function continuously for testing.

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