Xcos

Xcos (from Scilab) is a graphical dynamical system modeler and simulator. Users can create block diagrams to model and simulate the dynamics of hybrid dynamical systems both continuous and discrete time.

RaspInLoop uses the Functional Mockup Interface (FMI) to communicate with such a simulator and the eclipse’s debugger. Xcos doesn’t provide module pre-installed to use FMI. We have to install it by ourselves.

The module is called “Xcos FMU wrapper” and is available on the scilab forge. Unfortunately, support for FMI 2.0 (which is required for RaspInloop) is still on development. So installation won’t be so easy.

Let’s start:

Download lastest sources of the “Xcos FMU wrapper” module in zip https://forge.scilab.org/index.php/p/fmu-wrapper/source/download/master/ Be sure to download latest version(~ 2016-11-22 ) which include support fro FMI 2.0 (and scilab 6.0 if you use it)

Unzip in a local directory. ex: C:\Users\Fred\Documents\RIL\fmu-wrapper-master

Then, open scilab, type

cd C:\Users\Fred\Documents\RIL\fmu-wrapper-master
exec('C:\Users\Fred\Documents\RIL\fmu-wrapper-master\builder.sce',-1)
exec('C:\Users\Fred\Documents\RIL\fmu-wrapper-master\loader.sce',-1)

You can now start xcos You should have a new entry in you “palette browser”

Note: to avoid to load module manually at every startup, you could add this:

cd C:\Users\Fred\Documents\RIL\fmu-wrapper-master
exec('C:\Users\Fred\Documents\RIL\fmu-wrapper-master\loader.sce',-1)

in your C:\Users\Fred\AppData\Roaming\Scilab\scilab-5.5.2.scilab file.

Finally

You may then, drop the FMInterface block into your diagram. Double click on the block to select the previously saved FMU (see tuto)

Once selected the Block will reflect input/output defined in FMU

Some examples are distributed with Pi4J jar. One of the simplest is BlinkGpioExample : led1 blinks every 1/2 seconds during 15 seconds and led2 blinks every second but speed up the rate when button is pressed.

Standalone Simulation Mode

Unlike the first tuto, where we used Ptolemy II (The Ptolemy Project) as a Computed Simulation Environment to drive our debug session, we will choose the standalone simulation mode. The standalone simulation mode uses an internal and configurable time sequencer. You just have to choose the simulation duration (End Time), the simulation precision(Time Increment) and whether the time must be speed up or slow down.(Time Ratio)

Debug Configuration

After installing (see getting started) and creating your project in eclipse, you have to set up your debug configuration:

Then Right click on RIL-Simulate and choose new configuration

Board configuration

You now need to choose which hardware you want to use. Even with a single Raspberry Pi board, there is a lot of different configurations. In this example, GPIO1 and GPIO3 are used as outputs and GPIO2 is an input.

So, click on “Configure Board”, in the “Manage Hardware list” click on “Add…”

Name your new hardware, check GPIO 1 and 3 as outputs, 2 as input and leave the other unused and save it.

Standalone settings

Choose stand alone as Simulation Mode and choose

Then, “Debug” !!

Results

The output console should display this :

<--Pi4J--> GPIO Blink Example ... started.
 ... the LED will continue blinking until the program is terminated.
 ... PRESS <CTRL-C> TO STOP THE PROGRAM.
2016-03-30 15:38:50 INFO  TimeSequencer:93 - Simulated Time: Duration[60.0 s], StepIncrement[0.001 s], Ratio[0.1]
2016-03-30 15:38:50 INFO  TimeSequencer:137 - Value for GPIO 1 @0,00: true
2016-03-30 15:38:50 INFO  TimeSequencer:137 - Value for GPIO 3 @0,00: true
2016-03-30 15:38:50 INFO  TimeSequencer:137 - Value for GPIO 1 @0,56: false
2016-03-30 15:38:50 INFO  TimeSequencer:137 - Value for GPIO 1 @1,04: true
...
2016-03-30 15:38:51 INFO  TimeSequencer:137 - Value for GPIO 3 @58,44: true
2016-03-30 15:38:51 INFO  TimeSequencer:137 - Value for GPIO 3 @59,92: false
2016-03-30 15:38:51 INFO  Handler:75 - Stop Called
2016-03-30 15:38:51 DEBUG Handler:66 - main was stopped: null

You can the change of each output with the number of second since the simulation start and the value of the output.

