Making light work of machine safety
Increasing global competitiveness drives the continuing efforts to reduce the production cost of manufactured goods through techniques such as ‘Just in Time’ and ‘Lean Manufacturing’. But, however plants and factories are organized and however often they are re-organized, safety cannot be compromised. Protecting personnel from machine hazards need not be a costly affair, but it does require highly reliable equipment. With the advent of powerful and low cost LEDs, together with easily programmable control electronics, safety light curtains can be conveniently configured to match a wide variety of machines, and efficiently reconfigured when necessary. This article will outline recent technological advances in safety light curtains. Higher light intensity, smaller packaging and easy control are important aspects, but variable range/resolution, long life, high reliability, and especially low cost, are making safety light curtains a more compelling choice in many applications. Specific reference will be made to models in the F3SG range from Omron Automation and the SF4D range from Panasonic Industrial Automation Sales.
Invisible light On its website, Omron has provided informative and technical data on the operation and application of safety light curtain products1. In its simplest form, the industrial safety light curtain consists of optical transmitters and receivers used to detect swiftly any object that breaks the light barrier. A signal is sent to stop any hazardous machine movement instantly within the protected area. The light curtains typically incorporate photoelectric transmitters in the form of infrared LEDs, which project an array of synchronized, parallel invisible (infrared) light beams to the receiver unit. The light beams are sequenced and modulated to pulse at a specific frequency. The receivers are programmed to detect only the pulses emitted at the designated frequency, thereby avoiding interference from other light sources. Safety light curtains can be configured to meet a wide variety of applications, providing different levels of protection across different distances and resolutions. There are three broad categories: point of operation or pinch point (guarding a specific machine or operating area of a machine); perimeter guards (protecting a robot work cell, for example); and area guards (effectively an optical fence).
Written by: European Editors Contributed By DigiKey's European Editors
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