This article deals with the control of variable displacement units connected to a constant pressure net. In particular the dynamical behaviour of two coupled secondary units in a speed- and torque control circuit is described and the decoupling of the two motors by the control technique is demonstrated. On this occasion results the possibility of recovering the energy into the hydraulic net. This onstellation is among other applications of special interest for power transmissions or testing benches, in case tension is applied to a traction mechanism or tape.