A dynamic testing system includes a test station and at least one controller. The test station includes a hydraulic actuator configured to drive an actuation of a test subject using a hydraulic fluid flow, and a control valve that includes a housing, a valve body contained within the housing having a position that controls a flow rate and direction of the hydraulic fluid flow, a valve body driver configured to adjust the position of the valve body based on a reference signal, and a valve position sensor configured to output a position signal that is indicative of the position of the valve body. The at least one controller is configured to obtain a current position of the valve body using the position signal, obtain a diagnostic reference, detect a diagnostic condition based on a difference between the current position and the diagnostic reference, and generate a diagnostic signal.

A compressed-air system having a safety function and a method for operating such a compressed-air system. The compressed-air system contains two working valves, which each can selectively assume an aerating position that aerates a load and a venting position that vents the load. Both working valves are redundantly connected on the output side to the load by means of a separating device. The separating device allows one or the other of the working valves to be separated, while the aeration of the load is maintained, in order to subject the one or the other working valve to an examination of the switching function of the one or the other working valve.

A method of calibrating an electrohydraulic valve is disclosed. The method includes actuating an on-off valve to an open position. A speed of a fixed displacement pump is regulated to establish a desired flow rate at an outlet of the pump. The pump is in fluid communication within a closed loop circuit with the on-off valve and the electrohydraulic valve. A target pressure in the closed loop circuit is determined as a function of the desired flow rate. The method further includes increasing a current to the electrohydraulic valve and monitoring the target pressure in the closed loop circuit. A start of a fluid flow through the electrohydraulic valve is determined based on a drop in the target pressure within the closed loop circuit.

A system for determining an estimated output from a variable displacement hydraulic pump includes a prime mover, a torque sensor, a pressure sensor, and a displacement sensor. A controller is configured to determine the output torque from the prime mover, determine an input torque to the variable displacement hydraulic pump based upon the output torque, determine an output from one of the pressure sensor and the displacement sensor based upon the signals. The controller is further configured to determine a failure of another of the pressure sensor and the displacement sensor and determine an estimated output from the another of the pressure sensor and the displacement sensor based upon the input torque to the variable displacement hydraulic pump and the output from the one of the pressure sensor and the displacement sensor.

A control system for a pressure relief valve can include a controller and an actuator. The controller can control the actuator to at least partially open a main valve of the pressure relief valve and can determine one or more operational characteristics of the pressure relief valve based on a response of the valve to the controlled movement of the actuator.