The WirelessHART protocol is one of the most promising standards for wireless communication in industrial automation plant systems. Control processes and the communication between them must be scheduled appropriately, such that the I/O data is correlated. In large networks, selecting a suitable schedule is a long and error prone exercise. This research report illustrates the design and realization of a WirelessHART system development tool, meant to support the design decisions in communication and processing scheduling. A simulator of such a system is built, to preview the resulting system performance. The purpose of designing the simulator is to support a more efficient usage of the timing specifications, and to offer collision free communication between network devices. The tool allows the development of the system starting from control loop levels, and provides information of possible errors in dataflow dependencies and network access conflicts.