Header Assignment

R2026b

Update fields of ROS message header

• 

Header Assignment block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
ROS Toolbox / ROS

Description

The Header Assignment block updates the values in the header field of a ROS message. When a ROS message contains a header field of type std_msgs/Header, you can use this block to update the frame_id and stamp values in its header field. During each sample hit, the block updates the frame_id and stamp fields in the header. The accuracy of the timestamp depends on the step size of the solver. Smaller step sizes result in more accurate timestamps.

Examples

Update Header Field of a ROS Message in Simulink

Update the header field of a ROS message using Simulink^®.

• Open Live Script

Read and Apply Transformation to ROS Message in Simulink

Read transformations from a ROS network and use them to transform a pose message using Simulink®.

• Open Live Script

Ports

Input

InputMsg — ROS message to update

nonvirtual bus

ROS message with a std_msgs/Header field, specified as a nonvirtual bus.

Data Types: bus

Output

OutputMsg — ROS message with an updated header

nonvirtual bus

ROS message with an updated header, returned as a nonvirtual bus.

Data Types: bus

Parameters

Set Frame ID — Specify frame associated with message data

off (default) | on

Select this parameter to specify the frame that the message data is associated with. Specify the frame ID in the text box enabled when you select this parameter. The block populates the frame_id field of the ROS message header with the specified frame.

Example: base_link

Set Timestamp — Set timestamp in header

off (default) | on

Select this parameter to set the stamp value of the header to the current ROS system time. In order to use the custom time published on the /clock topic instead of the ROS system time, set the use_sim_time ROS parameter to true.

Header field name — Specify Header field name

Use the default Header field name (default) | Specify your own

Specify the name of the Header field as one of the following:

• Use the default Header field name — The block sets the name of the header field in the ROS message to the default value, Header.

• Specify your own — Enables a text box in which you can specify a custom name for the header field in the ROS message.

Example: my_custom_header

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"robotlib/Header Assignment"

Example: add_block("robotlib/Header Assignment","myModel/myBlock",MakeNameUnique="on")

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2021a