CODEWITHSUNDEEP
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falsterbo
falsterbo

Reputation: 550

OpenModelica updating CombiTable input in real time

I have a model in which I am using a CombiTable1D to retrieve an external input from a .txt file. The file is generated by a Python script at the moment but in the final phase of the project, it is going to be updated each second. For now, simulation takes place without a problem as the .txt file is static. Just read the file and make simulation according to the data written there.

What I want to do is to simulate a model until a certain time, let's say 100s, and then make it wait until a real time event by which the .txt file is updated for the next external input values between 100-200. The simulation should continue by getting these new values for the next 100 seconds.

As I have already been working with OMPython, it is really practical for me to edit the .txt file using Python, let's say for each 10 seconds in real time. I can now simulate the model until the time instance that I define as the refreshing point of the external input. But I couldn't figure out how to keep the state of the simulation and make it read the file once again.

Upvotes: 2

Views: 577

Answers (2)

falsterbo
falsterbo

Reputation: 550

In addition the the answer I accepted, I want to give another solution which is not so efficient. For a simple model with a capacitor and resistor, I made successfull tests but with more complex models, it doesn't function properly. In a Modelica script, realTimeSimulation.mos:

outputFile := "stepResult.mat";
simulation_step := 1;
start_time := 0;
stop_time := start_time+simulation_step;
loadFile("WhereverTheFileIs.mo");
buildModel(myTestModel);
system("myTestModel-override=startTime="+String(start_time)+",stopTime="+String(stop_time)+" -r="+outputFile);

will build the model and simulate the first step until the simulation time t=1s. Later on, using Python the text file is updated. The new data for the time between t=1s and t=2s are written to the text file where I am getting the input of the model. Then another step of the simulation is made for the time between t=1s and t=2s. As a loop, it continues like forever like: actualize the data, make new simulation for the new time interval. The trick is, reading the output file created at the end of each step and giving all the variable values as the new initial conditions to the simulation, using following script:

valueList := readSimulationResultVars(outputFile);
start_time := start_time+simulation_step;
stop_time := stop_time+simulation_step;
value := val(OpenModelica.Scripting.stringVariableName(valueList[1]),start_time,outputFile);',
variableString := valueList[1] + "=" + String(value);

for i in 2:size(valueList,1) loop
value := val(OpenModelica.Scripting.stringVariableName(valueList[i]),start_time,outputFile);
variableString := variableString + "," + valueList[i] + "=" + String(value);
end for;

system("myTestModel-override startTime="+String(start_time)+",stopTime="+String(stop_time)+",variableString+" -r="+outputFile);

Upvotes: 0

tbeu
tbeu

Reputation: 1349

Actually, this sounds like a co-simulation scenario to me. Anyway, what you could do is to extend from CombiTable1D and have something like

block CombiTable1DWithUpdate
  extends Modelica.Blocks.Tables.CombiTable1D(final tableOnFile=true);
  algorithm
    when sample(0, 10) then
      readTableData(tableID, /* force update */ true, verboseRead);
    end when;
end CombiTable1DWithUpdate;

Upvotes: 3

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