A bug about Packet output

I am encountering an issue where the Packet Out block from the Simulink Desktop Real‑Time toolbox fails to transmit CAN FD messages. I am using a PCAN‑FD‑USB adapter configured as shown in the attached settings. I packaged a 64‑byte CAN FD message, but another tool receives it as an 8‑byte classic CAN frame instead of a CAN FD frame. My suspicion is that the message‑type parameter passed to the PCAN API is incorrect.

Incidentally, the Packet Input block works correctly and can receive 64‑byte CAN FD data without problems.

This issue also persists in MATLAB R2026a.

[Torsten]

There are no settings attached.

I suggest you contact support:

https://uk.mathworks.com/support/contact_us.html

Answer 1

[Ishan]

The Packet Output block supports transmitting CAN FD messages when used with a CAN device configured in CAN FD mode and when the input is a CAN_FD_MESSAGE_BUS. The CAN FD protocol supports payloads up to 64 bytes.

Packet Output - Write binary data or a CAN message to a communication channel - Simulink

CAN Input/Output with Vehicle Network Toolbox - MATLAB & Simulink

CAN FD Pack - Pack individual signals into message for CAN FD bus - Simulink

If the Packet Output block is receiving a CAN_FD_MESSAGE_BUS containing a 64-byte payload and the receiving tool still reports an 8-byte classic CAN frame, then the behavior is unexpected.

Since the issue also occurs in R2026a and Packet Input can successfully receive CAN FD frames, I recommend contacting MathWorks Technical Support and providing:

• A minimal reproducible model
• MATLAB release
• PEAK-System driver version
• PCAN configuration settings
• A trace from the receiving tool showing the transmitted frame

This information will help determine whether the issue is related to configuration, driver interaction, or a software defect.