Frequently asked questions
at EMI Test Lab
Yes you can. For the FCC everything other than intentional radiators, such as Bluetooth and WiFi, falls into a new category called Suppliers Declaration of Conformity. This new category no longer requires accreditation for the lab or manufacturer to declare compliance with the FCC standards.
The CE mark has always been modeled as a self-declare type of process, just took the FCC 20 years to catch up. We can provide all the testing and reports you would need to self-declare to most CE standards.
A little technical background – Our chambers are based on a free space model which is the fastest way to take radiated emissions data. Semi-anechoic chambers need to search in height from 1-4 meters to find the highest signal level at each frequency. With a Fully Anechoic Room (FAR) or a GTEM the max signal level is captured without the need to raise and lower a receiving antenna. This also gives you a true A-B comparison between scans for troubleshooting purposes. Because we don’t need to search in height the full sweep from 30-1000 MHz is roughly 20-30 minutes compared to 1.5 to 2 hours in a Semi-anechoic chamber where you need to raise and lower an antenna to get the max amplitude level at each frequency. The FAR and GTEM also have a much lower measurement uncertainty than the Semi-anechoic chambers. This makes the data in a FAR or GTEM more repeatable from scan to scan.
So for four hour blocks of time or more we charge $375 per hour. In one hour you can get two sweeps from 30-1000 MHz, max amplitudes across the spectrum, for roughly $150 per scan. Our competitors charge on average $450 per hour and it takes most of the 2 hours to get 1 scan from 30-1000 MHz – and the data is not the max amplitude at all frequencies making it more difficult to compare A-B troubleshooting scans.
So, one of their scans, $700-900. One of our scans $150 and you have total radiated power – max amplitude levels at all frequencies across the spectrum. Our chambers meet all the required calibrations by the FCC and CISPR for CE.
For most products you can use the new Suppliers Declaration of Conformity route for FCC compliance, for SDoC you do not need to use the big expensive labs. You can use any well qualified lab or even take the data yourself. If you are designing a Bluetooth or WiFi radio from scratch (you must have sales in the 10’s of thousands per year to justify not using a pre-approved module) then you need to use a lab that is accredited for intentional radiator certification, for final data. We can still help with pre-compliance and design mitigation.
For most products EMI Test Lab can do all the testing for CE and write a report, help you with a Declaration of Conformity document, labeling and user guide statements.
If you have a product that is very unsafe from a product safety point of view – circular saw, manufacturing machine that can hurt someone, electrosurgical generator, etc., then you need to use a Notified Body for product safety. If you fall into these types of categories then you can’t self-declare. You can use us for pre-compliance but the final data should be at labs associated with the Notified Body you are working with.
Yes we can. And we can do final Compliance for most products.
Pre-compliance is testing that you can do early in the design cycle in order to determine if there are circuit level changes that need to be made in order to pass the final testing. Guys that have had the bad experience of failing FCC radiated or conducted emissions at the last minute when the product is supposed to be shipping don’t need to be convinced that this is a smart thing to do. As soon as your product can run any level of functionality you should get a quick look to see if you are in the ballgame or if there is a re-design in your future. Another good reason to do pre-compliance is to see if that power supply you are going to buy thousands of is really compliant with the standards they claim. The bigger companies are usually ok but if you are buying a semi custom supply or got the supply cheap from China you should find out if things are ok before you buy thousands.
Pre-compliance is cheap insurance. Especially if you take advantage of our low prices.
If we see any issues we will give you guidance on how to solve it.
The main difference between FCC testing and CE testing (for EMI) is that the CE Mark requires immunity testing ( your product’s ability to reject Noise) the FCC only requires emissions testing (the frequency noise that your product puts out into space).
Just as for the FCC, there should be a quick radiated and conducted emissions sweep, the standards are harmonised so pass the FCC and you pass CE. The main difference is that we run the unit on 230 VAC 50 Hz for the CE testing. If the product makes small measurements such as lab equipment then it may be suseptible to radiated and conducted immunity. We can do a shortened version of radiated and conducted immunity in about 2 hours.In general, if you have a good power supply then surge should be ok. The test that most people have issues with is Electro Static Discharge (ESD). We can do a quick ESD test at the highest levels in about 30 minutes or less that can usually flush out any issues you are going to have with ESD. If you do have issues we can suggest changes that will probably fix the issue. Some products have issues with EFT (Electrical Fast Transients), it’s a short test so it’s worth taking a look.
