CAN frame decoder

NMEA 2000 layouts come from canboat, the open-source PGN database that Signal K server's NMEA 2000 input (canboatjs) is built on. Values are little endian; the top of a field's range means “not available” and the value below it “error”. SI units (rad, K, m/s, Pa, C) are shown with a friendlier conversion next to them.

Victron and MG Energy Systems also send proprietary register messages — Victron VREGs and MG MGREGs on PGN 61184 — for values with no standard PGN. The decoder names the registers from the makers' own documents (state of charge, cell min/max, BMS state, charge limits, device state and more). Where canboat marks a PGN's layout as unverified, the decoder says so; for the new Electric Energy Storage PGNs it uses the layout MG Energy Systems publishes instead.

Messages longer than 8 bytes travel as fast-packet frames. Paste the reassembled payload here, or the raw frames into the log analyzer, which puts them back together.

J1939: SAE's parameter database isn't public, so only engine parameters published in manufacturer manuals are decoded — engine speed and torque, load, coolant temperature, oil pressure, battery voltage, fuel level, engine hours — plus DM1 lamps and fault codes (SPN, FMI, occurrence count).

CANopen: NMT commands, heartbeat states, expedited SDO reads and writes with abort codes, and emergency messages with the error register. PDO contents depend on each device's mapping, so they're shown raw — decode them with the signal calculator.