Dear Ankit Naik

Great presentation today! I kind request. If there is the opportunity, please talk about taking advantage of the large amounts of models that have been developed in Modelica language that can be imported from Wolfram SystemModeler.

Best regards

Jesus

Sure, I will. I plan to talk about it in Friday's session.

For people following this post and new to Modelica, you can learn about the Modelica language here: https://www.wolfram.com/system-modeler/resources/what-is-modelica/

I would like to ask a question, it is not clear to me in any system or subsytems, how many variables are "inputs" and how many "outputs" and where is this defined. I understand in a simulation all variables are then calculated for the entre time span

Hi Carl,

Not from System Modeler, but you can create such diagrams (Sankey diagram) using the Wolfram Language.

Once you are done with the simulation, you can extract the results from your simulation in Wolfram Language. Then use the results to create such diagrams. Here are some implementations that might be useful:

https://mathematica.stackexchange.com/questions/166439/how-to-make-a-sankey-diagram https://resources.wolframcloud.com/FunctionRepository/resources/AlluvialChart/

The easiest way of recognising inputs and outputs, for example, in a give component, is by looking at the connectors that are available in the icon of the component. Depending on the physical quantity, the connectors have different graphical representations. These are usually triangles of different colours.

In a broader sense, if you write your models, you can make any variable and input, output or none. When you make a variable input or output, there are some restrictions applied to it. For example, you will get an error when trying to connect outputs to outputs. It’s like an extra level of safety when creating your model.

All the variables are calculated when simulation is running, and the inputs will be calculated based on the output that you have connected to it. There is a special case, a top-level input, which is an input in the highest hierarchy of your model. In that case, if left unconnected, it will take a default value of zero.

Hi John,

Thank you!

1. I am not able to follow the question. To view the icon of a model or a component, you can open the model by double-clicking on it then press Ctrl + 1 to view the Icon and Ctrl + 2 to get back to the diagram view. You can refer to Step 1 in the Solution folder to check if your Step 1 in the Exercises folder matches it.

2. I will probably cover the new file creation and the .sme file on Thursday next week. No, there is no requirement to save the .sme file with the model files.

I am aware of some work going on in that direction. Hopefully, in a future release.

I guess the plot was already stored in the model and no new changes were made to it hence it is marked in black with no links.

1. Try deleting the default plot listed under the "Model Plots" section on the left, or

2. Add another variable to your plot, this will turn it blue with an option to "Update Plot in Model"

Hi,

That is because you don't have the Business Simulation library loaded. I will show you how to load it tomorrow.

If you don't want to wait, then you can already download it from this page: https://www.wolfram.com/system-modeler/libraries/business-simulation/

I have the same questions but I am waiting for them to get there. I noticed in the live presentations that The models were displayed on their version System Modeler. I will make the suggestion that in the future the class presenters start with the same "virgin" copy of the System Modeler so that we don't have to deal with the differences between what they see and what we see when we try to replicate it. It's a little confusing and time consuming to catch up. Educational once you figure it out. But less structured than maybe would be helpful.

I will try to cover this is today's session.

Ankit,

I found all the answers to my questions by reviewing the first class with the recording. It was because some important steps for beginners were missed.

Thank you for your consideration of my inquiries.

See you soon.. :)

P.S. It was me to request Wolfram to teach us this and some other courses and daily study groups that Wolfram had not taught us before. I do need to learn the skills, which was one of the biggest reasons for me to have learned Wofram Language through the classes and daily study groups. THANK YOU!

Hello Ankit, Thank you for sharing that file. Indeed, you created it after the most recent training session. It was sent to me then as well. Inspiring to say the least. At the time I was using version 13 of WM and SM so had to edited your file to work with those versions.

Still it's daunting to look through the Modelica files to understand how the equations of state were programmed, surely someone must have created a better documentation. I'll keep looking.

Great job, with this training. It's the best so far. John.

Hello Ankit,

So I am going back through the lectures slowly and running WL 14 and SM 14 and trying to replicate your steps to see what works and what does not. In lecture 2 when you got the the step where you entered

SystemModeler[modelName, ""]

Highlighting the quotes automatically gave you the options you could put in there - standard WL feature. But when I did that, nothing happened. When I typed it the word Diagram or Modeling the command worked as expected. I just did not get the list of options. When something like that happens, it often indicates the instructor is using a Beta of the next release of WL or SM. Are you? Or is something else going on you can help me with?

Carl

Hello Carl,
I'll try to help on this, if it continues not to work, please inform so Ankit can help further.

