DCSs (distributed control systems) consisting of many devices and an open network are used in factory automation and building automation areas. Before making the actual DCS, we must accurately estimate the control characteristics of network in the DCS. In this paper, we propose two object-oriented design patterns which specify the structure and behavior of the communication protocol of devices, and synchronize the clocks of components in the DCS model. Finally, we evaluate the correlation between the result of DCS simulation using the CAN protocol model and the network communication of the actual CAN-based DCS.