This units is used when you want to control the valve opening. Put over the image and drag your unit to the main screenwork, using button right of your mouse. The instruments only appear when you click over the instrument in the main menu.
This is list of all instruments units that you can use.
FIC. Choose this instrument unit when you want to control the valve opening by flowrate in the pipe.
When you drag this unit to the main screenwork, that appear.
Set the point, that you want you use in the internal program.
In order to control the valve opening you need to drag a instrument for control this unit, and put over the valve.