A system and method for controlling a valve increases the availability of a control valve assembly used in a control process. A pair of positioners are arranged in a high-availability configuration and individually coupled to a controller. A first positioner includes an output coupled to a switch and a second positioner includes an output coupled to the switch. The operating state of the first positioner is monitored and the output of the first or second positioner allowed to pass through the switch to the control valve is dependent upon the operating status of the first positioner.
