Internal Fields

This screen allows you to add formulas for the internal fields Duration and Rate to be used by those tasks where the type has specifically been set to Calculated Duration or Calculated Rate (as opposed to Fixed Duration, Fixed Rate, Cyclical or Hammock). This is useful if a task's production rate depends on e.g. rock hardness, type of drilling etc.

This screen contains 2 grids that allow you to set up formulas similar to how you would set up formulas for production fields.

In order for these formulae to have any effect on a task's duration or rate, the relevant task needs to have its type set to Calculated Duration or Calculated Rate. This can be done in the Task Information form that is displayed when double-clicking on a task, or in the Task Type column when this is displayed in the task table. Such a task will display an icon in the Indicator column to show that it's duration or rate is calculated, for example:

You use this tab to specify the formulas required to calculate the value of the Production Field.

Field Description
Apply to Tasks Specifies the tasks (filter) to which this formula will apply.
Formula Specifies the formula to be applied to calculate the rate or duration.

Click in the Formula field. The  displays. Click . the Formula Builder screen displays. Enter the values, as required.
Driving Property This only applies when calculating the rate. It is the property upon which the rate is based.

Example: if your are calculating the rate, and the formula returns a numeric value of 20, then this is the property that gets added to the numeric value, e.g. 20m (20 metres). The time unit naturally still needs to be appended to this as explained in the following row.
per time unit This specifies the time unit that will be applied to the result of the formula.

Example: if your are calculating the duration, and the formula returns a numeric value of 10, then this is the time unit that gets added to the numeric value, e.g. 10d
Filter Details Clicking on this cell allows you to view the details of the currently selected filter in the Apply to Tasks column, instead of having to navigate to the task filter screen.