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2 Tutorial: Exporting a Subsystem as a dSPACE Application
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This tutorial guides you through the process of creating a dSPACE model using a dSPACE Connector DS1104 template, from a pure closed-loop simulation model.
It is a rapid control prototyping application, where the controller runs in real-time on the DS1104 board in order to control a real system.
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2.1 Overview of the Plant to Control
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The model simulates the DC Motor speed controller. The system is composed of the following real components:
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The DC Motor itself, which includes a gear (ratio=30)
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The H-bridge driver, allowing the bi-directional control of the motor. This component also provides a current measurement output with a 377 µA/A sensitivity, connected in series with a 2 kΩ resistor
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A TTL incremental encoder with 300 lines. This encoder is attached to the motor shaft (the rotor), not to the gear shaft. Thus, there are 9000 lines (300*30) per revolution
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2.2 Overview of the Initial Closed-loop Simulation Model
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The initial closed-loop simulation model (DCMotorControl_startTutorial.msim) is located in the examples directory of the dSPACE Connector installation:
(<Maple 16>/toolbox/dSPACEConnector/data/examples, where <Maple 16> is your Maple 16 installation directory).
Open this model in MapleSim. The main components are (from right to left):
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The DC Motor model. You can explore this model to see the different parameters of the motor.
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A H-bridge subsystem, based on ideal switches and diodes components. The H-bridge, supplied with a 12V voltage source, provides the required power to the motor. Each switch is driven by a on/off signal output by the SignMagn subsystem.
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The SignMagn subsystem computes the switching logic in order to drive the H-bridge in the "Sign/Magnitude mode".
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The DutyCycle subsystem transforms the voltage command (output of the PID controller) into a direction and duty cycle signal, required by the Sign/Magnitude drive mode.
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A PID controller which maintains the real motor speed as close as possible to the reference.
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A pulse signal which gives the square speed reference.
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Run this model and look at the result.
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2.3 Preparing the Model for Export
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The model you opened in the previous section is not ready to export, mainly because it does not precisely reflect the real sensors and their interaction with the input and output components of the dSPACE DS1104 board. Next, you will add modeling components for the incremental encoder and the current sensor. You will also group into a subsystem all the components needed in the Controller application that will run in real-time on the DS1104 board.
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Adding the Incremental Encoder Model
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The output of the incremental encoder are pulses corresponding to the angular position of the rotor. In the real-time application, you will connect this sensor to the incremental encoder input of the DS1104 board. The encoder input driver of the DS1104 gives the angular position and the position difference between two time steps. Use this delta position to compute the speed.
To add the incremental encoder model
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Disconnect the line between the DCMotor speed output and the minus input of the comparator block.
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Add a gain block (from the Signal Blocks → Common palette) to the right of the DCMotor subsystem.
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Transform this block into a subsystem (select the block, then select Edit → Create Subsystem from the MapleSim menus). Name the subsystem "IncEncoder".
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Double-click on this subsystem to open it.
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Connect the input and output of the gain block to the subsystem boundary and name the input,"Speed" and name the output,"DeltaPos".
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Modify the gain value: since there are 9000 lines per revolution and that the sample time of the application will be 1 ms, multiply the real speed by  in order to get the delta position value.
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Connect the DCMotor speed output to the input of the "IncEncoder" subsystem.
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Processing the Incremental Encoder Capture Signal in the Real-time Application
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In the real-time application, you will need to transform the incremental encoder capture signal of the DS1104 board (delta position) into a quantity corresponding to the motor speed. For this you just need to add another gain block with a value which is the inverse of the one you set up in the previous section.
To process the Incremental encoder capture signal
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Add the gain block near the minus input of the comparator block (at the left of the PID subsystem)
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Create a subsystem with the name "IncEncoderScaling"
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The input and output of this subsystem will be respectively "DeltaPos" and "Speed"
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The gain value is 
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Connect the output of the "IncEncoder" subsystem to the input of the "IncEncoderScaling" subsystem.
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Connect the output of the "IncEncoderScaling" subsystem to the minus input of the comparator block.
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Converting the Controller to a Subsystem
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By converting your entire model or part of your model into a subsystem, you identify which parts of the model you want to export to a dSPACE application. In this example, you will group the controller components into a subsystem.
To convert the controller to a subsystem
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Using the selection tool (
) located above the Model Workspace, draw a box around the controller components in the model.
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From the Edit menu, select Create Subsystem.
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In the Create Subsystem dialog box, enter Controller as the subsystem name.
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Click OK. A Controller subsystem block is displayed in the Model Workspace.
