Three typical types of control used by facilities that handle webs and steel plates are edge position control, tension control, and register control. Edge position control systems prevent products from deviating from their proper path as they travel, and ensure that the edges of rolls of webs are uniform. Edge position control systems control the edge or center position of a web when it is being unwound from a roll into the processing machine and during rewinding. Edge position control is the most important technology and has the longest history in the web control. The root of edge position control system has been the jet-pipe hydraulic control system., but now many technologies are applied for the recent control systems. The new image sensing technology will be applied to the web control.
