Dynamically Change CAN IDs by CAN Pack Block Input Ports

Open Live Script

This example shows how to dynamically control the CAN identifier (CAN ID) provided to the CAN Pack block by specifying the CAN ID through an input port.

Using this method, messages are dynamically packed with varying CAN IDs.

Explore the Model

model = 'demoDynamicCANID'; 
open_system(model);

The model is structured to demonstrate the flow of messages from packing to transmission over a virtual CAN network. Key components include:

CAN Pack block: Configured to accept CAN IDs dynamically through an input port, facilitating the flexible packaging of CAN messages.
CAN Transmit block: Serves as the gateway for sending packed messages into the virtual CAN network.
CAN Configuration block: Configures parameters for a CAN device that you can use to transmit and receive messages.
Step block: Provides a varying input to the CAN Pack blocks.

Inspect the CAN Pack Block

Double-click the CAN Pack block to open its parameters dialog. Select the option Specify CAN identifiyer from input port.

Enabling this checkbox adds a new input port, allowing for the provision of changing CAN IDs dynamically.

Set Up CAN Transmit Block

The messages are packed and sent to a CAN Transmit block, which is connected to MathWorks® virtual channel 1.

Create a CAN Channel in MATLAB

To receive these messages and observe them, use MathWorks virtual channel 2.

rxCh = canChannel('MathWorks', 'Virtual 1', 2);

Start the receive channel.

start(rxCh);

Simulate the model.

sim(model);

Receive the messages in a time table format.

rxMsg = receive(rxCh, Inf, "OutputFormat", "timetable")

rxMsg=11×8 timetable
       Time       ID    Extended       Name              Data            Length      Signals       Error    Remote
    __________    __    ________    __________    ___________________    ______    ____________    _____    ______

    1.8717 sec    1      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    2.8777 sec    1      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    3.8816 sec    1      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    4.8831 sec    1      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    5.8903 sec    1      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    6.8906 sec    5      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    7.8868 sec    5      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    8.8831 sec    5      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    9.8793 sec    5      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    10.876 sec    5      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false 
    11.874 sec    5      false      {0×0 char}    {[8 0 0 0 0 0 0 0]}      8       {0×0 struct}    false    false

Observe the change in CAN ID in the recived messages.

stop(rxCh);

To visualize the varying CAN ID, plot the CAN IDs received.

plot(rxMsg.Time, rxMsg.ID);
hold on
data = vertcat(rxMsg.Data{:});
plot(rxMsg.Time, data(:,1));
hold off
xlabel("TimeStamp");
ylabel("CAN ID Value");
legend("CAN ID","Data","Location","northeastoutside");
legend("boxoff");
yMax = max(rxMsg.ID)+5;
ylim([0 yMax]);