| 摘要 |
PURPOSE:To perform measurement accurately even at a low speed without lengthening a sample time by modifying a pulse repetition frequency which is supplied to first and second counters based on the feeding speed of a material. CONSTITUTION:Pulse trains from an input side pulse generator 1 and an output side pulse generator 2 are inputted to first and second pulse amplifiers 9 and 10 in a pulse repetition frequency modifying means 12. the pulses are transformed into the pulses having the numbers of pulses of one time, twice, and four times. A speed counter 5 and a comparator 11 judge whether the feeding speed of the material is 1/2 or 1/4 the maximum or not, and change the multiplication factor of the pulses to twice or four times. The counted values of the counters 3 and 4 employing said pulses are subtracted 7 and divided by the value of the counter 4 in a divider 8, and the extension ratio is computed. In this constitution, even though the feeding speed of the material is reduced, the measurement can be performed with the same accuracy and in the same sampling time as at the maximum speed. |
