Import, Export, and Decode Vehicle Data

Import, Export, and Decode Vehicle Data

Import, decode, and export vehicle network log files in MATLAB using Vehicle Network Toolbox (VNT).

When to Use

• Reading .mf4/.mdf/.dat, .blf, .asc, or .txt vehicle bus log files
• Decoding raw CAN/CAN FD frames to signals via DBC or ARXML databases
• Demultiplex signals from raw CAN/CAN FD frames via DBC databases in the case of simple multiplexing (R2026a or earlier)
• Decoding LIN frames via LDF databases (R2025a+)
• Handling polymorphic return types from VNT read functions
• Writing MATLAB timetable data to MDF/MF4 files with mdfWrite
• Writing CAN/CAN FD message data to BLF files with blfwrite
• Converting unsupported timetable types (logical, categorical, cell, datetime columns) for MDF export

When Not To Use

• Simulink CAN configuration
• Live CAN channel access
• XCP/A2L workflows
• Demultiplexing of signals in the case of hierarchical or extended multiplexing
• Demultiplexing of signals via ARXML or LIN databases
• Writing LIN data to BLF (unsupported by VNT's blfwrite -- use MDF instead)
• Writing to ASC or TXT files (no canMessageExport exists -- use BLF or MDF instead)

Prerequisites

Before running any operations, determine the MATLAB version:

r = matlabRelease;
tok = regexp(r.Release, 'R(\d{4})([ab])', 'tokens');
matlabYear = str2double(tok{1}{1});
matlabLetter = tok{1}{2};

Before calling BLF/ASC/TXT import or CAN/CAN FD/LIN decode functions, call detect_matlab_toolboxes to confirm Vehicle Network Toolbox is installed. If unavailable, tell the user. Once confirmed in a session, do not re-check.

MDF functions (mdfRead, mdfChannelGroupInfo, mdfInfo, mdfChannelInfo) are base MATLAB (R2023a+) and do not require VNT. Do not use the deprecated mdf() object constructor -- always use the functional API. For reading all groups blindly, mdfRead alone is acceptable. To selectively read or inspect structure first, use mdfChannelGroupInfo or mdfInfo.

For R2026a and earlier, multiplexing is not natively supported in Vehicle Network Toolbox. Apply the demultiplexing modifications described below to decoded signals.