CANopen Bench

Web tool to test and control CANopen devices on a hardware bench — scan, object access, system tests, firmware download and a live CAN trace, driven by the devices' EDS files. Python backend (Starlette + canopen/python-can), no-build frontend (Preact/HTM), one self-contained workspace folder per bench.

Try it — no hardware needed

pip install canopen-bench
canopen-bench                  # → http://127.0.0.1:8000

No virtualenv needed to just run it. From a clone, pip install . installs the same thing from the checkout — without -e, which installs the package for editing, and that is what ## Development below is for.

canopen-bench is a shortcut the install writes; the module runs just as well by itself, and from a clone's root it runs that checkout:

python -m canopen_bench                       # same thing, same options
python -m canopen_bench --port 8001 --host 0.0.0.0

Two reasons to prefer it. It runs this directory rather than whatever canopen-bench happens to point at, which matters as soon as a second copy or a second virtualenv is around. And it needs only the dependencies, not the package itself: pip install starlette uvicorn websockets canopen python-can pyyaml (the dependencies list in pyproject.toml) and a clone is enough — worth knowing on a bench machine where you would rather not install anything.

Note the underscore: the distribution is canopen-bench, the module is canopen_bench. python -m canopen-bench cannot work — a hyphen is not valid in a Python module name.

Pick Demo mode on the Setup page, Connect, Scan: virtual devices are generated from the bundled canopen_bench/seed/DemoDevice.eds (installed into the workspace on first run). SDO reads/writes are answered from the EDS object dictionary — including realistic aborts on out-of-range writes — and every access shows up in the Trace like real bus traffic.

Features

• Setup — adapter/bitrate/scan-range, EDS registry with identity matching (0x1018), machine control: adopt the bench's expected state, scan & verify against it, re-address via exchangeable flow files.
• Production view: a switch to a reduced bench for the end of a line, showing the procedures a vendor package ships (flows marked grade: production, e.g. flash a board) with their firmware choices, a Start button, instructions and progress.
• Objects — EDS object browser with read/write, favorites (auto-saved), typed RAW rows (SDO / PDO / NMT with per-row node-id), last-known values per device serial number.
• Tests — declarative YAML test cases (docs/ablaeufe/testfall-format.md, examples in examples/testcases/) executed for real against the selected device. A run leaves HTML behind: one file per case, one summary, and a JSON sibling. From those, "Overview by variant" folds the last so many days into one collapsible section per hardware variant — runs, successes and last verdict per case — which is how you tell one broken variant from a broken device family.
• Bench instruments — a remote-controllable lab power supply is set from the Setup page and from a test case (psu step), which is what keeps an under-voltage case automated instead of asking an operator to turn a knob. Serial port, pip install ".[serial]"; drivers in canopen_bench/instruments/.
• SWDL — firmware download; the files come from a folder you point at (often the firmware project's build output, drag & drop works too), and what each one is comes from the extension that knows the format. Download protocols are manufacturer-specific and ship as vendor extension packages (see the note on the page).
• Trace — live monitor, newest frame at the top, scrollable back through the whole 200k-frame ring buffer or an opened capture rather than a screenful. Class + device filters, ms/µs timestamps, capture save/load, and autosave — every recorded frame written to a capture file as it arrives, kept for two weeks, for the endurance runs that are longer than the ring is deep.

Hardware

Which adapters the tool talks to, via python-can. Names are the manufacturers' — see the trademark note in THIRD-PARTY-NOTICES.md; this project is not affiliated with any of them, and the table says what has been exercised, not what is warranted.

Everything above demo mode goes through python-can's own backends, so adapter support tracks python-can. The Vector entry exists because plain CAN on a VN1600 needs only Vector's freely downloadable XL driver — the CANoe/CANalyzer licences are for their applications, not for talking to the hardware — and a lot of that hardware outlives the software budget it was bought with. Bring-up checklists live in docs/ablaeufe/A-01-verbinden.md and A-02-scan.md.

Workspaces

Every subfolder of the data folder is one workspace: its own sqlite db, EDS files, trace captures and flow files. Create and switch workspaces on the Setup page; copy a folder to clone or back up a bench. The data folder is chosen under Setup > Folders and kept per user (%APPDATA%\CANopen-Bench, ~/.config/canopen-bench), so the bench finds it wherever it is started from; on the first start it is ./data where there is one, else ~/CANopen-Bench. --data <folder> names it for one start (a second bench beside the everyday one, a mounted Docker volume). --db <path> remains as an expert override for a single explicit database file.

Flows and EDS files a package ships are written over in the workspace on every start, like its test cases: an update arrives without anybody looking for the old copy. A file of one's own goes in under another name.

Docker

docker build -t canopen-bench .
docker run -p 8000:8000 -v canopen-bench:/data canopen-bench

All workspaces live on the /data volume. Demo mode works out of the box; USB CAN adapters need the device passed through (--device=/dev/bus/usb). The tool has no authentication — keep the port on a trusted network (see SECURITY.md).

Extending

Vendor- and device-specific functionality (adapter cards, EDS seeds, firmware catalogs, addressing procedures with session identities, demo protocol simulations, trace decoders, EMCY code tables, custom test-step primitives, SWDL strategies) lives in separate pip packages registered under the canopen_bench.plugins entry-point group — installing one activates it. In multi-workspace mode this needs no shell at all: Setup > Extensions installs a plugin package (.whl) straight from the browser, active immediately — its own dependencies are not installed with it, and the state log names any this Python lacks, with the pip command that adds them. Guide with hook table and a minimal example: docs/extending.md; API: canopen_bench/plugin.py. A complete worked example ships in this repo under plugins/cob-cpcusb/ — python-can driver plus adapter card, its own tests, MIT. It is a separate distribution, not part of the canopen-bench package: install it only if you have that adapter.

Documentation

• IMPLEMENTATION.md — architecture and design decisions
• CONTRIBUTING.md — dev setup, test conventions, what goes where
• docs/extending.md — plugin guide
• docs/ablaeufe/ — operational sequence specs (German)
• docs/ablaeufe/testfall-format.md — YAML test-case format

Development

python -m venv .venv && . .venv/bin/activate
pip install -e ".[dev]"         # editable + pytest/ruff
pytest                          # core suite

CONTRIBUTING.md has the rest: what CI checks, where things belong, the versioning rule.

Behind a TLS-inspecting corporate proxy, pip fails with CERTIFICATE_VERIFY_FAILED on pypi.org: the proxy's CA is trusted by the operating system but not by the certificate bundle Python ships. On pip 23.2+, --use-feature=truststore makes pip use the OS store instead. On older pip that route is closed — it needs the truststore package, which also comes from pypi.org — so export the OS root certificates to a PEM and point pip at it with --cert, or set it once with pip config set global.cert <file>. Either way certificate verification stays on.

License & author

Core application: MIT (LICENSE). Plugin packages are licensed independently — vendor plugins proprietary, cob-cpcusb MIT. Bundled and depended-on third-party components, and the trademark note (CANopen® and CiA® belong to CAN in Automation e.V.; this is not a CiA-certified or CiA-affiliated tool), are listed in THIRD-PARTY-NOTICES.md.

Created by NobseVomBerg · unsix.de · GitHub