CONTROL DEVICE FOR FLOW RATE CONTROL VALVE

摘要

The neutral position of a control device for a flow rate control valve is accurately learned by means of a simple configuration. The control device for a flow rate control valve is provided with an actuator (12); an operation fluid supply source (11); a stroke sensor (14); a flow rate control valve (15) which comprises a valve element (19) and is provided with a supply unit (17a) communicating with the operation fluid supply source (11), a discharge unit (18a) discharging operation fluid, and a communication unit (16a) communicating with the actuator (12); and a control unit (20) which controls the valve element (19) according to values detected by the stroke sensor (14). The control unit (20) comprises a neutral position learning unit (22) wherein the movement amount of the valve element (19) that corresponds to the neutral position thereof is leaned from the movement amount of the valve element (19) at the time when it is determined from a value detected by the stroke sensor (14) that the valve element (19) is in the neutral position whereat the communication unit (16a) is blocked after the valve element (19) moves from the location of the discharge unit (18a), and from the movement amount of the valve element (19) at the time when it is determined that the valve element (19) is in the neutral position whereat the communication unit (16a) is blocked after the valve element (19) moves from the location of the supply unit (17a).