The Function 
Profiles Link command in the expression editor inserts the token l_fcv(<parameter>) at the insertion point in the editing pane. This token defines a link relationship between two parameters. Replace the dummy
<parameter> argument with a parameter name.
l_fcv(sphere.kine.local.posx)
Links the value of the target parameter to the local X position of a sphere according to a function curve. Use Set Relative Values to set keys on the function curve.
In addition to the l_fcv command, you can also enter these commands for multi-linked and orientation-linked parameters (they are not available from the Function menu).
l_interp(<param1> <param2> ...) - command for multi-linked parameters defines a link relationship for the combination of animation values from many parameters driving one.
l_interpOri((rotx, roty, rotz)<param>) - command for orientation-linked parameters defines a link relationship for an object's orientation driving a parameter.
These expressions are created when you use the Link with Multi command in the Parameter Connection Editor or on the Animation menu, and Link with Orientation command on the Animation menu (see The Parameter Connection Editor [ Animation ]).
l_interp(sphere.kine.local.posx, sphere.kine.local.posy)
Links the value of the target parameter to the combined local X and Y positions of a sphere. Use Set Relative Values to create values used by the Interpolator. Then open the parameter's Expression operator to edit the Falloff value on the Interpolator page (see Editing the Falloff [ Animation ]).
l_interpOri(cube.kine.local.rotx, cube.kine.local.roty, cube.kine.local.rotz)
Links the value of the target parameter to the complete local orientation of a cube that is calculated in quaternion space. When you change the orientation of the cube, the linked parameter changes as well. Use Set Relative Values to create values used by the Interpolator. Then open the parameter's Expression operator to edit the Falloff value on the Interpolator page (see Editing the Falloff [ Animation ]).
