The history chart shows values of the machine as a diagram.
By clicking the plus-button on the left, B formula can be added. On the bottom of this view a window appears, where you can enter the formula, or you edit it with a double click in the line. By clicking the minus-button you can delete the chosen formula.
The values of these formulas are shown in the history chart on the y-axis, while the x-axis describes the corresponding step in the trace.
If needed, the charts can be displayed with rectangular curves or als separate charts. Via "Start at position:" you can choose a step in the trace as a starting pint of the chart.