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Open this subsystem and modify the names of the input and outputs as below:
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First input (connected to the comparator): "SpeedReference"
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Second input (connected to the IncEncoderScaling subsystem): "DeltaPos"
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First output (first output of the DutyCycle subsystem): "Direction"
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Second output (second output of the DutyCycle subsystem): "DutyCycle"
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Adding the current sensor model
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For the real-time application, connect the current sensor output to an analog input of the DS1104 board in order to monitor the current in the drive.
To add the current sensor model
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To save time, the current sensor model is already included in this model. You will find it in Project → Definitions → Subsystems, with the name "CurrentMeas".
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Remove the current probe in the model and put it below the DCMotor subsystem.
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Connect the DCMotor current output to the input of the "CurrentMeas" subsystem.
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Processing the current sensor ADC signal in the real-time application
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In the real-time application, connect the output of the current sensor to an ADC input of the DS1104 board and transform the signal into a quantity corresponding to the motor current. For this you just need to add a scaling gain block in the controller subsystem.
To process the current sensor ADC signal
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Open the Controller subsystem.
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Put a gain block (from the Signal Blocks → Common palette) below the other blocks of this subsystem.
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Connect the input of this gain block to the left border of the subsystem and give the name "Imeas" to the input.
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The current value will not be used in the controller (you just want to monitor it), so you will not connect it to any block of the controller. However, in order to generate code you cannot leave the output of the gain block unconnected. Thus you need to connect the output of this block to the right border of the subsystem and give the name "Current" to the output.
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Modify the gain value: since the sensitivity is 377 µA/A and since you get value through the voltage measurement on a 2 kΩ resistor, the scaling value is  .
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You will need also to monitor the motor speed in the real-time application. Thus you need to connect the output of the IncEncoderScaling subsystem to the right border of the subsystem and give the name "Speed" to the output.
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Delete the three probes. They will be added to Controller subsystem outputs in step 9.
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Go up one level to the Main model and connect the third input of the "Controller" subsystem to the output of the "CurrentMeas" subsystem.
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9.
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Add a probe to the first and second output of the "Controller" subsystem.
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You can leave the third and fourth output of the "Controller" subsystem unconnected or add a probe to display the values during a MapleSim simulation.
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This model should now be the same as the one you can find in the dSPACE Connector Examples palette. The "Controller" subsystem is now ready to be prepared to export. Note that you can still simulate this model in MapleSim.
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2.4 Map the Controller subsystem inputs and outputs to the dSPACE DS1104 inputs and outputs
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You will now define the mapping of the Controller subsystem inputs and outputs to the DS1104 hardware input and outputs, reflecting the real connection between the DS1104 and the DC Motor. This will be done using the Maple template, dSPACE_DS1104, which will then be attached to the model.
To map the controller
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Click Templates (
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From the list, select dSPACE_DS1104.
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In the Attachment field, enter dSPACE_DS1104_Controller as the worksheet name.
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Click Create Attachment. Your MapleSim model is opened in Maple, in the DS 1104 Code Generation template.
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Browse to the Controller1 subsystem by selecting the subsystem name from the drop-down menu in the toolbar above the model diagram.
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In the Subsystem Selection section of the template, click Load Selected SubSystem. All of the template fields are populated with information specific to the subsystem displayed in the model diagram.
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You can now define the mapping between the inputs and outputs of the subsystem and the dSPACE DS11014 inputs and outputs, according to the following details:
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The speed reference could be connected to a external signal generator signal. However, it can be interesting to run a virtual signal generator in real-time on the dSPACE board in order to tune the amplitude, frequency and/or offset directly from the dSPACE ControlDesk software. Thus, you will connect the speed reference input of the controller to a virtual square wave signal. The other choices for the virtual signals are Sine, Step or Constant.
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The incremental encoder of the DC Motor will be connected to the first incremental encoder input of the DS1104 board.
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Next, current sensor of the H-Bridge will be connected to the first ADC input of the DS1104 board.
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The direction input of the H-Bridge will be connected to the first digital output of the DS1104 board.
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The duty cycle input of the H-Bridge will be connected to the first PWM output of the DS1104 board.
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The current sensor signal monitored by the controller (third output of the controller) will be left unconnected.
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You will proceed in two steps. First you will define of all the mapping signals, and then you will configure the input and output parameters. To define all of the mapping signals, follow steps 9-14.
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In the Input / Output Settings for the dSPACE DS1104 Board section, Input Mapping table, select the Main.Controller1.SpeedReference(t) signal in the list of model inputs. In the DS1104 inputs or Virtual signals list box on the right, select virtual_Square_1. This signal will be replaced in the application by a square signal generator running on the dSPACE board.
