Abstract: To reach an originally set web position again with a web movement control device following a tear in the web and renewed drawing-in of a web of material, sensors which can be adjusted independently of one another and coupled such that two sensors move synchronously in opposite directions are provided. During an edge search, the two sensors can be adjusted separately and independently of one another and moved synchronously in opposite directions for centre control after a tear in the web for repositioning the sensors.

Abstract: A method for positioning a sensor for a web movement control device, in which the sensor executes an edge search process, in order to achieve a rapid and exact positioning of sensors by specifying a relatively early stop threshold for the sensor movement, after-running of the sensor is detected in that after the after-running position is detected by the sensor signal the difference between the preset stop value and the stop value actually reached is formed and specified as the new stop value, after which the edge search process is repeated with the corrected stop value.

Abstract: A method of adjusting the working point of a web movement control device beyond the measuring range of the sensor is disclosed.

Abstract: In a web movement control device with a sensor which detects the edge of a moving web of material in a contact-free manner and can be adjusted by a sensor adjustment device, to compensate for a change of material to be controlled and/or a soiling of sensors, the sensor adjustment device is driven by an electronic signal processing device to adjust movement transversely with respect to the edge of the web. The signal processing device monitors the sensor signal changes which occur and derives a bright value or a dark value from the absence of a signal change during the movement adjustment stores the value. An intermediate value is calculated from the stored value as a control value for web movement control and stored. Under given operating conditions, this program cycle is repeated.