Hello Martin, It depends on what your end user is using the PLC for. If it is used in a safety circuit then functional aspects are considered critical as well as safety aspects. EN 60204, which is one of the main standards used for machinery, specifically calls out in cl. 12.3.1 that "programmable controllers shall comply with relevant IEC standards (see IEC 1131)".
When testing a machine I would not accept a CE marked PLC, only a third-party marked version, and only if all of the applicable parts of the standards were tested. The LVD should be used for end-product systems, not components, and safety critical components (like e-stop switches or PLCs) should meet the requirements of their relevant component standards. Patty Elliot TUV Rheinland of N.A. Personal opinions, not corporate At 05:17 PM 6/11/97 +0900, Martin Ginty wrote: >Sorry about the previous attempt!! I hit the send button by accident! >********************************************************************* > >Dear All, > >hopefully one of you out there can help me with this, > >My company has recently been contacted by an organisation stating that >our product (programmable logic controller) should comply with the >requirements of EN61131-2 (the standard for programmable logic >controllers) as it is listed on the OJ for the Low Voltage Directive. No >problem with that, we already comply with the safety aspects of this >standard. However, they also think that we should test to and satisfy >the functional requirements as well as the safety requirements. To my >knowledge LVD is concerned with the safety of circuits operating at >voltages above 50VAC or 75VDC. The directive states that the safety >requirements only need to be met and most of the standards listed on the >OJ for this directive are applicable to the safety requirements portions >only. Also at the beginning of EN61131-2 it states that this standard >takes precedence over all other standards EXCEPT basic safety standards. >EN61131-2 isn't actually a safety standard as such, it covers design and >definition of PLC systems as well as design requirements for circuits >operating within the voltage ranges that fall within the scope of the >directive (and a whole bunch of other stuff I don't want to go into!). >However, as many of the circuits within a PLC system are SELV they don't >fall within the scope of the directive. > >Is there any justification for this organisation to demand this? >Am I missing something here? > >Best regards > >Martin Ginty >Mitsubishi Nagoya Works >FA systems department >