Some examples are distributed with Pi4J jar. One of the simplest is BlinkGpioExample : led1 blinks every 1/2 seconds during 15 seconds and led2 blinks every second but speed up the rate when button is pressed.

Eclipse Debug Configuration

After installing (see getting started) and creating your project in eclipse, you have to set up your debug configuration:

Then Right click on RIL-Simulate and choose new configuration

Board configuration

You now need to choose which hardware you want to use. Even with a single Raspberry Pi board, there is a lot of different configurations. In this example, GPIO1 and GPIO3 are used as outputs and GPIO2 is an input.

So, click on “Configure Board”, in the “Manage Hardware list” click on “Add…”

Name your new hardware, check GPIO 1 and 3 as outputs, 2 as input and leave the other unused and save it.

export fmu

Choosing “Functional Mockup Unit” as Simulation Mode allows you to get the FMU file. Click on the button and choose the location where the file will be saved.

I have chosen : C:\Users\Fred\workspace\RIL-Tuto\RaspberryPi GPIO Simulator.fmu

Ptolemy Project

We will use Ptolemy II (The Ptolemy Projecy) as Computed Simulation Environment. This was the first (and currently the only one) tool I have tested with FMU co-simulation. Meanwhile, the FMI standard publish a compatibility table showing which tool is able to use FMU in master co-simulation.

Download and install Ptolemy II

Then Download the sample Ptolemy Project : www.raspinloop.org/data/Ptolemy_blinkGpioExample.xml and open it in Ptolemy:

file -> Open File and select the previously downloaded Ptolemy_blinkGpioExample.xml

The project consists of 4 different parts:

• The Director
• Input signal generation
• The FMU binding
• Output Visualization

The Director

Ptolemy II is based on a class of models called actor-oriented models , or more simply, actor models. Actors are components that execute concurrently and share data with each other by sending messages via ports.

The director is responsible to coordinate dataflow through port of each block. Continuous director is able to compute in each iteration, a fixed point for all signal values. In each iteration, time is advanced by an amount determined by the solver. (see Ptolemy getting started)

Our configuration for the Step size is :

stopTime : 30 The simulation stops after 30 seconds

initStepSize : 0.005

maxStepSize : 0.005

So, each iteration will represent 0.005 seconds. An interresting parameter could be synchronize to realtime. With this option each iteration will occurs evrey 0.005 second instead of ‘as soon as possible’.

Input signal generation

On the left part of the schema, we put a Squarewave generator to simulate the button signal. This was done with a sinewave generator and a comparator to set a signal to true when sinus is positive and false otherwise.

TriggeredSinewave is configured like this:

frequency : 0.1 0.1 Hertz means positive for 5 seconds positive and negative for the other 5 seconds…

The FMU binding

This is the Main block. This block is the FMU (functional mockup unit) of Raspberry Pi. It will behave like all other blocks, with their inputs and output. Excepting of, this block will communicate with Eclipse to allow the java application to read inputs and set outputs.

To configure it, we have to import FMU file it in Ptolemy:

DO NOT CHECK : Import for model exchange

We may ‘wire’ GPIO2_i to the wire outgoing from Squarewave generator.

Output Visualization

In order to view the output, we use a block called timePlotter. This block doesn’t accept boolean as input, so we have to add a BooleanToAnything converter between FMU output and the plotter.

