Introduction

The Simcenter Amesim™ software package is a simulation platform that supports modeling from a variety of sources. It contains many libraries created using C, but it also supports Modelica ®. This manual will give an overview of Modelica and how Simcenter Amesim users can leverage it with the Modelica platform.

Modelica is a modeling language for describing dynamic systems. Modelica does not refer to a software tool, but only to the language itself. It is a system-level physical modeling language and can therefore be used to create multi-domain, system-level models, including their discrete as well as their continuous aspects.

Physical components can be defined as code written in Modelica, much in the same way that Simcenter Amesim native submodels are written in C. For example, this is a simple Modelica model that integrates a quantity v over time from some initial value x0:

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model Example1 "This is simple example"
       Real x(unit="m") "position";
       parameter Real v(unit="m/s") = 1 "constant
          speed";
       parameter Real x0(unit="m") = 10 "starting
        value of x";
       initial equation
       // This equation applies only at the
        start of the simulation
          x = x0 "initial position";
       equation
          // This is our main equation
          der(x) = v "the derivative of x is the quantity v";
    end Example1Fancy;

Modelica models can be built up in hierarchical fashion. For instance, a model developer might build circuit components, and then place multiple circuits into the same subsystem, creating a hierarchical model.

While a Glossary  has been provided to define several important terms, the Modelica language itself is too deep a topic to cover with any detail in this manual. Instead, we refer the reader to the Modelica Association website for more information about the language.  In particular the documentation page  includes the Modelica Language Specification (also available through Help), and the publications page contains links to several books, tutorials and technical papers. There are also several recommended Modelica books (both online and print) in the Bibliography of this manual.

The main purpose of this manual is to provide a high-level overview of how the Modelica platform works and how you can use it to create, compile, simulate and post-process Modelica models. This manual will not describe how every button/feature of the Modelica Editor works. There is a separate Modelica Editor manual focused on the detailed tool usage aspects.

The rest of this manual will focus on how you can create, modify, compile, simulate and post-process Modelica models. We will begin with a high-level overview of the process in the What is the Modelica platform? section. The Modelica platform in detail section provides a closer look at each step in the workflow. In the Advanced Modelica language topics section, several advanced topics are covered in detail. The current limitations of the tool are described in the Limitations section. Following that, some simple electromechanical examples are provided in the Simple examples section. Finally, a Bibliography, Glossary, and Index are provided at the end of this manual.