User manual

This argument, default being true, can be set to false to disable the prompting before

replacing any existing Modelica model that was the result from a previous import. This is

useful for scripting.

Import of FMUs for Co-Simulation

The Co-Simulation FMU import is enabled by setting the input argument

integrate of the

function

importFMU to false. The macro step size can be set as the parameter

fmi_CommuncationStepSize in the FMI tab in the parameter dialog of the generated

Modelica model. The default macro step size is (stop time – start time)/500. Refer to the

next section for details.

Validating FMUs

Once the dynamic behavior of a model is verified and it is ready to be exported as FMU, one

would like to verify that this behavior can be repeated on the targeted simulation

environment. For model exchange, which is dependent on the solver of the target, this is

naturally less straight-forward than for co-simulation, where the solver is built into the

FMU. We focus this discussion on the co-simulation case, although all is possible for model

exchange as well.

Normally, the FMU contains inputs that need to be connected to signal generators (sources)

before this validation can be commenced. Since this is model and test dependent and hard to

automate, we will assume the model inputs have been connected to necessary sources

beforehand. The result is a test model with no disconnected inputs. After the validation,

these sources are of course removed before the final FMU is created.

Since Dymola supports FMU import, it becomes natural to re-import the FMU in Dymola

and compare its simulation with the original model. We demonstrate this for the demo

model CoupledClutches. For brevity and since not all import options are yet available in the

GUI, we use a scripting perspective. First, export as FMU with, say, both model exchange

and co-simulation support:

translateModelFMU(

"Modelica.Mechanics.Rotational.Examples.CoupledClutches",

false, "", "1", "all");

Re-import, in a non-interactive mode, the FMU for co-simulation:

importFMU(

"Modelica_Mechanics_Rotational_Examples_CoupledClutches.fmu",

true, false, false);

Simulate the model being the result of the import:

simulateModel(

"Modelica_Mechanics_Rotational_Examples_CoupledClutches_fmu",

stopTime=1.5, method="dassl");

The import of FMUs for Co-Simulation functionality is currently intended for validating export of Co-Simulation

FMUs created in Dymola by re-importing them to Dymola. Importing Co-Simulation FMUs from other vendors has

not been tested due to no such FMUs being currently available.