“Visitors are requested to turn off mobile phones when in this hospital.”
“All devices must be turned off during take off and landing.”
It’s a bore, but we have to do it, and the risk is that our phones will somehow interfere with their electronics. And that’s the last thing you want, or for a large robot to go berserk because of electrical corruption…so there has to be a control on the amount of interference, “noise”, that all electrical and electronic machines emit, it makes sense.
The trouble is that EMC is still viewed as an expensive process that is not really required, and this article identifies the real need for EMC and how the cost of meeting EMC requirements can be kept to a minimum.
Electro Magnetic Compatibility, EMC. means the ability of modern electronic equipment to function properly within the electrical environment that exists today, both from the point of view of withstanding ‘noise’ from other equipment (Immunity) and not itself generating excessive ‘noise’, (Emissions) to create interference with the devices around it. It’s important that electrical and electronic devices are able to cope with low signal conditions, high levels of noise and still function as required.
It doesn’t take much imagination to see how, in today’s industrial environment and with lots of heavy electrical and electronic devices all working in close proximity, it becomes vital for EMC to be adhered to. There’s also a legal requirement to ensure that all products conforms to the current European Directives and associated Standards, it’s an important element of CE marking and a complete set of test results and information must be provided within the Technical File.
So, how can we help?
This type of noise uses some complex test equipment to measure it and produces information that requires an experience engineer to interpret the results. Interestingly experience shows that most of the costs associated with EMC testing are caused through not getting things right in the first place and all the work involved in fixing faults and retesting. It doesn’t have to be like this, and we’ve prepared the following list as guidance:
1. Ensure that an experienced EMC engineer look at all designs prior to manufacture and that their advise on potential problem areas and actions to take are acted on. If this is done at the design stage the cost is low but the end results prove very cost effective.
2. Use CE marked components.
3. Always follow the manufacturer’s installation instructions.
4. Have experienced engineers design and build the equipment, keeping power and control cabling separate, do not cross input and output signals, ensure good earthing practises, etc..
5. If possible perform mini uncontrolled tests on products at the pre-production stage to check if any problems are likely, reducing the potential for issues before production starts.
6. Always aim for large margins of clearance from legal limits to actual performance to allow for slight variations in component specifications.
7. On high volume products carry out regular tests during production. By the time a complaint is made it’s generally is too late and expensive to remedy.
8. Prepare and record proper tests results to be included in your Technical File.
Needless to say, IES can provide advice at all stages of manufacture; we can undertake any testing and provide appropriate and full test results.
Please contact IES if you require any testing, manufacturing support or assistance with the compilation of the technical files.