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.