CAN Replay

Replay logged CAN messages

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Libraries:
Vehicle Network Toolbox / CAN Communication

Description

The CAN Replay block replays logged messages from a .mat file to a CAN network or to Simulink^®. You need a CAN Configuration block to replay to the network.

To replay messages logged in the MATLAB^® Command window in your Simulink model, convert them into a compatible format using canMessageReplayBlockStruct and save the result to a separate file. For more information, see Log and Replay CAN Messages.

Note

You need a license for both Vehicle Network Toolbox™ and Simulink software to use this block.

Replay Timing

The block replays messages using their original timestamps to synchronize with simulation time (for regular simulations) or wall-clock time (for replay to a physical network). Specifically, when the Simulink solver advances one time step, the block sends the messages whose timestamps belong to that time step. Therefore, it is important that the timestamps are consistent with the time range of the simulation. It is recommended to set the simulation start time to 0, and to shift the message timestamps so that the initial timestamp is 0.

For more information, see Start time (Simulink) and the example Log and Replay CAN Messages.

Other Supported Features

The CAN Replay block supports the use of Simulink accelerator and rapid accelerator modes. Using this feature, you can speed up the execution of Simulink models. For more information on this feature, see Acceleration (Simulink).

The CAN Replay block supports the use of code generation along with the packNGo function to group required source code and dependent shared libraries. For more information, see Code Generation.

Code Generation

Vehicle Network Toolbox Simulink blocks allow you to generate code, enabling models containing these blocks to run in accelerator, rapid accelerator, external, and deployed modes.

Code Generation with Simulink Coder

You can use Vehicle Network Toolbox, Simulink Coder™, and Embedded Coder^® software together to generate code on the host end that you can use to implement your model. For more information on code generation, see Generated Code Compilation (Simulink Coder).

Shared Library Dependencies

The block generates code with limited portability. The block uses precompiled shared libraries, such as DLLs, to support I/O for specific types of devices. With this block, you can use the packNGo function supported by Simulink Coder to set up and manage the build information for your models. The packNGo (Simulink Coder) function allows you to package model code and dependent shared libraries into a zip file for deployment. You do not need MATLAB installed on the target system, but the target system needs to be supported by MATLAB.

To set up packNGo:

set_param(gcs,'PostCodeGenCommand','packNGo(buildInfo)');

In this example, gcs is the current model that you want to build. Building the model creates a zip file with the same name as model name. You can move this zip file to another machine and there build the source code in the zip file to create an executable which can run independent of MATLAB and Simulink. The generated code compiles with both C and C++ compilers. For more information, see Code Compilation Customization (Simulink Coder).

Note

On Linux^® platforms, you need to add the folder where you unzip the libraries to the environment variable LD_LIBRARY_PATH.

Examples

Log and Replay CAN Messages

Log and replay CAN messages using MathWorks® Virtual CAN channels in Simulink®. You can update this model to connect to supported hardware on your system.

• Open Live Script

Ports

Output

CAN Msg — Replayed CAN messages

CAN_MESSAGE | CAN_MESSAGE_BUS

This output port contains a packed CAN message logged at that particular timestep, output as a CAN_MESSAGE or signal bus of type CAN_MESSAGE_BUS.

Data Types: CAN_MESSAGE | CAN_MESSAGE_BUS

f() — Function-call event output

function-call event

This port provides a trigger to a Function-Call subsystem when the block receives a new message. You can connect it to a Function-Call Subsystem (Simulink) to unpack and process the message.

Data Types: function-call event

Parameters

Tip

Configure your CAN Configuration block before you configure the CAN Receive block parameters.

File name — Path and name of MAT-file with messages

untitled.mat (default) | file name

Specify the name and path of the file that contains logged CAN messages that you can replay. You can click Browse to browse to a file location and select the file.

Variable name — Variable in MAT-file holding messages

ans (default) | variable

Specify the variable saved in the MAT-file that holds the CAN message information.

Number of times to replay messages — Repeat value

Inf (default) | integer

Specify the number of times you want the message replayed in your model. You can specify any positive integer, including Inf. Specifying Inf continuously replays messages until simulation stops.

Replay messages to — Specify output location

CAN Bus (default) | Output port

Specify if the model is replaying messages to the CAN network or an output port. When replaying to the CAN network, you must also select a Device.

Device — CAN device and channel

device list option

Select the device on the CAN network to replay messages to. This field is unavailable if you select Output port for the Replay message to parameter.

Sample time — Block execution rate

0.01 (default) | numeric

Specify the sampling time of the block during simulation. This value defines the frequency at which the CAN Replay block runs during simulation. If the block is inside a triggered subsystem or to inherit sample time, you can specify –1 as the sample time. You can also specify a MATLAB variable for sample time. The default value is 0.01 simulation seconds. For more information, see Timing in Hardware Interface Models.

Output as bus — Enable signal bus output

off (default) | on

Select this option for the block to output CAN messages as a Simulink bus signal. For more information on Simulink bus objects, see Composite Interfaces (Simulink).

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

This block generates code with limited portability that runs only on the host computer. See Code Generation.

Version History

Introduced in R2011b