EMC Immunity Testing EUT Monitoring Software

One of the hardest parts of EMC immunity testing is monitoring EUT (Equipment Under Test) performance. Not that it is hard-as-in-complicated but it is hard-as-in-difficult.

Concentrating on a display of figures scrolling past looking for small deviations in one or two characters sounds easy, but try doing it for a couple of hours straight whilst doing Radiated RF Immunity testing and you will be fighting an itch to defocus, stare off into the distance or check the news on your phone.

Go on, ask me how I know  😉

Not ideal when you only have a short (think a few seconds) window to catch potential problems or if you have multiple screens to monitor.

 

Introducing the Monitor-o-Matic 8000

To remedy this and improve the quality of our testing we’ve written a simple application in LabView to handle logging and display of data captured from the EUT during testing.

 

 

Specifications

  • COM Serial input to monitoring PC from EUT. all standard serial port baud rates and configurations supported
  • Use USB to RS-232 or RS-485 adaptors to connect serial port to EUT
  • Extract values / parameters from data stream
  • Plot numeric values on graph
  • Record min and max values seen during test to determine if EUT meets appropriate performance categories
  • Logging of all data during test (all data will be made available as part of any immunity testing carried out at U3C for post testing analysis)
  • Alerts/alarms for data that exceeds defined performance limits. These can be set to latch on in case of problems to prevent missed alarms

 

Use Requirements

1) EUT has the ability to output serial debug ASCII text data for all key parameters like

  • analogue sensors (e.g. temperature, pressure, humidity, light, voltage, current, etc)
  • digital I/O values (e.g. High/Low, True/False)or system status
  • raw digital values read from other parts of EUT
  • checksums from memory
  • whatever other parameters that you need to monitor to ensure the EUT is working as intended during the tests

2) Format could be human readable text, comma delimited, JSON, XML… whatever gets the job done for you. So long as the values are extractable from the text using regular expressions we can log and plot the data.

3) These can either be output as a continuous stream of data that the MoM8000 software will parse, or the EUT could require separate commands to read each parameter. If you can send us an example serial output ahead of time we can get the software setup before your arrival so that no testing time is wasted during setup.

4) We also need to know what performance limits you might have (e.g. temperature deviation of +/- 0.5C) so that we can enter the appropriate limits. This notification is key as it lets us quickly evaluate EUT performance to the Immunity Criteria (A/B/C) in the appropriate standard.

 

Future Additions

We’ll be adding extra functionality to this software over time when we develop new requirements. This includes:

  • Subscribe to MQTT topics on local or remote server
  • Read HTTP data
  • Read text data file on local network
  • Tighter integration of test equipment and software to speed up EMC tests

Discuss with us in advance if you have a special requirement for testing and we will do our best to accommodate you.

1% For The Planet – Donations FY 2019

As part of our membership of 1% For The Planet we’ve made donations for the last financial year to the following environmental charities. These organisations are doing important work to preserve wildlife and habitats in the UK and around the world.

ukca mark

UKCA Mark Updates

Because of the United Kingdom leaving the EU, the CE Mark will no longer be recognised as demonstrating conformity with UK legislation.

Instead the CE Mark will be replaced by the UKCA mark (UK Conformity Assessed) which will be required to sell your products in the UK. This mark can coexist with the CE mark on the same label.

The transition period starts this coming January 2021 and UKCA marks become mandatory for the UK on 1 Jan 2022.

Whilst it sounds like a year in enough time to get everything in order think back to university and how much time you had to finish your dissertation – am I right? Start sooner rather than later, especially if you have multiple products.

unit 3 compliance ce mark to ukca mark transition

This applies to goods sold (“placed on the market” to use the correct term) in England, Scotland and Wales. Northern Ireland will still require CE marking due to the Irish border.

 

Action Stations for UKCA

You will need to create a new “UK Declaration of Conformity” similar to the EU Declaration of Conformity (which you will still need for CE marking). Contact me if you need a template. If you’ve been a customer and we’ve performed CE marking testing for you then we’ll be sending out UK DoC templates for your products before the end of this year.

The EU Technical Documentation that I’m sure you keep up to date for all your products will need an additional section with references to the UK Statutory Instruments (equivalent to the Directives) and Designated Standards. Let me know if you need some help with this.