Starting from a fresh Kernel, ie Evalutation>Quit Kernel>StartKernel.
It works for me (WM 14, SM14) when I run this sequence of commands,

Text Line : Load the system modeling functionalities:

SystemModel;

Text LIne : Load the model diagram:

modelName = "ModelingPrinciples.Coffee.Exercises.Step1";

Now when you type the command below, on starting to type the Quotation mark, you will initially only see the leading Quote and the drop down menu of options to choose from. Once "Diagram" is selected the command is populated with "Diagram"

SystemModel[modelName, "]

Hope this was helpful,
John Burgers.

Thank you. Re-starting the kernel did the trick. Weird, that one. But the suggestions box is still generating the wrong syntax to remove the box. Is System Modeler is violating a Mathematica syntax rule? Or is the suggestion box violating a syntax rule? Have to come back the that...

Hi Soomi,

We will cover SystemModelCalibrate in tomorrow's session.

@Vedat Senol was sick last week. If he feels better then he should join from tomorrow.

Hi John,

In Simulation Center, go to File -> Save Experiment Settings -> Ok

K. Sorry about my own syntax violations there... I was cut and pasting my thoughts and I guess I cut when I should have pasted or something like that.

Hi Ankit:

Has the recording from today's session (Monday, April 15th) been posted? If so, I haven't received the email link yet to view it. I usually receive it shortly after the on-line session ends, but it's now 1810 CDT (Houston). I'm trying to keep up, so I'd like to view today's session and work through the examples before tomorrow's session. Like another participant, I need to frequently pause the recording to ensure I'm making the correct entries in System Modeler and get a better understanding of what's going on. Thanks to you and all the other presenters/support staff for all the excellent content.

Regards,

Jim Kralik

Hi Ankit,

Still no recording of yesterday's class is available (lol). I must study it before today's class. How can I do it?

THANK YOU, Ankit!

You are the best instructor ever!

In regard of the mass of CO2 in the atmosphere in the year 2002:

rs1 = Solve[
   Eliminate[{xCO2 == nCO2/nAir, mAir == nAir*MAir, 
     mCO2 == nCO2*MCO2}, {nCO2, nAir}], mCO2][[1]]

gives

{mCO2 -> (mAir MCO2 xCO2)/MAir}

With data from Wolfram Alpha and Mathematica:

UnitConvert[
mCO2 //. 
Join[rs1, {mAir -> 
WolframAlpha[
"mass of atmosphere", {{"Result", 1}, "ComputableData"}], 
MCO2 -> ChemicalData["CO2", "MolarMass"], 
MAir -> ChemicalData["Air", "MolarMass"], 
xCO2 -> UnitConvert[
WolframAlpha[
"global carbon dioxide concentration 2002", {{"Result", 4}, 
"ComputableData"}][[2, 3]]]}], "MetricGigatons"]

gives

Quantity[2915.77, "MetricGigatons"]

The recordings will be hosted in Wolfram U as on-demand videos after the study group is over.

You can use the following to represent infinity: Modelica.Constants.inf

Type it in the parameters field. You can also find all the other type of constants in the package: Modelica.Constants

While reviewing the "Different Models" session I would like to try the creation and simulation of the model based upon the business library. By chance do you have a list of parameters for those components? Thank you, John

... continuing on these are the parameters I chose to when investigating the model behaviour, by simulating and then plotting the energy stored in the material stock components and on a second plot the power passing through the proportionalTransition components. It almost makes sense. My engineering sense is that the proportionalTransition components daisy chain the inertia so the electrical output appears to ramp up after the gear box comes up to speed, where as in reality the gearbox and generator come to speed at the same rate. Given that most energy would be generated at controlled rotor speed the small proportion of energy generation during speed transition is insignificant for this business model.

see the attached file for the Component Names, BaseType, OutputType and Parameters. The component models types can be seen on the class video recording.

Attachments:

DifferentModelsW...txt

Not sure. That file was not used in the sessions. I will ask the our team to remove it.

Hey Ankit, Did I miss this? How do you save things in a Session in System Modeler / Simulation Center so that you can close them and reopen and pick up where you left off? Is there a way to do that? Carl Also, where can you go to get easy to use Modelica models for electronic components and subsystems like microwave components that can be loaded into System Modeler? Like Couplers, mixers, amplifiers etc? Do they even exist?

Hi Carl,

Sorry for the late reply. This post is currently inactive. You can create a new post in the System Modeler group for future queries.

1. I don't think you can save a session. For Simulation Center: If you are analyzing a plot by creating measurements or updating plot legends then you can save the plot as a Model Plot. This will save the updates in the model and you can resume later. You can also try to export the results as a Simulation Executable (I covered this on Thursday 18th April) and reload the simulation results later.
2. Unfortunately, I am not aware of a library that has microwave components. The only relevant library that comes to mind is Modelica.Electrical.Analog.