So a quick test plan may look like:
1. Radiated and conducted emissions – EN 55011 or EN 55032 for most products
2. ESD, quick test – EN 61000-4-2
3. Radiated and Conducted Immunity – quick test – EN 61000-4-3 and EN 61000-4-6
4. EFT, quick test – EN 61000-4-4
Doing these tests before you need to ship the product, as pre-compliance, can save you lots of time and money
The first part of doing a quick pre-compliance test plan would be to talk to an EMC Engineer to make some Engineering judgement calls about which tests are the most likely to affect your equipment. All the EMC tests are supposed to resemble something that may and actually has actually happened in the real world.
The 4th edition of the IEC 60601-1-2 standard has some changes that are likely to fail products that met the 3rd edition. For example, home use products now need to meet 10 Volts per meter radiated immunity when they only had to meet 3 Volts per meter for the 3rd edition. ESD testing is now up to 15 kV air discharge from 8 kV in the 3rd edition. Contact discharge is up to 8 kV from 6 kV. I/O connector pins may also be subjected to ESD zaps when in the 3rd edition we didn’t touch them. There’s also a new list of radiated immunity frequencies listed in Table 9 that are tested at levels as high as 27 Volts per meter. The 3rd edition maxs out at 10 Volts per meter.
If you wait to find out if your medical product can meet these new requirements until you are doing your Certification Testing at the big expensive labs you are in for a big surprise, project schedule delays and lots of explaining to your manager.
We can do a sub set of the IEC 60601-1-2 4th edition testing that is likely to flush out any design issues. We can also suggest design modifications that will probably fix the issues. Our lab is completely stocked with the items you will need to fix the issues.
The first part of doing a quick pre-compliance test plan would be to talk to an EMC Engineer to make some Engineering judgement calls about which tests are the most likely to affect your equipment or the certification of the module. It’ll probably come down to re-checking the fundamental and the harmonics in your system. You will probably need to get special software to test the module in a “no modulation and check specific channels” mode. Check with the manufacturer for this special software.
For the FCC you need to pass radiated and conducted emissions. The upper frequency limit of radiated emissions is based on the highest frequency or data rate you generate. For most projects the problems are in the 30-1000 MHz range, for radiated emissions. Bad or power supplies with little or no ac power line filtering fail in the 150-500 kHz range. Also read “How to get the CE Mark”.
For the CE Mark for Europe we need to pass immunity tests as well as Emissions Tests. Here are the most common for the EMC Directive:
1. IEC which is the same as EN 61000-4-2: ESD (Electro Static Discharge). 4 to 8 kV Contact and 8 to 15 kV Air Discharge depending on the Standard you are testing to.
2. IEC / EN 61000-4-3: Radiated Field Immunity from 80 MHz on up. Usually we stop at 1 GHz but go as high as 2.7 GHz for Scientific Lab Equipment. For Medical Equipment we spot check transmitter frequencies as high as 5.8 GHz.
3. IEC / EN 61000-4-4: Electrical Fast Transients or Burst Testing. The Military came up with this test a long time ago, they called it the “Chattering Relay Test”. These tests are supposed to resemble the pulses that are applied to the Power Line when a relay opens and closes, when the contacts get close but don’t touch. Applied to the AC and IO lines 3 meters long or greater.
4. IEC / EN 61000-4-5: Surge. Supposed to resemble a nearby lightening strike. Applied to AC Power and Long Long Lines, and also Ethernet that runs outdoors, might be exposed to Lightening Strikes.
5. IEC / EN 61000-4-6: Conducted Immunity, typical from 150 kHz to where Radiated Immunity starts at 80 MHz. Applied to the AC and IO cables 3 meters and longer.
6. IEC / EN 61000-4-8: Power Frequency Magnetic Field. If you have components that are sensitive to low frequency magnetic fields this is a test for you. Applied around the entire system.
7. IEC / EN 61000-4-11: Voltage Dips and Short Interruptions. This resembles “Brown Out” conditions. If you have lots of capacitance in your power supply don’t worry much about this test.
There are also a couple of Emissions Tests that the EU wants you to do, they are:
1. EN 55011 or CISPR 11: Emissions Tests for Medical, Scientific Equipment and Industrial equipment.
2. EN 55032: ITE Equipment, Information Technology Equipment, basically computers, laptops, audio, data center, etc…
3. Also AC Harmonics and Flicker for some applications, and depending on where the equipment is used, residential or commercial and whether or not the equipment has an intermittent or steady state current draw.
