The actual feedback value indicating the speed of the metal strip is required to effectively regulate the roll stand drives. It is possible to measure this value using suitable sensors located at the drive measuring roller between the stands. Shock and vibration loads as well as aggressive cooling emulsions mean the devices need to withstand extreme environmental conditions. In addition, the sensors also need to be adapted due to restricted installation space. The loads mentioned above meant an existing measuring system installed to date was unable to supply interference-free signals speed signals.
Measuring roll in roll stand
Following discussions with the end customer Johannes Hübner Giessen installed a suitable measuring system with magnetic sensor technology that could be adapted to suit the conditions. The selected MAG 260 consists of a pulse wheel with an outside diameter of 260 mm as well as a scanning head with completely encapsulated electronics sealed to IP67. The bearing-free system is impervious to shock and vibration; it supplies interference-free signals even when subjected to aggressive liquids and vapours in extreme environments. By doing without a separate reference channel it was possible to implement the extremely slim 10 mm design width as specified.