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The demand for model exchange between development partners will grow during the next years. The Functional Mockup Interface (FMI) is a well received tool independent approach for model exchange. The Original Equipment Manufacturers (OEM) have committed themselves to support FMI as exchange format for simulation models. Therefore, the FMI is a promising candidate to become the industry standard for model exchange and crosscompany collaboration. In this paper, the FMI standard is evaluated from an industrial perspective.

The Functional Mock-up Interface (FMI) (Modelica Association 2021b) is a tool independent standard for the exchange of dynamic models and for co-simulation. FMI 2.0, released in 2014, is recognized as the de-facto standard in industry for exchanging models and tool coupling, and is currently supported by more than 160 simulation tools. Version 3.0 of the standard brings many new features that allow for advanced co-simulation algorithms and new use cases such as packaging and simulation of highly accurate virtual Electronic Control Units (vECUs). Besides Model-Exchange and Co-Simulation, a third interface type, Scheduled Execution, is defined for purely discrete, RTOS-like, simulation and supports preemption. Clocks allow the synchronization of events between Functional Mock-up Units (FMUs) and the importer. There is better support for data types including binary data and arrays. Advanced co-simulation approaches are enabled by intermediate variable access between communication points and allowing event handling. The composition of systems from FMUs is simplified by terminals that can bundle multiple signals. The concept of layered standards allows the extension of the FMI standard.

The Functional Mockup Interface (FMI) is more and more adopted by industrial users, increasing the pressure for higher quality and standard compliance of FMI supporting tools. The FMI cross check infrastructure was created to support tool vendors in their quest for quality improvements and to give users some measure of confidence in the tool quality. Currently it is up to the tool vendors which FMUs to submit there. For this reason the features tested in the FMI cross check are incomplete and interpretation of failures is difficult. While for FMI export there is the FMU compliance checker to test a wide variety of FMI features, no means are available today to prove standard compliance for FMI import. This will be overcome by adding reference FMUs to the FMI cross check, testing specific features of the FMI standard for standard compliance and giving detailed feedback, if an importing tool violates the standard. The paper describes the realization and the importance of reference FMUs.

This paper explores the possibility to include and execute source code functional mockup units on Bosch electronic control units. A prototypical realization is presented, and assumptions as well as limitations are documented. Special emphasis is laid on requirements for the contained C-code. Furthermore, aspects for an extension to adapt the FMI to the usage on automotive embedded real-time systems are summarized.