The test for AC Harmonics is IEC / EN 6100-3-2, the test for Flicker is IEC / EN 61000-3-2.
These are the most common tests, the test levels differ depending on the Standard and the Environment where the equipment is used.
Also read our paper on “How to get the CE Mark”
If the Test is Pre-Compliance and it’s the first time you’ve been to an EMI Lab, please communicate with someone at the lab or please come by for a lab tour.
1. If you’re doing pre-compliance have the unit running as it typically runs in the real world. This usually means all IO cables attached and transferring data on all lines.
2. If you’re doing a Class A product (commercial) you can have the support equipment out of the chamber if you bring at least 15 feet of IO cables to set equipment outside the test area.
3. If you’re doing a residential project you need to be prepared to have all of the support equipment in the the test area. This is not as easy as it sounds , a LOT of equipment being sold as Class B (Home Use) has little or no margin and may even FAIL because of measurement uncertainty and site to site variability. Get good support equipment to Pass your project. The idea is you are also proving that you are not causing a product to fail by connecting to you. If you need ideas of good products, get a hold of us, we know what types of products have a better chance of passing.
If you have any questions on test setup don’t hesitate to ask ahead of coming into the lab for testing.
4. If you are doing final testing we need to fill out a Test Plan before we begin. This Plan should answer questions that you may have before we begin testing.
Depends on which test and how complicated your product is to set up and run.
- Radiated emissions from 30-1000 MHz takes about 20-30 minutes. Can take as little as 15 minutes if you don’t care about quasi peak measurements.
- AC power line conducted emissions measuring both line and neutral takes about 45 minutes to an hour.
- ESD – IEC 61000-4-2, Electro Static Discharge depends on the size of the product and how many test points we have. The average product takes between 2-3 Hours for a full test.
- Radiated Immunity – IEC 61000-4-3, takes about 3 hours from 80 MHz to 1,000 MHz, all four sides, Vertical and Horizontal transmit Antenna polarizations. There are also tests from 1 to 2.7 GHz and above for Medical equipment, these tests take a couple of hours.
- EFT, Electrical Fast Transients – IEC 61000-4-4 takes only a half hour or so after the test setup which take about another 20 minutes or so. If you have any IO cables that are 3 Meters or longer, such as Ethernet, you need to do this test on the IO Cables as well.
- Surge Immunity Testing, IEC 61000-4-5 used to take 5 or 6 hours because the Standards had us apply the pulse to the AC line at 0, 90, 180 and 270 degrees, 5 pulses at each using a positive and negative pulse, with at least a minute between each pulse. But now the Standards are all a little different but they cut down the test time anywhere from an hour to 2 or 3 hours or so. If you have a good power supply, you’ll probably pass this. All the new good supplies are designed for this test (or they won’t sell very many!).
- Conducted Immunity Testing, IEC 61000-4-6 is tested on the AC power lines and IO lines that are 3 Meters or longer for most standards. This test after setup takes less then an hour from 150 kHz to 80 MHz.
- Power Frequency Magnetic Field Testing, IEC 61000-4-8 takes less than an hour after setup.
- Voltage Dips, and Voltage Variations, IEC 61000-4-11 takes less than hour after setup.
- For FCC if all we have to do is take data we have about a 1/2 day to take Radiated and Conducted Emissions
- For the CE Mark the Average Product takes about 3 1/2 days for all the Testing
For the standard rate lab charge we charge $375 per hour. That price includes the Lab a Technician and advice from an Engineer. We don’t charge extra for Engineering Design advice. Most Labs charge the same or more and it doesn’t include any advice to help you get your product passing.
For the FCC we charge by the Product, anywhere from the Min of $1,500 to $3,000 for a typical product.
For the CE Mark anywhere from $2,400 to $6,500 for a typical product depending on which tests apply and how many modes of operation we need to test.
FCC reports are $800, CE Reports are $1,200.
Yes. We want you to be successful so we will help any way we can. If it makes more sense for you to do experiments back at your lab we will help you do that.
Very Well. We correlate to NIST (National Institute of Science and Technology) in Boulder, NTS here in Longmont and HP’s 10 Meter Chamber in Ft. Collins, plus or minus a couple of dB or less. Standard Deviation is WELL within the 4 dB allowed by the FCC.
Our Chambers also meet the requirements of CISPR 16-1-4 and IEC 61000-4-20.
Yes!! Just bring it with you or give us the numbers over the phone.