For this project, we studied modeling, simulation, control and fault diagnosis of a hybrid system using a three tank testbed. To facilitate our project, we developed software for interfacing the laboratory testbed with other software components. The system was modeled using hybrid bond graphs and the model was implemented using Matlab/Simulink. To validate the model, we compared the simulated output to the testbed’s behavior using several control sequences and computed the average absolute error for each. With the validated model, we then implemented a set-point controller for the testbed using a limited-lookahead approach. The controller’s behavior was verified first on the simulation and then on the testbed. Finally, we integrated the testbed with the Fault Adaptive Control Technology (FACT) software, developed at the Institute for Software Integrated Systems (Vanderbilt University), to detect and identify faults in the system. The results show that the model-based controller effectively maintains the system state around the set points, and the FACT Diagnoser can be used to successfully detect and identify different failure modes of the testbed.