Functional Mockup Units (FMUs)

The following sections explain the use of FMUs in MTF. The full documentation can be found in the following locations:

• GitHub project page

• FMI documentation page

• FMI v2.x specification

• FMI v3.x specification

Introduction

A Functional Mockup Unit (FMU) is a tool-independent, self-contained program (part) or library along with specifications and definitions how the binary code is to be executed.

For more detailed information check the FMI introduction.

The Functional Mockup Interface (FMI) defines the various APIs needed to develop the FMUs themselves as well as the tool that can execute them.

FMU and FMI

In general the term FMU defines the ZIP-archive containing the binary code as well as the specifications, definitions, and APIs, whereas FMI is the interface how the specifications and definitions have to be organized and laid out in order for the FMU to be correctly executed.

FMI v2.x vs FMI v3.x

In order to fix some problems of the CoSimulation concept the following features were added:

• Event mode

• Early return

• Intermediate Update Model

Additionally the Scheduled Execution model has been added in FMI-3.0.

For detailed information check the respective FMI documentation.

Execution models (CS vs SE)

Whereas the FMUs based on the CoSimulation model must provide the solution method and algorithms additionally to their model description algorithms, the Scheduled Execution lets the master govern the time progression during the simulation. This provides some distinct advantages especially for concurrent simulation.

Fore more information check the CoSimulation and Scheduled Execution documentation.