An injection molding machine uses a native controller and a retrofit controller to effectively control its operation. The controllers may determine and/or receive information regarding the machine's maximum load capacity, and may also determine a current operational load value of the machine. The retrofit controller may cause the machine to operate at any number of combinations of settings of operational parameters which result in the machine operating at or below the maximum load value by adjusting any number of machine parameters associated with the injection molding machine based on feedback sensors measuring real-time operating conditions of the machine.