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New sensor generation from Leuze electronic

New sensor generation from Leuze electronic

10 February 2008

Sensors from Leuze electronic are renowned for extraordinary performance. A new generation of sensors has now been launched which encompasses a variety of standard series. Technological advances and new production techniques offer maximum functional reliability and handling convenience coupled with an optimum cost-to-performance ratio.

Leuze: Sensors intended for industrial production and automation applications are required to comply with wide-ranging requirements. They must be hard-wearing and also function reliably in the most hostile environmental conditions. At the same time, applications in the field of production process automation pose ever new challenges in terms of the quality and efficiency of optoelectronic sensors. Product miniaturization, faster and more precise detection, interference from spurious light sources, reflective packaging and tough environmental conditions involving heavy soiling or intensive cleaning cycles are only some of the challenges facing modern sensor technology. Given the increasing complexity of applications, for instance modern material flow and logistics systems in which often hundreds if not several thousands of sensors are deployed to ensure a troublefree sequence, product features such as fast, easy commissioning and handling simplicity are gaining enormously in importance. Development work on the new photoelectric sensor generation focused on reducing life cycle costs, in other words achieving lower costs in terms of procurement, commissioning and operation.

New production methods and advanced technology

By launching its new sensor generation and executing a complete redesign, Leuze has succeeded in creating a product range with an enormous performance versatility from what is practically a single “mould”. The three size categories 3B, 25B and 46B afford mounting compatibility with all commonly used designs. An oblong hole permits flexible adjustment, and the new tough-look styling delivers extreme seal tightness (IP 67 and IP 69K) as well as a high degree of stability. Alongside improved performance reserves for reliable object detection even in dusty atmospheres or with high adjustment tolerance levels, other characteristic features of Leuze products include technologies such as active and spurious light suppression or “brightVision®”. This technology is known as Active Ambient Light Suppression and is abbreviated to A2LS. It allows optosensors to recognize the incidence of spurious light and to distinguish between its own sensor signal and the interference source. If an interfering signal is detected by the sensor close to the frequency or phase range of the sensor signal, it changes the phasing and frequency of its own signal within an extremely short response time. This largely eliminates any susceptibility to interference from pulsed light sources, for instance from energy saving lamps.

This type of sensor also permits the realization of applications in which several sensors use one and the same reflector, for instance in order to scan the positions of a load. “brightVision®” is a technology which substantially simplifies the handling and commissioning of sensors. Of primary importance is their simple alignment with the aid of a bright, easily visible light spot. Bright display diodes with easy all-round visibility also make for more convenient operation. A maladjusted or heavily soiled sensor draws attention to its condition over large distances by emitting a flashing signal visible from every angle. Operational status is indicated by a green LED. Another valuable tool to facilitate commissioning is the innovative lock-in connector system Ultra-Lock™. Quick-connection technology from Woodhead, known for its reliability and ergonomical design, ensures contacting which is both fast and reliable due to its snap-in system even in the tightest of mounting situations. Instead of screw fastening and turning, a short plug-in or pull-out action is sufficient. The radial seal principle used eliminates the possibility of faults due to insufficient or excessive tightening. Also contributing to an easy commissioning process are special mounting systems, designed to permit mounting on round rods of the kind typically found along conveyor systems. These permit the models from all three series to be ideally height adjusted and set to any optional angle. A single screw is all that is required for fixture, and the sensor is ready to go. Another technological highlight implemented by Leuze in different models of the new series is reliable detection of stretch or shrink wrapped objects. Packaging using certain types of plastic coatings can act in the same way as a reflector. In cases such as these, a special lens prevents spurious switching processes which could result in costly production downtime.

Three series using different reflex and scanning principles

The smallest series of the new sensor generation is the 3B. With housing dimensions of just 32 x 11 x 17 millimetres, it is the world’s smallest retro-reflective photoelectric sensor which is also available as a laser photoelectric sensor using the autocollimation principle. It is capable of detecting miniature components from just 0.1 millimetres in size. Additional reflection principles are also available. The model spectrum is rounded off by a version for standard applications, a sensor using the autocollimation principle and a sensor for the detection of transparent media. The new diffuse reflection light scanners of the 3B series using red light LED as a light source are available in three different versions.

For standard applications with a scanning range limit of up to 400 millimetres, they offer extremely good black-and-white behaviour and reliable switching operation almost irrespective of the object and background properties. In the XL version, a broad rectangular light spot (3 x 40 mm2 at a distance of 50 mm) permits reliable detection of objects with gaps, boreholes and grooves, for instance when scanning pcb panels in productronics applications, transparent films or bottles, or grid-type structures of the kind encountered in blister packs and objects with changeable positions. Optimized for the detection of small components and structured coloured or shiny objects in front of a background at close range, the S version has a light spot diameter of just 4 millimetres at a distance of 100 millimetres.

The next biggest variant, the BR 25B, comes with a variety of different reflection principles. The standard version guarantees extreme performance reserves at ranges of up to 10 metres. The sensor for detection of stretch or shrink wrapped objects is configured for a range of 8 metres. A laser version guarantees optimum alignment convenience for ranges of up to 15 metres. An optional sensitivity setting creates maximum flexibility in a model size used as a preferred option in container conveyor systems or packaging lines.

The big BR 46B model using the reflection principle comes in a so-called power pack version for ranges up to 18 metres. These sensors offer functional reliability even when used with small or maladjusted reflectors or if heavily soiled, and are ideally suited for applications such as gap monitoring in high-bay warehouses. Optimized for use on roller conveyors, here too optimum functional reliability is achieved for the detection of stretch or shrink wrapped objects. There are different diffuse reflection light scanner variants on offer also in the biggest of these three series. The power pack with infrared LED has a range limit of 0 to 2500 millimetres and is ideally suited for the detection of shiny and dark objects. The HRTR 46B variant with extra-bright light spot permits simple adjustment and fast commissioning coupled with good detection characteristics. With a scanning range limit of 1200 millimetres, the laser scanner HRTL 46B permits highly precise positioning and reliable detection of small components. The HRTR 46B small beam with red light LED is designed specifically for the reliable detection of coloured structured objects of the kind occurring in packaging applications and in the woodworking industry. With its small light spot, it covers working distances occurring typically between 100 and 300 metres. Permanently set variants are also offered to complete the product range. With an operational scanning range of around 600 millimetres, these save the need for setting work and are ideally configured for conveyor system applications.

In summary

By redesigning these standard product series, Leuze has succeeded in coming up with a product spectrum offering enormous performance versatility practically from a single “mould”. The unique technologies used, some of them patented, offer outstanding performance and a significant reduction of costs over the entire life cycle. Further enhanced performance reserves, spurious and ambient light suppression, the special lens for reliable detection of stretch and shrink wrapped containers, as well as extreme seal tightness even under intensive cleaning conditions all combine to ensure maximum functional reliability in operation. Alongside a range of intelligent accessories such as the mounting system, technical features such as “brightVision®” and Ultra-Lock™ provide the guarantee of convenient handling and fast, simple commissioning.

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