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How to Select Industrial Products Blog

How to Select Industrial Products

This is the place for engineers to learn about and teach others how to select industrial products. The blog is maintained by the Editorial team at IEEE GlobalSpec, the company that powers CR4.

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Trying to Find 'Fabulous' Light Curtains

Posted April 01, 2013 6:05 AM by HUSH
Pathfinder Tags: how to select light curtains

I really wish they would make light curtains available in more colors, don't you?

Their appearance always clashes with the machinery. The silver and black parts picker looks HORRIBLE next to those yellow light curtains. Some people say black is neutral--but me, honey please! Don't even get me started on these orange coveralls! I say there is nothing wrong with being fabulous while also doing a little hard work.

So is the life for that fashionably-perfect in the manufacturing world. However, those light curtains do keep this tight tush nice and safe.

A light curtain's main advantage is that it does not impose a physical barrier on personnel. As such, an operator is able to access guarded components without mechanical or observational limitations. Maintenance processes are also eased by their use. Light curtains can be used to monitor cargo in or out of a restricted access area, as well as provide strictly one-way access.

A transmitter is established and an array of parallel infrared beams provide a boundary across the restricted access point. The transmitter can emit its rays in virtually any configuration provided the infrared beams conclude at a receiver. Mirrors are frequently used to relay beams around corners or obstacles which reduces the need for multiple transmitters, but for every mirror the beam range is reduced by 25%. An alignment laser or LED indicator is frequently integrated in the transmitter for accurate positioning. Manufacturers may elect to incorporate light curtains in standalone machinery and these devices will have increased sensitivity. Light curtains have variable and convenient installation patterns.

The infrared light beams are sequenced and modulated and the receiver is designed to recognize a specific infrared beam, decreasing the chance for issues from ambient infrared light. When a beam is obstructed by an opaque object, a safety relay halts the machinery or process within milliseconds. Some light curtains allow the process to resume once the obstruction is removed, while others require an operator to manually restart the process. A PLC (integral or external) is required for the light curtain to interface with the machinery it encloses. A timed mute feature allows operators to control the flow of materials through the perimeter without stopping the machine. Some muting scenarios allow the passage of humans, while if other muting sensors register a human or irregularity then the process will cease.

And while it may not be available in say, polka dots or glittery pink (my fave!), many light curtains offer much more important features. Self-checking circuitry has the capability to run a self-check during startup, operation, or continuously to ensure no loss of function. Latching safety relays will not remove the stop signal until the controls are manually reset outside the protected area. And muting is the temporary, automatically controlled deactivation of a safeguarding device during the non-hazardous portion of the machine cycle.

Anyhow, you can learn all about light curtains at the GlobalSpec Light Curtain Selection Guide. And though the search filter doesn't have a category for color, it can be useful for some other solutions.

Excuse me, time for lunch with the boys from floor 3 . Ciao!

(Images credits: Southern Industrial Equipment; Industry Direct)


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Join Date: Dec 2010
Location: North West England
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Re: Trying to Find 'Fabulous' Light Curtains

04/02/2013 4:39 AM

You have obviously not understood the concept underpinning the colours yellow and orange in the workplace. A major part of the training of fork lift truck drivers involves teaching them not to hit anything that is yellow or orange. All other colours it would seem are fair game. I have seen fork truck scivers drivers take out walls, door posts, mezzanine support columns, other fork trucks, parked cars, lorries, fork truck battery chargers and many other industrial items. Light curtains are expensive. Painting them blue or pink (with or without dots) renders them more vulnerable to destruction.(No system is perfect where fork truck drivers are concerned, but putting things on the second floor with only a pedestrian stair access is a fairly good option)

Note to the editor, since the change to IHS, my emoticon and symbols buttons on the toolbar are broken. (I use Firefox)

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Re: Trying to Find 'Fabulous' Light Curtains

04/03/2013 7:16 AM

Do a hard refresh (CTRL + R) and your symbols and emoticons will work once again.

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