PURPOSE: To detect highly accurately the elongation percentage of a steel sheet in all regions of rolling speed by using a pulse generator having a comparatively low resolving power by setting a preset value corresponding to a rolling speed to a pulse counter at the inlet side in the method of detecting the elongation in the longitudinal direction of steel sheet in a cold temper mill.
CONSTITUTION: A mill speed (a speed of steel sheet) is detected by a mill speed detector 11 to compare the speed with V1WVn respectively by using speed comparators 121.2.n. Any one of corresponding comparison circuits is actuated to select preset values P1WPn by using gate circuits 131.2.n. The value Pn is preset to a preset counter 15 connected to a pulse generator 7 of the inlet side through an OR circuit 14. A counter 16 starts to count by a signal B at the timing of said presetting. Further, when the mill speed is V1, and the P1 is set to the counter 15; the value Pe=P1, where Pe is an output of the counter 15 is outputted to an elongation computing-circuit 17. On the other hand, the counter 16 stops to count by a signal A and outputs a count value P4 obtained at that time. The above mentioned procedure is repeated in order in accordance with the mill speed.
OBANA MASANOBU
HITOMI NOBUYUKI
HITACHI LTD
HITACHI ENG CO LTD