Abstract: A control arrangement for use in a hydraulic control system including a control valve having at least two movable elements, such as spools or poppets, that is adapted to control a main flow through the control valve. The control arrangement further includes a control unit. In an embodiment the control arrangement is adapted to control the operation of the control valve in accordance with a first control scheme, monitor an operating parameter of the control system, and control the operation of the control valve in accordance with a second control scheme in the event that the value of the operating parameter falls outside of a predetermined range.

Abstract: A control arrangement for use in a hydraulic control system including a control valve having at least two movable elements. The control arrangement is configured to control the positions of the two movable elements such that fluid from a common fluid pressure source is applied to both of the control surfaces of an actuator to drive the actuator. In an embodiment, the control surfaces have different effective areas.

Abstract: A control arrangement for use in a hydraulic control system including a control valve having at least two movable elements, such as spools or poppets, that is adapted to control a main flow through the control valve. The control arrangement further includes a control unit. In an embodiment the control arrangement is adapted to control the operation of the control valve in accordance with a first control scheme, monitor an operating parameter of the control system, and control the operation of the control valve in accordance with a second control scheme in the event that the value of the operating parameter falls outside of a predetermined range.

Abstract: A method for resetting a calibration of a sensor operating out-of-range in a hydraulic actuation system is provided. The hydraulic actuation system includes a pump, a reservoir, a plurality of work-ports, a plurality of sensors, and a valve system, and a controller for regulating the hydraulic actuation system based on fluid flow demand and sensed pressures. The method includes detecting the sensor operating out-of-range, opening all work-ports to the reservoir, resetting all sensors to reservoir pressure, supplying all sensors with fluid at maximum pump pressure, and sensing the maximum pump pressure at each sensor. Additionally, the method includes determining an average pressure value across all sensors, assigning the determined average pressure value to the sensor that is operating out-of-range, and resetting the calibration of the sensor that is operating out-of-range based on the reservoir pressure and the average pressure values.

Abstract: A method for resetting a calibration of a sensor operating out-of-range in a hydraulic actuation system is provided. The hydraulic actuation system includes a pump, a reservoir, a plurality of work-ports, a plurality of sensors, and a valve system, and a controller for regulating the hydraulic actuation system based on fluid flow demand and sensed pressures. The method includes detecting the sensor operating out-of-range, opening all work-ports to the reservoir, resetting all sensors to reservoir pressure, supplying all sensors with fluid at maximum pump pressure, and sensing the maximum pump pressure at each sensor. Additionally, the method includes determining an average pressure value across all sensors, assigning the determined average pressure value to the sensor that is operating out-of-range, and resetting the calibration of the sensor that is operating out-of-range based on the reservoir pressure and the average pressure values.