Light curtain in new simplified configuration
29 September 2009
SICK says it is ‘extending the frontiers of light curtain safety performance’ with the launch of the miniTwin 4. For the first time, sender and receiver elements are combined in a single miniature housing.
What this means is that the miniTwin elements are available separately. Conventional light curtain elements are always sold in pairs, one a sender, and the other a receiver. They are ‘tuned’ to each other. With the miniTwin, instead of stocking pairs of senders and receivers, the end user only has to stock one type of unit, the combined sender/receiver.
The diagram shows one miniTwin with four senders and four receivers paired with an identical miniTwin rotated 180 degrees..
The photo shows four miniTwins in total, two connected end-to-end on each side. Each miniTwin has 15 sending units and 15 receiving units. (We have rotated the photo 90 degrees. The miniTwins are normally installed in a vertical configuration, so that the light beams are horizontal.)
Solves certain problems
SICK safety specialist Seb Strutt says the miniTwin’s capability solves applications where traditional light curtains would be too big and awkward to install, and ‘do not offer as much value for the performance.’
The new modular units are available in lengths from 120mm to 1200mm. For odd lengths, or longer lengths, they can be cascaded or daisy chained end-to-end up to a total of 3600mm without any blind spots. Rapid response times permit safety monitoring with reduced reach distances for operators and therefore smaller machine footprints. Mr. Strutt says the field coverage is continuous between adjacent units without loss of resolution or requiring special mountings or physical protection between curtains.
The miniTwin 4 units may be configured to protect L- shapes, V-shapes or even U-shapes, combining easy access to a work piece or to change tool bits or jigs, while offering complete protection. They are ideal where all round accessibility and visibility is required which is otherwise restricted by fixed barriers. Variable field lengths are possible to suit locations.
Each miniTwin 4 unit includes the inbuilt controls and LED status indication, which means any two identical units operate as a light curtain, without any requirement for an extra control unit. This means spares can be stocked as single units rather than in send/receive pairs.
The range is up to 4 metres. The units themselves are 15mm by 32mm cross-section and have a choice of three object resolutions from 14 to 34 mm.
Configuration and alignment tools are automatic and built in, with full status and diagnostic LED displays. The universal fixing brackets ensure rapid secure installation, for instance to standard aluminium profile, and the rotating connector with standard M12 5-pin plug will accommodate any orientation.
The miniTwin 4 is designed to meet performance level pl e according to EN13849-1, or alternatively SIL3 in compliance with IEC 61508 or the sector standard EN62061.
In 2009 the miniTwin 4 has won the reddot and IF design awards in Germany.
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