Declaration of conformity to EMC Directive

Question

We need to declare CE compliance of a system consisting of pumps, valves, sensors and control cabinets. I am dealing with the EMC element of the certification.

I have collected the manufacturer's declarations for all the components, to see if harmonized standards were used and therefore if a presumption of conformity exists.

For the control cabinet components this was no problem.

But the pumps (e.g. MegaCPK from KSB) and pneumatic actuators (e.g. 3277 from samson) are certified via the Machinery Directive. These specify in their manufacturer's declaration e.g. Guide to application of the Machinery Directive or the standards ISO 12100 and EN 809, but no standards of the EMC directive.

Is this equipment therefore not EMC compliant or is the EMC Directive already complied with by the standards of the Machinery Directive or is this equipment not covered by the EMC Directive at all?.

The same question arises for me for pressure operated valves and pressure/flow/temperature sensors, which are certified according to the Pressure Equipment Directive and do not have harmonized standards of the EMC Directive.

Thank you very much for your help!

Answer 1

If you are providing a complete system, made up of parts, then it is not sufficient to simply rely on the EMC certification (or not) of the constituent parts. EMC behavior will depend on things like the wiring used between elements, grounding scheme, nature of enclosure, etc.

The most you can say is that using elements which are EMC compliant will give you the best chance of achieving an overall EMC compliant system. You can't just assert EMC compliance based on EMC compliant parts.

Answer 2

FAQ: You cannot get a CE marked product by putting together various parts that are individually CE marked, period.

Neither the EMC nor the Machinery directive works that way. Therefore you have to CE mark the resulting product against both EMC and Machinery directives. And whoever places the end product on the market has to do that as well.

Whether or not actuators, electric servos, solenoids, electrical modules etc have to CE mark against the EMC directive too, depends on if the product is to be regarded as just a stand-alone component which cannot do anything meaningful on its own. Whereas stand-alone system-level components (like a PLC) and/or partially completed machinery (like a valve rack complete with e-modules) need to CE mark against EMC and Machinery directives. Article 2 of the EMC directive 2014/30/EU says that the directive does not apply in case:

(i) it is incapable of generating or contributing to electromagnetic emissions which exceed a level allowing radio and telecommunication equipment and other equipment to operate as intended; and

(ii) it operates without unacceptable degradation in the presence of the electromagnetic disturbance normally consequent upon its intended use;

(The Machinery directive will have similar text but only concerns itself with whether or not the product is safety-related or not.)

For example electric servos, solenoids, motors etc are known to generate significant reverse EMF when energized and the best practice to remove that spike is to place a freewheel diode across the coil, as close to it as possible. These won't be delivered with the hydraulics, but have to be provided by the one designing the electrical control system.