The present invention relates to a method for operation of an electro-magnet (2, 3) connected to an intrinsically safe direct current circuit which can be switched under control between two positions for the operation of the closing body of a hydraulic valve (5, 6), whereby using of an electronic control unit, the coil windings of the electro-magnet (2, 3) are taken in the pull-in phase of the armature of the electro-magnet to an exciting current and in the retaining phase of the armature to a lower retaining current as opposed to the excitating current, and a device with which the retaining current reduction is realized.