Abstract: The invention relates to a method for controlling a hydraulically actuated drive unit (1-3), especially for a valve or control device, wherein at least on a part of the displacement of the drive unit the displacement speed (v?) is detected and compared with a predetermined target displacement speed (v), whereupon in the case of a difference between actual value (v?) and target value (v) of the speed, the controlling of the drive unit (1-3) is changed such that the displacement speed (v?) of the drive unit is adapted to the target value (v).

Abstract: The invention relates to a method for indicating the position of a hydraulically actuated armature, having a piston (1.21) in a cylinder (1.2) for actuating the armature (1.1), which cylinder is connected by means of two hydraulic lines (2, 3) to a switch valve (7) through which the hydraulic lines can be switched between pressure-conducting feed flow and pressureless return flow, wherein the flow of the hydraulic fluid flowing through one of the hydraulic lines is converted into a number of electric pulses, each of which corresponds to a pre-determined unit of volume of the hydraulic fluid, the switch valve (7) is connected to supply lines (P, T), to which further switch valves (7) are connected for actuating further armatures (1.

Abstract: The invention relates to a method for indicating the position of a hydraulically actuated armature, having a piston (1.21) in a cylinder (1.2) for actuating the armature (1.1), which cylinder is connected by means of two hydraulic lines (2, 3) to a switch valve (7) through which the hydraulic lines can be switched between pressure-conducting feed flow and pressureless return flow, wherein the flow of the hydraulic fluid flowing through one of the hydraulic lines is converted into a number of electric pulses, each of which corresponds to a pre-determined unit of volume of the hydraulic fluid, the switch valve (7) is connected to supply lines (P, T), to which further switch valves (7) are connected for actuating further armatures (1.