| 摘要 |
A method and an apparatus provided to calculate and control the elongation in a running web (16), e.g. in connection with a preparation of a web in a printing machine. In connection with at least an increase or decrease in the web tension, the length change in a reference length of the web material is measured, and by means of web tension meters the web tension before and after the web tension change ( sigma 1- sigma 2) or each one of the web tension alterations is determined. The tension-free length (no) of the reference length is also calculated and if it is needed, the elongation of the web is corrected through an increase or a decrease in the web tension depending on said measurements. |
