In O-Calc there are a number of options available to customize the tension on a span. These options can be found by selecting a span, and selecting the Tension Sag filter in the Data Entry Window.

When Table is selected, a Tension Table can be created by selecting the light blue dot to the right of the word “Tension”. That will open the Span Tension vs Length window.

Under the Value dropdown, span lengths can be added or removed. The tension at a given span length is linearly interpolated using the table.

When the desired span lengths are added, the tension at each length can be set.

Table must be saved under the File>>Save option before closing this window.