The paper deals with modelling and control problem of machining centres. In particular, here only the pallet transportation system is analysed. The aim is to provide formal design models for the control engineer, so as to help the reconfigurability and diagnosis of specialised, software-intensive automation systems, and to exploit the potentials of agent-based control software development. The formalism of Modular Finite State Machines (MFSM's), well-known from the scientific literature in the manufacturing control field, is here adopted to represent the formal behaviour of control modules of the pallet transportation system in machining centres.