Abstract: Foreign matter is removed from a digital hydraulic pressure controller having two portions connectable to each other and each including two valve arrays with a plurality of individually switchable valve means having different flow cross-sections and connected in parallel within a valve array. One valve array of each pressure controller portion can connect a supply line to a controller output line and the other valve array can connect the output line to a drain line. The two pressure controller portions are connected, the valve means having the largest flow cross-section of the valve array of the one portion on the supply line side is opened, the valve means having the largest flow cross-section of the valve array of the other portion on the drain line side is opened and the opened flow path is flushed through the pressure controller with pressurized working fluid, while the other valve means are closed.

Abstract: A digital hydraulic controller has a feed line, a drain line, an output line and a plurality of individually switchable on/off valves which selectively connect the feed line to the output line or which connect the output line to the drain line. A controlled quantity is detected which includes a pressure and/or a flow rate of a fluid in the output line. One of the valves is selected to be switched to control the amount and direction of fluid passing through the valve for controlling the controlled quantity to approach a target value. A test sequence is performed including calibration of the individual valves by alternately opening two of the valves, one of which connects the feed line to the output line and the other connects the output line to the drain line, and by calculating and setting calibration values for the individual valves.

Abstract: A digital hydraulic controller has a feed line, a drain line, an output line and a plurality of individually switchable on/off valves which selectively connect the feed line to the output line or which connect the output line to the drain line. A controlled quantity is detected which includes a pressure and/or a flow rate of a fluid in the output line. One of the valves is selected to be switched to control the amount and direction of fluid passing through the valve for controlling the controlled quantity to approach a target value. A test sequence is performed including calibration of the individual valves by alternately opening two of the valves, one of which connects the feed line to the output line and the other connects the output line to the drain line, and by calculating and setting calibration values for the individual valves.

Abstract: A digital hydraulic controller has at least two rows of valve elements: one can connect a supply line to a controller output, the other can connect the controller output to an outlet line. The valve elements of each row are connected in parallel and are switchable individually or simultaneously in different combinations with each other and have different flow cross sections. The valve element with the smallest flow cross section is present twice in the row. A system unit has a differential cylinder and a digital hydraulic controller with four rows of valve elements, two of which are, with their common controller output, connected to the one pressure chamber of the differential cylinder, while the other two rows of valve elements are, with their common controller output, connected to the other pressure chamber of the differential cylinder. The differential cylinder can be used as a precisely adjustable linear actuator.

Abstract: Foreign matter is removed from a digital hydraulic pressure controller having two portions connectable to each other and each including two valve arrays with a plurality of individually switchable valve means having different flow cross-sections and connected in parallel within a valve array. One valve array of each pressure controller portion can connect a supply line to a controller output line and the other valve array can connect the output line to a drain line. The two pressure controller portions are connected, the valve means having the largest flow cross-section of the valve array of the one portion on the supply line side is opened, the valve means o having the largest flow cross-section of the valve array of the other portion on the drain line side is opened and the opened flow path is flushed through the pressure controller with pressurized working fluid, while the other valve means are closed.