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Advanced API

A Julia style scripting API that handles low level API calls.

ModelicaSystem

ModelicaSystem

OMJulia.OMCSession
OMJulia.quit

Example

Let us see the usage of ModelicaSystem with the help of Modelica model ModSeborgCSTRorg

model ModSeborgCSTRorg
  // Model of original Seborg CSTR in ode form
  // author: Bernt Lie, University of Southeast Norway,November 7, 2017

  // Parameters
  parameter Real V = 100 "Reactor volume, L";
  parameter Real rho = 1e3 "Liquid density, g/L";
  parameter Real a = 1 "Stoichiometric constant, -";
  parameter Real EdR = 8750 "Activation temperature, K";
  parameter Real k0 = exp(EdR/350) "Pre-exponential factor, 1/min";
  parameter Real cph = 0.239 "Specific heat capacity of mixture, J.g-1.K-1";
  parameter Real DrHt = -5e4 "Molar enthalpy of reaction, J/mol";
  parameter Real UA = 5e4 "Heat transfer parameter, J/(min.K)";

  // Initial state parameters
  parameter Real cA0 = 0.5 "Initial concentration of A, mol/L";
  parameter Real T0 = 350 "Initial temperature, K";
  // Declaring variables
  // -- states
  Real cA(start = cA0, fixed = true) "Initializing concentration of A in reactor, mol/L";
  Real T(start = T0, fixed = true) "Initializing temperature in reactor, K";
  // -- auxiliary variables
  Real r "Rate of reaction, mol/(L.s)";
  Real k "Reaction 'constant', ...";
  Real Qd "Heat flow rate, J/min";
  // -- input variables
  input Real Vdi "Volumetric flow rate through reactor, L/min";
  input Real cAi "Influent molar concentration of A, mol/L";
  input Real Ti "Influent temperature, K";
  input Real Tc "Cooling temperature', K";
  // -- output variables
  output Real y_T "Reactor temperature, K";
  // Equations constituting the model
equation
  // Differential equations
  der(cA) = Vdi*(cAi-cA)/V- a*r;
  der(T) = Vdi*(Ti-T)/V + (-DrHt)*r/(rho*cph) + Qd/(rho*V*cph);
  // Algebraic equations
  r = k*cA^a;
  k = k0*exp(-EdR/T);
  Qd = UA*(Tc-T);
  // Outputs
  y_T = T;
end ModSeborgCSTRorg
using OMJulia
mod = OMJulia.OMCSession()
omcWorkDir = mkpath(joinpath("docs", "omc-temp"))  # hide
mkpath(omcWorkDir)                                 # hide
sendExpression(mod, "cd(\"$(omcWorkDir)\")")       # hide
ModelicaSystem(mod,
               joinpath("docs", "testmodels", "ModSeborgCSTRorg.mo"),
               "ModSeborgCSTRorg")

WorkDirectory

For each OMJulia.OMCSession session a temporary work directory is created and the results are published in that working directory. In order to get the work directory use getWorkDirectory.

getWorkDirectory

getWorkDirectory(mod)

Build Model

buildModel

In case the Modelica model needs to be updated or additional simulation flags needs to be set using sendExpression The buildModel API can be used after ModelicaSystem.

buildModel(omc)
buildModel(omc, variableFilter="a|T")

Get Methods

getQuantities
showQuantities
getContinuous
getInputs
getOutputs
getParameters
getSimulationOptions
getSolutions

Examples

getQuantities(mod)
getQuantities(mod, "T")
getQuantities(mod, ["T","cA"])
showQuantities(mod)

getContinuous(mod)
getContinuous(mod, ["Qd","Tc"])

getInputs(mod)
getOutputs(mod)

getParameters(mod)
getParameters(mod, ["a","V"])

getSimulationOptions(mod)
getSimulationOptions(mod, ["stepSize","tolerance"])

Reading Simulation Results

To read the simulation results, we need to simulate the model first and use the getSolution() API to read the results

simulate(mod)

The getSolution method can be used in two different ways.

  1. using default result filename
  2. use the result filenames provided by user

This provides a way to compare simulation results and perform regression testing

getSolutions(mod)
getSolutions(mod, ["time","a"])

Examples of using resultFile provided by user location

getSolutions(mod, resultfile="C:/BouncingBal/tmpbouncingBall.mat") //returns list of simulation variables for which results are available , the resulfile location is provided by user
getSolutions(mod, ["time","h"], resultfile="C:/BouncingBal/tmpbouncingBall.mat") // return list of array

Set Methods

setInputs
setParameters
setSimulationOptions

Examples

setInputs(mod, "cAi=100")
setInputs(mod, ["cAi=100","Ti=200","Vdi=300","Tc=250"])

setParameters(mod, "a=3")
setParameters(mod, ["a=4","V=200"])

setSimulationOptions(mod, ["stopTime=2.0", "tolerance=1e-08"])

Advanced Simulation

simulate

An example of how to do advanced simulation to set parameter values using set methods and finally simulate the "ModSeborgCSTRorg.mo" model is given below .

getParameters(mod)
setParameters(mod, "a=3.0")

To check whether new values are updated to model , we can again query the getParameters().

getParameters(mod)

Similary we can also use setInputs() to set a value for the inputs during various time interval can also be done using the following.

setInputs(mod, "cAi=100")

And finally we simulate the model

simulate(mod)

Linearization

linearize
getLinearizationOptions
setLinearizationOptions
getLinearInputs
getLinearOutputs
getLinearStates

Examples

getLinearizationOptions(mod)
getLinearizationOptions(mod, ["startTime","stopTime"])

setLinearizationOptions(mod,["stopTime=2.0","tolerance=1e-06"])

res = linearize(mod)

getLinearInputs(mod)
getLinearOutputs(mod)
getLinearStates(mod)

Sensitivity Analysis

sensitivity

Examples

(Sn, Sa) = sensitivity(mod, ["UA","EdR"], ["T","cA"], [1e-2,1e-4])
OMJulia.quit(mod) # hide