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Emerald Group Publishing Limited
Copyright © 1999, MCB UP Limited
Distance sensors feature CCD technology
Distance sensors feature CCD technology
Keywords Distance, Sensors
Leuze electronic is one of the very first manufacturers to offer an optical distance sensor using CCD (charged coupled device) receiver lines (see Plate 2). This means there is now commercially available highly accurate sensors that will detect changes as small as 0.5mm and are unaffected by reflective properties of an object's surface.
Plate 2 New Leuze distance sensors feature CCD technology
Remote-operating measurement techniques are frequently called for, particularly where lightweight, deformable or fast-moving objects are involved. It is not long since a major breakthrough was achieved in this field with so-called PSD (position-sensitive detector) elements. Now, the optical metrology sector has made another quantum leap with a new type of distance sensor equipped with a CCD receiver line and a generous share of its own "intelligence" to open up a wide range of new possibilities.
There is nothing intrinsically new about CCD; however, up until a short while ago, it was only possible, for pricing reasons, to use this technology in relatively expensive products, for example video cameras or image recognition systems. In the meantime, however, efficient CCD lines at attractive prices have become available on the market and optosensory specialist Leuze electronic was quick to act and has developed its own CCD line sensor-model ODS 96.
The functional principle of the sensor is simple to understand. An LED light source acts as a transmitter operating with infrared light (880nm). The light reflected by the object hits the CCD receiver line, the position of the received light on the line depends on the distance of the measured object. The value is processed by an integral microprocessor to give either analogue outputs with 1 to 10V or 4 to 20mA signal or digital outputs for RS232 or RS485 interfaces. There is also a variant offering two switching outputs with teach-in facility for any optional distance within the measurement range. Also, the hysteresis can be parameterized, permitting functions such as monitoring of limiting values or two-point controls to be established.
A wide number of applications call for the detection of distances, from the many different types of positioning function through to content level control of bottles or other vessels. Typical applications include content measurement, stack positioning, contour determination and volume calculation, package sorting, board thickness measurement in the woodworking industry and many more.
The new ODS 96 sensor is designed for distances ranging from 100 to 600mm and supplies its distance information either in analogue form (1 to 10 V or 4 to 20mA) or as a serial 14 Bit wide data word. The distance sensor achieves a resolution of < 0.5mm and offers repeatability of ±1% of the measured distance. Design of the new sensor also gives effective filtration and internal signal processing, guaranteeing a high degree of resistance to extraneous light.
The distance sensor operates at direct voltages of between 10 and 30V (digital versions) or 10 and 30V (analogue versions). Hard-wearing metal housings and highly resistant lens cover made of hard glass combine to afford optimum protection under even the toughest environmental conditions. The requirements of protection class IP67 and all the relevant ECM regulations are complied with as standard.
The new ODS 96 sensor from Leuze Mayser has clear advantages over other products using the more conventional PSD elements and also using the triangulation principle. The benefits affect important aspects such as precision, insensitivity to temperature and evaluation flexibility.
For further information please contact John Longcroft, Leuze Mayser electronic Ltd, Alington Road, Eynesbury, St Neots, Cambs PE19 2RD. Tel: +44 (0)1480 408500; Fax: +44 (0)1480 403808.