Industrial indicators: less heat, more light
18 December 2012
In 1840, British astronomer and chemist, Warren de la Rue, enclosed a platinum coil in a vacuum tube and passed an electric current through it, thus creating the world’s first light bulb – a full 40 years before Thomas Edison was issued a patent for creating it.
Light emitting diodes (LEDs) first appeared as a practical electronic component in 1962 but had a very low intensity output. By 1970, photoelectric sensor manufacturers started to use LEDs as an alternative to incandescent bulbs because they lasted longer, even though they had only about 1 percent of the latter’s light intensity.
Then photoelectric sensor designers discovered that the LED had a benefit far more profound than its long life; unlike their incandescent equivalents LEDs can be turned on and off at high frequency, typically several kilohertz. This property meant that the receiver could be tuned, like a radio, to the frequency of the LED emitter.
A number of engineers pioneered modulation methods and applied these to industrial photoelectric controls, among them Robert W Fayfield, the founder and CEO of the US company, Banner Engineering. In 1974, Banner introduced the first self-contained, modulated, visible LED sensor and by 1978 had released its Multi-Beam sensor range.
More recently, the company has used its high IP rated LED enclosure expertise in the development of a whole new range of products – lighting, panel indicators and signal towers. Indeed, this new enterprise is faster growing than the sensor side of the business in terms of product innovation and turnover.
On the lighting side there are two product areas: ‘Vision’ and ‘Task’. Vision lights are a complete range of rugged, maintenance-free, high-intensity LED lighting in red, green, blue, white and infrared. They feature built-in universal strobe control and power regulation, and there’s a complete range of polarising filter kits, coloured filters and lighting diffusers to fulfil all the requirements of the machine vision industry.
Task lights provide an industrial alternative to fluorescent and halogen bulbs in enclosure, area and machine lighting, where they consume just a tenth of the energy of conventional lighting to illuminate the same area, as well as having a life in excess of 50,000 hours. Suitable for wet and dirty environments (housings rated up to, and including, IP69K), Task lights are constructed from materials that are acceptable in food and beverage processing areas.
Indicators that provide direct replacements for conventional panel and tower lights and actuators combining sensors and indicators make up the rest of Banner’s new offering, but with all the advantages of LED technology, including maintenance free 100,000 hour continuous working life.
A single indicator can display up to five different colours and these can be glowing, flashing, sequenced flashing, strobing or rotating. Thirteen styles are available including tower and column lights, segmented displays, daylight visible for outdoor applications and traffic lights. All models are rated to IP67 or IP69K and some are also available with audible alerts.
The actuator products are suitable for manual part picking from bins on assembly lines and provide operator guidance and feedback in a single unit. Briefly, the indicator tells the operator which part to select and the sensor detects that the operator has taken the correct part. If an incorrect part is selected the indicator will change from green to red and the control system will be alerted.
In a typical error proofing solution for bin picking or sequential assembly, the operator is positioned in front of a storage rack consisting of many trays of component parts. Each of these ‘pigeonholes’ will have a part verification device positioned across the opening. The controlling system guides the operator through the assembly sequence by signalling a part verification device to illuminate its large ‘pick indicator’, which will turn bright green. When the operator reaches into the tray to take a part, their hand is detected by the part verification device, which sends a signal to the controller to indicate that the part has been taken.
The controller responds by switching off the indicator on the picked tray and illuminating the indicator on the next tray in the sequence. If the operator reaches in to the wrong tray at any time, the indicator on the part verification device for that tray will illuminate red and a signal will be sent to the controller that an incorrect part has been picked. This ensures that an error is detected and can be corrected immediately. The system also facilitates rapid change over to a different product. The controller simply runs another component selection sequence, guiding the operator to a different set of parts.
Providing a clear indication of status, even at a distance and in bright conditions, Banner’s LED range – Vision, Task, or Indicator – can be mounted directly on the machine, thanks to their high IP rating and robust construction, thus avoiding the need for an extra panel or enclosure. And there’s a complete line of brackets, including versions for common racking profiles, to help you achieve an optimum mounting position.
All these products, including custom assemblies, are available from Turck Banner in the UK on a fast order-to-delivery basis.
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