SYSTEM AND METHOD FOR CONTROLLING A VALVE

摘要

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 (204,206) are arranged in a high-availability configuration and individually coupled to a controller (216). A first positioner (204) includes an output coupled to a switch (218) and a second positioner (206) includes an output coupled to the switch (218). The operating state of the first positioner (204) is monitored and the output of the first or second positioner (204,206) allowed to pass through the switch (218) to the control valve (214) is dependent upon the operating status of the first positioner (204).