Test & measurement


In automotive quality inspections, verifying the presence of dark parts against an equally dark background is extremely common. In addition, a wide variety of target colours can be present in this application.


Dark anD VarieD TargeTs


Dark objects are already difficult for many sensors to detect. Because they absorb red light, dark objects significantly reduce the amount of light that returns to the sensor. In addition, very dark targets against an equally dark background are even more challenging for many sensors, especially those that rely on colour or contrast, to reliably detect. Many car seats consist of black fabric or leather material with black plastic components, such as levers and buttons to adjust seat height and tilt. Verifying the presence of these components is essential to ensuring the quality of the final product. In addition to dark components on a


dark background, the variety of vehicle trims automotive manufacturers produce means that seats and seat components come in a wide range of colours, including black, gray, tan, and even fabrics with multiple colour transitions such as plaid. It is therefore important to identify a solution that can reliably detect all possible colour combinations.


Laser DisTance sensors wiTh high excess gain


A triangulation-based laser sensor like the Q5X sensor has no difficulty detecting dark targets on dark backgrounds when there is a height difference. In addition, a high excess gain will enable the sensor to reliably detect even the darkest objects even against a dark target. The Q5X sensor can reliably detect these


automotive seat inspection


challenging targets even out to 2m and at an angle, enabling greater mounting flexibility. In addition, the Q5X can detect targets of all colours, including multicoloured objects, with ease. This ensures all varieties of automotive seats can be reliably inspected with one device. The Q5X sensor solves the most difficult


distance-based applications, even at acute angles. The Q5X reliably detects extremely dark targets (< six per cent reflective), black targets against a black background, black targets against a shiny metal background, clear and reflective objects,


multicolour packaging, and targets of all colours. The Q5X features a durable, cost-effective


plastic housing, and an extensive offering of metal protective brackets for the most difficult industrial environments. With an intuitive user interface, the Q5X sensor is simple to deploy quickly, saving time and costs. In addition, dual teach mode enables the sensor to verify multiple conditions - such as part presence and orientation - with a single device. This reduces sensor inventory requirements, as well as installation and maintenance costs.


Reflective items, such as drink cans, can create false sensing. The Q20 is designed to detect only the light returned from the reflector, differentiating between reflector and can. Detecting the presence of shiny or


reflective objects is a challenge in many applications where a retroreflective sensor would normally be the ideal solution due to space, cost, convenience or other considerations. In retroreflective sensing, the sensor is


looking for its emitted light returned by the retroreflector. Shiny objects can act as reflectors themselves, returning enough light to the sensor to cause unreliable sensing. A solution is needed that will only see the light returned from the retroreflector, and not light returned from shiny targets.


Instrumentation Monthly October 2019


Detecting shiny, unfinisheD cans WORLD-BEAM Q20 polarised


retroreflective mode sensors use polarising filters to detect only the light returned from the retroreflector, ignoring light returned from shiny objects. Natural light is made up of waves having a variety of polarisations. Photoelectric sensors with polarizing filters emit and detect only light waves of a specific polarisation while rejecting unwanted light of other polarisations. In this application, the sensor is designed to see only the light returned from the retroreflector. When the unfinished cans pass between the sensor and the retroreflector, the light reflected off the cans has a different polarisation than the light returned by the retroreflector. As a result, the beam will be blocked by the cans and the output will be triggered.


Continued on page 34... 55


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82