Mechatronic Systems are characterised by interacting subsystems of different types. To model this class of dynamic systems an interdisciplinary approach is required. In this paper a way to model a controlled hydromechanical system using three different kinds of simulation tools is presented. The mechanical system, described in MOBILE, is coupled with a DSHplus model of the hydraulic system and a controller modelled in MATLAB/SIMULINK. This concept is applied to the oscillating boom of a concrete pump.