Notes about FMI support about blockfactory HOT 10 OPEN

Comparison of S-Functions and FMUs:

• https://en.wikipedia.org/wiki/Functional_Mock-up_Interface#Comparison_to_Simulink_S-Functions
• Chapter 4 (in particular section 4.3) of http://lup.lub.lu.se/student-papers/record/8847501/file/8859310.pdf
• Section 2.3.2 of https://www.computoolable.nl/P7a.pdf
• Section 3.4 of http://www.ep.liu.se/ecp/132/057/ecp17132507.pdf (limited to Clock/discrete time systems, a new feature that will be part of FMI 3)

from blockfactory.

• Code-based configuration vs file based configuration

  • In Simulink S-Functions and consequently in blockfactory, several configuration info such as the number of the ports, etc etc are specified by calling specific methods (in particular setIOPortsData in the configureSizeAndPorts method). In FMI, this information are specified in the XML file. To handle this, possible solutions are (the last one is my favorite):

    • Duplicate this info in handwritten XML files for FMUs (yuk)
    • Change how this info is specified (invasive)
    • Generate the XML files after the build by running a program that invokes the configureSizeAndPorts method of the block to wrap as FMU (this will be problematic when cross-compiling, but it seems that easy solution for now)

  • TL;DR: Handle how to generate XML files for FMU block

from blockfactory.

PR adding some part of the array support to the FMI standard: modelica/fmi-standard#543 .

from blockfactory.

Generate the XML files after the build by running a program that invokes the configureSizeAndPorts method of the block to wrap as FMU

Interestingly, part of this solution could be eventually re-used to automatize the existing manual process of writing the .slx file of the block library (i.e. the one described in https://robotology.github.io/blockfactory/mkdocs/create_new_library/#create-an-new-simulink-library).

As you can check by manually inspecting an .slx file, and by reading in https://stackoverflow.com/questions/23408186/information-about-simulink-mdl-and-slx-formats, the .slx is just a .zip file that contains a bunch of .xml (and some other format) files. A complete parser for reading/writing .slx does not seem to be available or feasible, but perhaps it could make sense to have a "template" .slx that can be be configured based on the library blocks' and ports.

from blockfactory.

Having a templated slx imho does not simplify that much the creation / maintenance of a Simulink Library, it is usually a trivial step from the GUI. I am pretty sure that Matlab (even the cli version) has some functions to automatize it without dealing with the file formats.

The main problem are the masks, the have to be developed from the GUI. I'm afraid that operating only on the slx or mdl would never be enough :/

from blockfactory.

      <Block BlockType="S-Function" Name="Signal Math" SID="1">
        <P Name="Ports">[2, 1]</P>
        <P Name="Position">[335, 69, 470, 116]</P>
        <P Name="ZOrder">1</P>
        <P Name="FunctionName">BlockFactory</P>
        <P Name="Parameters">&apos;SignalMath&apos;,&apos;ExampleToolbox&apos;,operation</P>
        <P Name="SFunctionDeploymentMode">off</P>
        <P Name="EnableBusSupport">off</P>
        <P Name="SFcnIsStateOwnerBlock">off</P>
        <Mask>
          <Display RunInitForIconRedraw="off">disp(&apos;Signal Math&apos;)

port_label(&apos;input&apos;,1,&apos;Input 1&apos;)
port_label(&apos;input&apos;,2,&apos;Input 2&apos;)

port_label(&apos;output&apos;,1,&apos;Output&apos;)</Display>
          <MaskParameter Name="operation" Type="popup" Evaluate="off">
            <Prompt>Operation</Prompt>
            <Value>Addition</Value>
            <TypeOptions>
              <Option>Addition</Option>
              <Option>Subtraction</Option>
              <Option>Multiplication</Option>
            </TypeOptions>
          </MaskParameter>
        </Mask>
      </Block>

from blockfactory.

We can probably move this discussion in a separate issue, btw.

from blockfactory.

We can probably move this discussion in a separate issue, btw.

👍

from blockfactory.

Simulink related discussion moved to #10 .

from blockfactory.

Interesting paper on FMI interface with a real time communication protocol (in this case RabbitMQ): https://github.com/INTO-CPS-Association/rabbitmq-fmu-documentation/blob/e6e57da07394858bc1519ef7b746df8459123ed6/rabbitmq-fmu.pdf , similar to how BlockFactory is used with YARP.

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