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In the Input Mapping table, select the Main.Controller1.DeltaPos(t) signal in the list of model inputs. In the DS1104 inputs or Virtual signals list box on the right, select DELTA_INC1, which is the delta position information given by the first incremental encoder input of the DS1104 board.
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In the Input Mapping table, select the Main.Controller1.Imeas(t) signal in the list of model inputs. In the DS1104 inputs or Virtual signals list box on the right, select ADCH1. This signal will read the value of the first ADC channel of the DS1104.
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In the Output Mapping table, select the Main.Controller1.Direction(t) signal in the list of model outputs. In the DS1104 outputs list box at the right, select Bit_ch0. This signal will send the value computed by the application to the first digital channel of the DS1104. Note that the digital inputs and outputs of the DS1104 board can be configured either as inputs or outputs. In the present case, since the Bit_ch0 channel is defined as an output, it can no longer be used as an input. To verify this, browse the DS1104 inputs or Virtual signals list box and look for the Bit_ch0 signal. You will see that it is marked as unavailable. If you try to connect an input signal to this channel, you will get an error message, until you disconnect the channel from its output signal.
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In the Output Mapping table, select the Main.Controller1.DutyCycle(t) signal in the list of model outputs. In the DS1104 outputs list box on the right, select PWM_ch1. This signal will send the value computed by the application to the first single phase PWM channel of the DS1104.
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The Main.Controller1.Current(t) signal is left unconnected. Monitor it using ControlDesk.
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To configure the parameters
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To configure the Virtual Square Signal Generator, scroll down in the template and expand the Virtual Square Signals Generator section. In the Square 1 part of the table, enter 5 for the Amplitude value, 0.5 Hz for the Frequency and 10 for the offset.
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To configure the Incremental Encoder Interface, scroll up in the template and expand the Incremental Encoder Interface section. In the General parameters section, select the Encoder 1 mode as TTL. Since there is no index signal on this encoder, for reset on Encoder 1 index mode, click false. Leave the default value of 0 in the initial position of the encoder in the Initialization section as zero, since you will not be using the position capture.
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The ADC1 to which the current sensor is connected, has no configuration possibility. However, you can check the characteristics of this channels by scrolling up in the template and expanding the Mux ADC Unit section.
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To configure the first single phase PWM channel, scroll down in the template and expand the PWM Generation section. In the General parameters section, select the PWM mode as asymmetric, the PWM period as 2ms and the polarity as active high for the first channel. In the Initialization section, select 0 as the initial duty cycle for the first PWM channel (the initial speed of the motor should be 0). In the Termination section, select the Termination value radio button and select 0 as the termination duty cycle for the first PWM channel (for safety the termination speed of the motor should be 0).
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To configure the first digital I/O channel, scroll up in the template and expand the Bit I/O Unit section. In the Initialization and Termination section, you will notice that the first channel is marked as output, whereas the other channels are marked as unused. Select 1 as the initial value (corresponds to forward turn of the motor). In the Termination section, select the Hold the current value radio button. You want the termination direction of the motor be the same as it was just before the termination of the application.
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The I/O mapping and configuration is now complete. You can now proceed to the next step; exporting the controller to a real-time dSPACE application.
Note that you can attach more than one template of this kind if you need, for example, to define different I/O mapping for the same controller.
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2.5 Exporting the Controller to a dSPACE real-time application running on the DS1104 board
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In this section, you will create an dSPACE executable than can run on a DS1104, from the Controller subsystem.
To Export the Controller
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In the Options section, set the Solver Setting to a base sampling rate of 1 ms.
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In the Options section, set the Code Optimization option to Full. This option specifies the degree of simplification applied to the model equations during the code generation process. This option eliminates redundant variables and equations in the system.
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In the Options section, set the TRC Variables and Parameters Option to allow you to add all the possible parameters and/or variables in the TRC file that is generated with the dSPACE application. The TRC file is used by ControlDesk so that you can display variables and modify parameters on the running real-time application.
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In the Generate the dSPACE Application section of the template, specify the dSPACE directory and the directory where the application should be generated.
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Click Generate to dSPACE Application to generate the C code, the .trc file, the .sdf file and the .ppc file of the application.
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Open ControlDesk and load the generated application as usual. You will have access to the inputs, outputs, states and states derivatives of the application in the Model group. The parameters are in the Model Parameters subgroup, the execution time and current time can be accessed from the Task Info → Execution subgroup. Of course, this application should be connected to the real system so that you get interesting values.
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