Add the UKCA mark to your product label. You can find image files on the gov.uk website. It must be at least 5mm high.

It can be applied as a temporary label until 1 January 2023 after which it must be “permanently attached” in the same fashion as you currently apply the CE mark.

The product, or documentation where this is not possible, must have the manufacturer’s name and UK address shown. If the manufacturer is outside the UK, this must be the importer’s address.

 

UK Manufacturers Selling to EU

You are now a “3rd country” and will need an EU Sales Office (assuming you don’t already have one) whose address and contact details will need to go on the EU Declaration of Conformity. Various companies offer an “EU Authorised Representative Service” which can be found with a little searching.

If you use a UK based Notified Body, they will probably have already been in touch to discuss what is happening with your compliance certification. If not, get in touch with them sharpish and ask about your compliance status.

 

Key Dates

1st January 2021

UKCA becomes valid and can be placed on electrical / electronic products to demonstrate conformity with UK legislation.

CE mark enters transition period but is still valid for 12 months.

This transition period applies if you currently self declare CE compliance using an EU Declaration of Conformity (the vast majority of products do this).

 

1st January 2022

CE mark ceases to be valid in the UK.

UKCA mark becomes mandatory.

 

Legal Eagles

The EU directives relating to CE marking are already UK law. SI 2019 No. 696 will modify the below SIs (and more) to add UKCA marking and change the terminology. All compliance documentation must refer to these Statutory Instruments instead of the EU Directives.

Notified Bodies become Approved Bodies.

Harmonised Standards become Designated Standards and use the BS prefix (e.g. BS EN, BS ETSI EN). No list of Designated Standards is available yet, this is likely going to be published around 1 Jan 2021 where the list gets transposed from existing standards.

Most standards change at a slow pace so we’ll have to wait and see how quickly changes to the IEC, CENELEC and ETSI standards filter through to the UK standards list. Certainly no massive changes in technical requirements will happen overnight.

 

References

Guidance: Placing manufactured goods on the market in Great Britain from 1 January 2021 (Gov.uk)

Guidance: Guidance Using the UKCA mark from 1 January 2021 (Gov.uk)

UKCA information from the clever chaps over at Conformance.co.uk

 

 

Schaffner/Teseq NSG 5500 test system

New Automotive Test Capabilities ISO 7637-2

The best day is new equipment day 🙂

We are continuing to invest in our test capabilities. As such, the Unit 3 Compliance EMC test laboratory has just acquired a Schaffner (Teseq) NSG 5500 automotive surge/EFT test generator.

Schaffner NSG 5500 test systemWith this, we now have the capability to test your equipment to the ISO 7637-2 standard for automotive conducted transients.

The NSG 5500 will generate the ISO pulses 1, 2a, 3a and 3b, along with the Load Dump and Clamped Load Dump pulses 5a and 5b.

This gives us the capability to support your automotive product development to these standards:

  • EN 50498:2010 – Aftermarket electronics for vehicles – full testing for CE marking
  • CISPR 25 for non Immunity Related Function EUTs
  • UNECE R10.06 (pre-compliance)
  • ISO 13766-1:2018 Earth Moving Machinery (pre-compliance)
  • ISO 7637-2:2011 automotive conducted transients
  • ISO 16750-2:2012 automotive electrical loads (part)

 

Footnote:

Timing is a curious thing. Like two buses arriving simultaneously after a long wait I find things tend to cluster up. This acquisition occurred not long after publishing this blog post on how to test to the automotive standards without an automotive surge generator.

Rohde & Schwarz “Demystifying EMC” 2020 @ Silverstone, UK

It’s that time of year again when one of the things I look forward to the most comes around. No, not Christmas! Where have you been?

Every year, Rohde & Schwarz UK organise their “Demystifying EMC” event, organising technical training on a variety of topics as well as a compact but well formed trade show. 2020 is my third year in a row as an attendee. These last two years, Unit 3 Compliance has had an exhibition stand and I’ve been privileged to give a technical presentation as part of the training available on the day.

This year the Rohde & Schwarz team outdid themselves with record attendance causing them to have to close the registrations for the event early.

