Case story: Measuring roll

The actual feedback value of the effective speed of the metal strip is needed to control the roll stand drives. It is possible to measure this value using suitable sensors sited at the drive measuring roll between the stands. Due to the shock and vibration loads as well as aggressive cooling emulsions, the environmental conditions in which the devices are to be used can only be described as extreme. In addition, because the installation space is restricted the sensors also need to be adapted. Due to the loads mentioned above a measuring system installed to date was unable to supply interference-free speed signals.

Following discussions with the end customer Johannes Huebner Giessen installed a suitable measuring system with a magnetic encoder adapted to suit the conditions. The chosen MAG 260 comprises a pulse wheel with an external diameter of 260 mm as well as a scanning head with fully encapsulated electronics and protection class IP 67. The bearing-free system is not only shock and vibration proof, it also supplies interference-free signals even in the face of extreme conditions resulting from aggressive fluids and vapours. Doing without a separate marker channel made it possible to implement the extremely slim design width of just 10 mm as specified.