This paper proposes a new software composition method for automated machines that exploits their mechatronic modularity. It is demonstrated that desired behavior of a certain class of machines can be composed of behaviors of its mechatronic components, including fully decentralized scheduling and operation control. This aims at increased performance of software design and maintenance, as well as systems' flexibility and reconfigurability. The IEC 61499 Function Blocks' (FBs) architecture is used as an implementation platform that enables system-level simulation and transparency of deployment. A configurable pick-and-place (PnP) manipulator with decentralized control synthesized using the proposed approach is chosen as an illustrative example.