Disclosed herein, amongst other things, is a control structure for a molding system (900). The control structure includes a controller (106, 934) and a valve actuator (104) for positioning a valve member (102) of a valve (101) for regulating flow of molding material in the molding system (900), wherein the controller (106, 934) is configured to monitor an operating parameter of the valve actuator (104) for indirectly appreciating an indication of a molding parameter of the molding system (900).