Special designs and variants of proximity sensors

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: the receiver with an adjustable critical value. The threshold corresponds to a specific grey-scale value on the object. If the threshold of the grey-scale value is fallen below of or exceeded, the printing mark sensor changes its switching status. Depending on the different types of application (varying reflection with different colour contrasts), printing mark sensors are often equipped with optical sensors whose wavelengths can be changed by using different light emitting diodes. Even bulbs in conjunction with selectable colour filters are used. Printing mark sensors can be used with fibre optic adaptors. However, in such cases, luminous radiation is as a rule unfocussed and the sensing width may vary; however contrast sensitivity quickly diminishes as the distance increases. Printing mark sensors are also able to detect very small marks. Designs incorporating an LED light source are for instance able to detect printing marks of a dimension of 0.5 mm at switching distances of 20 mm, whereas designs using laser radiation source are able to...
View Full Document

This note was uploaded on 11/01/2012 for the course CHEMICAL 102 taught by Professor Jamesrodriguez during the Spring '12 term at Universidad Politécnica de Cartagena.

Ask a homework question - tutors are online