CAN bus tools · runs in your browser

CAN log analyzer

Open a log from your boat's NMEA 2000 backbone, engine J1939 bus or a CANopen motor controller. See every message stream with its rate, filter, expand any message into decoded fields, and export to CSV. The file never leaves your computer.

or paste below ·Decode as

Loading the NMEA 2000 database…

Reads candump, PCAN-View .trc, Yacht Devices YDWG-02, Actisense / canboat CSV, Actisense N2K ASCII, Vector .asc and ID#data lines.

How it works

Supported formats: Linux candump (both -l files and screen output), Yacht Devices YDWG-02 raw, Actisense and canboat CSV (time,prio,pgn,src,dst,len,data), Actisense N2K ASCII, PCAN-View .trc (v1.x and v2.x), Vector .asc, and plain ID#data lines. The format is detected from the first lines.

NMEA 2000 fast-packet frames are reassembled by PGN, source and sequence number; J1939 / ISO 11783 transport-protocol transfers (TP.CM broadcast or RTS, then TP.DT) are reassembled into the message they carry — a multi-fault DM1, for example. Frames whose start is missing from the log are counted as incomplete.

Large logs are fine: a 200,000-frame log takes a second or two to read on a laptop. Only the rows you open are fully decoded; the CSV export decodes everything you've filtered.

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CAN frame decoder

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Signal bit calculator

Start bit, length, endianness, scale → value and back

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Sources & privacy

Everything is decoded in your browser — logs and frames are never uploaded. Message layouts come from these documents; where a source doesn't define something, the tools show the raw bytes rather than guess.

canboat — NMEA 2000 PGN database v9.0.0 (Apache License 2.0) — NMEA 2000 PGN layouts, lookups and fast-packet / ISO transport framing
DynaGen (Cattron) TOUGH Series J1939 Reference Manual 9M02-9252-A201 — J1939 engine PGNs/SPNs, DTC layout
Mecc Alte MxK CAN-Bus Technical Guide — J1939 DM1 lamp bits and values
Schneider Electric Machine Expert — IoDrvJ1939 FMI (ENUM) — J1939 FMI names
Faulhaber Communications Manual 7000.05050 (CANopen protocol description) — CANopen COB-IDs, NMT, heartbeat, SDO, abort codes, EMCY

The NMEA 2000 definitions are derived from canboat, © 2009–2026 Kees Verruijt, under the Apache License 2.0. NMEA 2000® is a registered trademark of the National Marine Electronics Association; canboat's definitions are reverse-engineered, not the official NMEA database. Check critical values against your equipment's documentation.