ESD Testing IEC 60601

[Ohad Barsheshet]

Hey Guys, Recently it came to my attention from one of my consultations that my screens for my medical device will go through ESD Testing (Electro-Static Discharge)

The Screen i'm Using for GUI will be a generic 7 inch screen where raspberry pi 4 b will be mounted to its backside.

I've been advised to use TVS Diodes and a proper ground path to be protected from that damage both for testing or normal operation essentially harming my Essential Performance of my medical device.

It would mean i have to take my raspberry pi and change the circuit in order to implement those components or groundings.

I've never tried anything like that before, could anyone pour some wisdom on the subject?

Thanks In Advance,
Ohad.

 

[FelipeSchneider]

Hey Ohad, maybe ESD will be the least of your problems...

First, you need to describe where you are planning to market your device, if you want to go to the USA, then you need to observe the IEC TR 60601-4-2, which demands some "extra" performance from your device (i.e. your device may not reset during an ESD test). Otherwise, Europe and Brazil accept that your device resets or even stop working if this does not affect your essential performance.

However, you must be very careful with your emissions (conducted and radiated) because if you pass certain limits your device will not be able to be marketed and using a commercial rasp + a not prepared display may give you very bad emission results.
Another critical point is your power supply, it needs to meet many critical requirements.

Good luck!

 

[Ohad Barsheshet]

Hey!

This is a prototype for first testing in my country (Israel) I have a consultant That said As long as the display is protected from ESD and you mention in his Essential Performance that in case of ESD situation the device will reset in X time that it is acceptable.

In the future I'm certain we will use medically approved screens. (ATM they are too expansive to play with)

our end goal is to market in the USA, Thanks for the helpful information I was sure mentioning the device may restart will be sufficient.

You mentioned my power supply, Its is NEVO +1200M (Medical Grade Power Supply) so its not my any concern for me.

My Consultant said we should plan a good Grounding Route for that ESD test in our Raspberry Pi Circuit and implement ESD Protective components, but he wasn't very clear on the "How" to do it.

If you have any practical advice I would be grateful.

Best,
Ohad.

 

[FelipeSchneider]

The EMC field is not something simple and simple explanations are doomed to be incomplete and it is very hard to give you good advice without knowing your device.

I would avoid as much as possible using a not professional Raspberry Pi, not only because of EMC/EMI but because you have no control over the components which could create problems in your quality system in the future (I might have a strict view on this one). I've seen EMC problems caused by a simple Arduino.

A good starting point for this is the book by Henry Ott: Electromagnetic Compatibility Engineering.

 

[Ohad Barsheshet]

I appreciate your advice Felipe, Thanks for the kind help!!

 

[FelipeSchneider]

I forgot to mention: go for the part II of the book, EMC applications. You may find ideas there that may save you during the tests.

Another important thing to do is to book a development test day in a professional lab, then you will be able to test different settings and configurations, check which cables need some ferrites... All things that you will not be able to do or will have a hard time doing during the official tests.

 

[Ohad Barsheshet]

Yes!

I have been advised to book a development day, the same lab for the official tests offer that function! which is amazing for that matter since they will be the one to test my device, I will book a testing day soon in order to see where my flaws are

 

[optomist1]

Echoing Felipe's great posts, EMI/EMC, now just EMC?, is a deep, deep subject, and at times can appear to border on sorcery, so proceed with due caution, and attention to detail.