| 摘要 |
<p>Method and device for monitoring of a moving web, such as a wire (10) in a paper machine, a felt, or a material web (W), such as a board or paper web. A radiation bar (L) is directed at the face of the web (10;W) to be monitored by means of a series of transmitters (201...20N), which radiation bar is transverse to the direction of movement (v) of the web (10;W). Radiation reflected from the web (10;W) and from the background is detected by means of a series of receivers (301...30M). The measurement signals obtained in this way are passed to an electronic unit (40), in which a quantity that characterizes the monitoring of the web is detected from said measurement signals. The approximate location of the edge (10a), the edges (10a,10b), or of corresponding discontinuities of the web (10;W) to be monitored is detected "digitally" on the basis of the radiation beam (Ln) of the radiation transmitter (20n) in whose area the greatest change takes place in the received radiation. The precise location of the edge or equivalent of the web (10;W) to be monitored is determined analogously by, with one another, comparing the amplitudes of the signals of the adjacent receivers (30n-1,30n) placed closest to the last-mentioned radiation transmitter (20n). <IMAGE></p> |
