New! - Norman Equipment Co.

Introduction – Optoelectronic safety sensorsEN 61496The field of automation issubject to a permanent andinnovative change of productsand applications. The focus ison increasing the productivityand realising a smoothrunningproduction processwith a minimum of humaninterventions on machineryand systems. The ideal, a fullyautomatic and totally safemachine however will alwaysremain a dream, though therobots used in productionplants already are a big steptowards this aim.Human intervention andknowledge will always berequired for thecommissioning, monitoringand maintenance of modernindustrial systems. Manhowever is not infallible andignorance or lack ofinformation, thoughtlessnessor negligence often leads todamages.For these reasons,harmonised standards, i.e. theMachinery Directive EC98/37/EC and otherregulations, wereimplemented at Europeanlevel.These standards aim atdetecting and constructivelyavoiding all possible risks andhazards during the planningand project phase ofmachines and systems. Safetycomponents must be used tominimise or eliminate theresidual risks.In this way, manufacturers andusers are making equivalentefforts to set up an optimalprocess flow, which offers thehighest possible protection tothe operating staff. Thechallenge for allmanufacturers of safetycomponents is to designefficient and safe productsolutions for mechanicalengineers. Flaps and doorsare the simplest means ofaccess to the machine.These separatinghardguarding safety solutionsoffer an efficient and effectiveprotection against hazardousmovements and productsbeing ejected from themachine.When these safety guards areopened, the machine isbrought to standstill (throughthe corresponding safetysensor transmitting the “stop”signal to the control), whichinterrupts and therefore slowsdown the production. In caseof continuous processes,which must not beinterrupted, solenoidinterlocks protect man and thework piece against damages.Safety fences are not suitablefor production processesrequiring the material to betransported into the workingarea by means of conveyorbelts, as it does not allow foran ergonomic and optimalwork sequence.A “virtual safety guard“ in theform of an activeoptoelectronic device (AOPD),e.g. a safety light curtain, is aperfect solution, offering bothan optimal protection ofhuman life and uninterruptedproduction process.266