am block does not copy the state of its av input to the out output, except once immediately after the module is loaded. If the value of the av input is needed elsewhere in the application, it has to be connected to the point of use and the out output is not used.

out-output is intended for connecting the operated value coming from the user interface to the FbCAD application. If the change in the operated value is to be displayed in the user interface, the out output is connected to the av input.