Now you may ‘wire’ your output to the converters

Note: You have to add another conveter to be able to wire the GPIO3. (try crtl-c -> ctrl-v)

You should have something like that….

RUN !

Now , we have to start your project in eclipse debugger (see install), wait for the message INFO [Server] Starting the simple server... and Run the model in ptolemy.

I hope you ‘ll feel the same exaltation as me seeing this graph.

Pens:

• red: the input to GPIO02
• blue: the GPIO1 output (led1 // continuously blink the led every 1/2 second for 15 seconds)
• cyan: the GPIO3 output (led2 // continuously blink the led every 1 second except when button is pressed -> speed up the blink rate)

Ptolemy Project

We will use Ptolemy II (The Ptolemy Project) as Computed Simulation Environment. This was the first tool I have tested with FMU co-simulation. Meanwhile, the FMI standard publish a compatibility table showing which tool is able to use FMU in master co-simulation.

Download and install Ptolemy II

Then Download the sample Ptolemy Project : www.raspinloop.org/data/Ptolemy_blinkGpioExample.xml and open it in Ptolemy:

file -> Open File and select the previously downloaded Ptolemy_blinkGpioExample.xml

The project consists of 4 different parts:

• The Director
• Input signal generation
• The FMU binding
• Output Visualization

The Director

Ptolemy II is based on a class of models called actor-oriented models , or more simply, actor models. Actors are components that execute concurrently and share data with each other by sending messages via ports.

The director is responsible to coordonate dataflow through port of each block. Continuous director is able to computes in each iteration, a fixed point for all signal values. In each iteration, time is advanced by an amount determined by the solver. (see Ptolemy getting started)

Our configuration for the Step size is :

stopTime : 30 The simulation stops after 30 seconds

initStepSize : 0.005

maxStepSize : 0.005

So, each iteration will represent 0.005 seconds. An interresting parameter could be synchronize to realtime. With this option each iteration will occurs evrey 0.005 second instead of ‘as soon as possible’.

Input signal generation

On the left part of the schema, we put a Squarewave generator to simulate the button signal. This was done with a sinewave generator and a comparator to set a signal to true when sinus is positive and false otherwise.

TriggeredSinewave is configured like this:

frequency : 0.1 0.1 Hertz means positive for 5 seconds positive and negative for the other 5 seconds…

The FMU binding

This is the Main block. This block is the FMU (functional mockup unit) of Raspberry Pi. It will behave like all other blocks, with their inputs and output. Expect that , this block will communicate with Eclipse to allow the java application to read inputs and set outputs.

To configure it, we have to download the Raspberry_b.fmu (currently only the B model) www.raspinloop.org/data/fmu/raspberry_b.fmu then import it in Ptolemy:

DO NOT CHECK : Import for model exchange

As explained in the warning, the imported actor as a lot of variables, it is up to us to select which of them we want to see as port. So Select FMU -> right click -> Customize -> Port

We have to uncheck ALL outputs except GPIO1, GPIO3 which should be visible (uncheck hidden) and to uncheck ALL inputs except GPIO2_i which should also be visible.

We may ‘wire’ GPIO2_i to the wire outgoing from Squarewave generator.

Output Visualization

In order to view the output, we use a block called timePlotter. This block doesn’t accept boolean as input, so we have to add a BooleanToAnything converter between FMU output and the plotter.

Now you may ‘wire’ your output to the converters

Note: You have to add another conveter to be able to wire the GPIO3. (try crtl-c -> ctrl-v)

You should have something like that….

RUN !

Now , we have to start your project in eclipse debugger (see install), wait for the message INFO [Server] Starting the simple server... and Run the model in ptolemy.

I hope you ‘ll feel the same exaltation as me seeing this graph.

Pens:

• red: the input to GPIO02
• blue: the GPIO1 output (led1 // continuously blink the led every 1/2 second for 15 seconds)
• cyan: the GPIO3 output (led2 // continuously blink the led every 1 second except when button is pressed -> speed up the blink rate)