pycan-plot

Graph CAN signals from a recorded candump log, decoded through a KCD database.

Installation

pip install -e .

Usage

pycan-plot capture.log -d database.kcd -s Status.Voltage -s Status.Mode -o plot.png

Signals are named Message.Signal, exactly as they appear in the KCD. With no -o, an interactive window opens instead.

Signals are drawn as steps by default, because a CAN signal holds its last received value until the next frame arrives. --line overrides that.

Examples:

# One module in stack position 2, clipped to twenty seconds of the capture
pycan-plot capture.log -d db.kcd -s Status.Voltage -p 0x02000000 -t 10..30 -o v.png

# Two signals on separate stacked axes, clipped by wall-clock time
pycan-plot capture.log -d db.kcd -s Status.Voltage -s Status.Mode \
    --split -t 08:25:40..08:26:10 -o both.svg

Exit codes

Exit code 3 reports which stack-position prefixes were present for the requested messages — usually the fastest way to spot a wrong -p.

Fish tab completion

An editable install writes the completion script automatically. To do it by hand:

_PYCAN_PLOT_COMPLETE=fish_source pycan-plot | source                                      # current shell
_PYCAN_PLOT_COMPLETE=fish_source pycan-plot > ~/.config/fish/completions/pycan-plot.fish  # persistent

Completion covers log files, KCD files, message and signal names pulled live from the KCD on the command line, and — once the log file is given — the stack-position prefixes actually present in that log.

License

pycan-plot is distributed under the terms of the GPL-3.0-or-later license.