Not surprisingly the Unit 3 Compliance stand was as busy as ever with visitors from a wide range of companies and backgrounds, many new faces and some familiar ones from last year stopping by to say ‘hi’.

We also had a demonstration of the effects of poor PCB layout and it’s effect on EMC emissions being picked up by one of our near field probe kits (which flew off the table like hot cakes)

The highlight of my day was getting to deliver another technical talk – amazingly they had me back after last year! – on the subject of ground and grounding for EMC.

Rather than a list of “do this, don’t do this” I really put a lot of background work into this talk, creating images for each slide to try and illustrate clearly some of the concepts I was trying to illustrate.

I spy, with my little eye, something beginning with ‘G’

It seemed to go down really well and I had a lot of positive feedback on the day. Thank you for that, it’s sometimes hard to know if you’ve hit the mark or not. People coming up to me afterwards and saying “you’ve put into words what I’ve been struggling to say for years” and “I’ve really learned something new” makes the many hours spent on preparing this talk well worthwhile.

Whilst a “here’s-a-picture-talk-about-the-picture” makes for a great in person talk, it works very poorly as reference material after the event with just a picture and no text to go with it. So I decided to record the presentation again and push it out on YouTube. Powerpoint has a really nifty record presentation tool that can then export to a video.

So if you didn’t make it to the talk, or want to refer to the talk again, then here’s a link to the video.

Enjoy, and I’ll see you next year.

 

2018 1pftp donations

1% For The Planet Donations FY2018

As a member of 1% For The Planet, Unit 3 Compliance donates 1% of its yearly turnover (total sales, not profit) to environmental charities. All businesses ultimately profit from the planet so it is only fair that we give something back.

For the last financial year we’ve donated to the Rainforest Trust, the Orangutan Land Trust and the Woodland Trust to support work worldwide with the protection of important forest and woodland across the world.

2018 1pftp donations

James Pawson presenting at R&S EMC 2019

Rohde & Schwarz Demysifying EMC 2019

A fantastic day at the Rohde and Schwarz Demystifying EMC 2019 show down at Silverstone. It provided a chance to reconnect with some familiar faces and meet a whole load of new ones. R&S always put on a good event with varied content and lots of interest.

I was presenting a talk entitled “From Design To Pre-Compliance: Pitfalls and Pro Tips” which received lots of positive feedback from the attendees.

The weather was glorious with bullet blue skies and The Wing venue in the centre of the circuit makes for a great location.

The Unit 3 Compliance stand was very popular throughout the day with a queue of people stopping by to say hello and talk about pre-compliance testing.

The Pocket EMC Debug Probes flew off the table too.

Demystifying EMC 2018 – Silverstone

Rohde & Schwarz held this years’s instance of their excellent Demystifying EMC seminar at the Silverstone race track in the Midlands. The venue was right in the middle of the racecourse with a great view of the start/finish straight.

It was good to see so many meaty sounding technical EMC presentations on offer and my only regret was that I couldn’t split myself into two or three and attend them all. Instead, I’m going to have to wait patiently for the PDFs of the slides to come through.

In the meantime here’s a quick rundown of some salient points from the presentations that I attended.

“Practical Probing Techniques for EMC Troubleshooting” – Lee Hill, Silent Solutions

Given the relatively short amount of time, Lee gave a very condensed presentation of basic EMI issues encountered, the need for probing and the merits of different types of probes available.

He included some good explanations on the figures of merit for RF current probes and gave a compelling argument for the use of a pre-amplifier with a near field probe: “it makes all the signals look important!”

The only small disagreement I’d have with his otherwise excellent talk was his recommendation against making one’s own near field probes. I think that, with some consideration and research, it is possible to make probe sets that are just as useful as ones you can buy. I frequently use a home made capacitive field probe for debugging and actually prefer it to the one from my purchased kit. However, having the luxury of an anechoic chamber, I’m usually using the probes to chase a known frequency. Therefore I’m more interested in relative sensitivity rather than absolute calibration as I’ll already have some comparable absolute levels from the chamber.

If you get the chance to see Lee present I can highly recommend attending.

“Technical Documentation for CE Marking” – Stuart Aust, Horiba Mira

Stuart gave a brief run down of the Technical File requirements and I was pleased to find out my understanding of the requirements was aligned with his.

