OMSimulator is an FMI-based co-simulation tool and recent addition to the OpenModelica tool suite. It supports large-scale simulation and virtual prototyping using models from multiple sources utilizing the FMI standard. It is integrated into OpenModelica but also available stand-alone, i.e., without dependencies to Modelicaspecific models or technology. OMSimulator provides an industrial-strength open-source FMI-based modelling and simulation tool. Input/output ports of FMUs can be connected, ports can be grouped to buses, FMUs can be parameterized and composed, and composite models can be exported according to the (preliminary) SSP (System Structure and Parameterization) standard. Efficient FMIbased simulation is provided for both model-exchange and co-simulation. TLM-based tool connection is provided for a range of applications, e.g., Adams, Simulink, Beast, Dymola, and OpenModelica. Moreover, optional TLM (Transmission Line Modelling) domain-specific connectors are also supported, providing additional numerical stability to co-simulation. An external API is available for use from other tools and scripting languages such as Python and Lua. The paper gives an overview of the tool functionality, compares with related work, and presents experience from industrial usage.

The ease of use and the high abstraction level of equation-based object-oriented (EOO) languages such as Modelica has the drawback that performance problems and modeling errors are often hard to nd.To address this problem, we have earlier developed advanced performance analysis and equation model debugging support in the OpenModelica tool. The aim of the work reported in this paper is to perform an independent investigation and evaluation of this equation model performance analysis and debugging methods and tool support on industrial models.The results turned out to be mainly positive. The integrated debugger and performance analyzer locates several kinds of errors such as division by zero, chattering, etc., and greatly facilitates nding the equations that take most of the execution time during simulation.It remains to further evaluate the performance proler and debugger on even larger industrial models.