“Risk Assessments Required by the EMC and RE Directives” – James Daniels, Element

The EMCD and RED come with a requirement for manufacturers to complete a Risk Assessment and James gave a thought provoking presentation on how one might go about this.

Interestingly in future harmonised product standards, the Annex ZA/ZZ part will give information on what Essential Requirements of the directives that the standard gives a presumption of conformity to. This will take a while to filter into the mainstream, especially given the sometimes glacial pace of standards publishing and vested interests within standards committees.

Again, it all hinges on how comfortable a particular manufacturer is with the concept of risk. Sometimes, as EMC and standards professionals we often apply things rigorously when such an approach might not be required from the manufacturers standpoint. This is an issue I’ll be coming back to in a future blog as its something that most people probably don’t already formally complete or even consider. I shall be advising my customers on how to best complete these requirements in the future.

“Assessment of modules and EMC testing of non-radio products which include a radio module” – Michael Derby, ACB

Michael gave a thorough and practised presentation into the requirements for integrating radio modules into existing products, from the perspective of the FCC and the RED. I was pleased to find out his talk confirming my understanding of the process.

 

After receiving copies of all the other presentations, some things that stood out as particularly interesting were:

  • Real time spectral analysis for EMI debugging. I miss the real time analyser from my previous employer when I could prise it out of the hands of the RF department. I’ve had some success with replicating this using a low cost pre-amplifier and Software Defined Radio (SDR) but its not a patch on a proper instrument. The usefulness of a large real time bandwidth and good user interface is not to be underestimated and I’ve found several intra-system (platform noise) based problems using this technique.
  • Langer presented a really good look at the physical basis for radiated emissions from PCBs. I’ll be studying these slides for future ideas into debugging emissions! They also had a demo in the exhibition hall of their miniature noise injection pens which I’d be very interested to trial in future.
  • Wurth have some dense and interesting looking info on filtering for DC/DC converters. The broadband noise from these can be quite pernicious and often ends up making its way out of poorly filtered unscreened power cables.
  • Albatross Projects gave an update from the CISPR committees responsible for various product standards. Points of interest were EN 55035 making onto the RED list of standards and some small changes to test equipment for EN 55015.
  • Rohde & Schwarz had a good primer on requirements for the Radio Equipment directive from the radio testing perspective. Given the vast range of radio test equipment they make it was no surprise that this featured and who can blame them!
  • Michael Derby (ACB) also had some slides on the RED and the state of various ETSI standards. There was a wealth of info in this presentation so I shall be going through it in some detail.

All in all I was most impressed with the technical content at the seminar and will certainly be attending future events. Thanks to the Rohde & Schwarz for putting on such a good event.

 

An Important Balance

Here at Unit 3 Compliance, we recognise that the industry we primarily work in, electronics, has environmental consequences caused by the production, use and disposal of electronic products and systems. Many electronic components are highly complex and not easily recyclable. Energy usage of electronic products is massive. Waste electronics, if not disposed of correctly can cause an environmental hazard, never mind the associated plastics and other components.

We only have one planet to live on, to pass on to future generations and we feel strongly that we cannot shirk our responsibility to the environment. That said, the ability of an individual or small organisation to make significant changes to society and the environment is difficult. We have taken action to try and redress the balance and to attempt to lessen our impact on the environment.

We try to minimise the amount of waste we generate but, where we do, as much of it as possible is recycled. Given the amount of tea we drink, this adds up to a lot of composted teabags!

We have moved our electricity provider to Ecotricity who reinvest their profits into building windfarms and bio-methane mills.

Most importantly for us, we have become a member of 1% For The Planet. In doing so we have committed to give at least 1% of our sales turnover (not profit) every year to environmental charities who are on the front line of trying to make the planet a better place. Reading Yvon Chouinard’s book “Let My People Go Surfing” that tells of his environmental commitments as CEO of Patagonia Inc. was a significant influencing factor in this decision.

We look forward to playing our part.

log periodic christmas tree

Have an anechoic Christmas!

The office tree is up!

Wishing all the customers, suppliers and friends of Unit 3 Compliance a very happy Christmas and a prosperous New Year.

“Oh Christmas tree, oh Christmas tree

Your branches grow,

Log periodically…”


log periodic christmas tree