glenn schrooyenandClaude Opus 5 d5c1577212
checks / unit (pull_request) Successful in 4m48s
SAFETY-30: pin WHICH thresholds each sign detector is armed with, not just what the numbers are
REVIEW FOUND A MUTATION SURVIVOR THAT UNDOES THE WHOLE PRODUCT OF AC 5, and it
is a coverage defect rather than a behaviour one - the shipped code arms the
detectors correctly today. In `_arm_sign_watchdogs()`, collapsing

    inv.sign_wd.arm(self.sign_cfg if one else self.unit_sign_cfg, ...)

to `arm(self.sign_cfg, ...)` throws the re-derived 250 W / 85 s per-unit pair
away and arms every unit with SAFETY-02's meter-facing 300 W / 180 s - and left
ALL 19 FILES GREEN. Reproduced here before fixing anything: fresh per-mutation
tree, no __pycache__, mounted :ro, graded through tools/mutation_run.sh; -31 B;
19 pass, 0 fail.

WHY NOTHING CAUGHT IT. `grep -rn "sign_wd.cfg" test_*.py` found exactly ONE
threshold assertion, part 7's N=1 arm at (300.0, 1.0) - which the mutation
PRESERVES. Nothing at a roster of two read `inv.sign_wd.cfg` at all. The ledger
mutates the VALUES in SIGN_OPTION_DEFAULTS (M10 250->300, M11 325->180, both
correctly red through the config pins) and never the WIRING that delivers them.
Part 3's behavioural checks cannot close the gap either, and the comment now
says why: B is reversed at ~2000 W with short holds, so it trips under EITHER
pair, and a fault big enough and long enough to trip under both thresholds is
evidence about neither.

THE FIX - test_watchdog.py part 3, on the real two-inverter Controller. Every
`inv.sign_wd.cfg` equals the per-unit pair, `site_sign_wd.cfg` equals the site
pair, and each detector's `against` is its own instrument. Graded against
LITERALS, because `== self.unit_sign_cfg` cannot tell "the per-unit pair" from
"whatever this Controller was handed". Both pairs are printed.

⚠️ AND THE FIXTURE HAD TO CHANGE FOR THE PIN TO MEAN ANYTHING - the recursion
worth naming, because it is the same defect class as the one being closed.
`_sign_site` set `sign_disagree_s`, `unit_sign_disagree_s` AND
`site_sign_disagree_s` all to 1 s, with two of the three magnitude gates at
300 W. A bare equality there discriminates on `min_w` alone: a mis-wiring that
delivered the right magnitude with the WRONG HOLD compares EQUAL to the pair it
was supposed to have. A check comparing two things that happen to be equal
cannot see the difference it names (MUTATION.md's third failure mode). The
three pairs are now pairwise distinct IN BOTH COORDINATES - 250 W / 1 s per
unit, 320 W / 2 s site, 300 W / 3 s shipped - a PRECONDITION asserts that
distinctness so a later edit collapsing them goes red rather than quietly
vacuous, and a second PRECONDITION asserts the literals are the pairs this
Controller actually holds.

VERIFIED BY BREAKING IT. Three mutations, each on its own freshly copied tree
with no __pycache__, mounted :ro, through tools/mutation_run.sh:

  M14  arm() handed self.sign_cfg at every roster        -31 B  RED (was the
       survivor; the AC 5 WIRING check names the wiring)
  M15  right min_w, SHIPPED hold - hold-only mis-wire    +78 B  RED, same pin
  M16  right min_w, SITE hold - hold-only, and it still
       trips inside the drive                            +83 B  RED, and the
       ONLY red in test_watchdog.py

M16 is the one that says the hold half of the equality bites on its own.
Unmutated tree: 19 pass, 0 fail, purged and fingerprinted.

Ledger rows M14-M16 and the write-up in DECISIONS/SAFETY-30-per-unit-sign.md
section 5; a CHANGELOG bullet.

NOT IN THIS PR, so it gets a card rather than a quiet fix: a stuck per-unit
power sensor would false-trip the new per-unit check at N>=2. Already-merged
SAFETY-31 has the identical exposure on the same fixture. Pre-existing N>=2
class, unreachable at the deployed roster of one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
2026-09-04 11:13:13 +02:00

GoodWe RS485 Controller — Home Assistant add-on repository

Replaces a GoodWe battery inverter's vendor controller with a local one: holds net grid exchange at zero by emulating the inverter's smart meter over RS485, and runs the monthly battery maintenance cycle the vendor box was doing.

repository.yaml            add-on repository metadata
goodwe_controller/         the add-on
  config.yaml              manifest + options schema (the per-site config form)
  app/                     the controller
    control.py             the control law — pure functions, no I/O
    maintenance.py         the monthly cycle state machine
    hass.py                Supervisor/Core API access
    store.py               persistent state in /data
    mqtt.py                optional status entities
    web.py                 ingress UI
    main.py                orchestration, heartbeat, failsafe behaviour
  test_control.py          runnable checks — no framework needed
  test_maintenance.py      runnable checks — walks a full cycle in fake time
  DOCS.md                  the add-on's documentation tab
  MUTATION.md              how to run a mutation so the result means something
  tools/mutation_run.sh    the mutation harness - purges bytecode, then grades
firmware/goodwe-master.yaml  ESPHome config for the T-CAN485
estop/rs485_log.py           optional RS485 e-stop / bus witness
docs/GoodWe-RS485-Field-Guide.pdf  the guide techs carry (10pp, A4)
docs/build_guide.py          its single source - rebuilds the HTML and PDF
FIELD-GUIDE.md             how to edit and rebuild the guide

Picking this up after a break? Read HANDOVER.md first — current state, what is known broken, and what to do next.

Install

Settings → Add-ons → Add-on store → ⋮ → Repositories → add

https://gittea.kammenstraatha.duckdns.org/admin/goodwe-addon

then install GoodWe RS485 Controller.

⚠️ The repository must be PUBLIC for this to work. Home Assistant clones it anonymously; against a private repo the store shows nothing and gives no useful error. If it must stay private, install locally instead: copy goodwe_controller/ into the machine's /addons/ folder, then ha store reload — it appears as a Local add-on.

⚠️ Bump version: in goodwe_controller/config.yaml for every change. Supervisor keys the built image by that version, so without a bump it silently reuses the old image and your fix appears not to work — on your bench and on every client's machine.

Requires Home Assistant OS or Supervised. Add-ons cannot be installed on HA Container or Core.

Read this first

The inverter holds its last command forever. It has no meter-timeout of its own — a controller that dies mid-command leaves the battery running until a human intervenes. Measured on real hardware: 5 kW of discharge held for 113 seconds after a controller went silent.

Three layers exist because of that, and only the third covers the Home Assistant machine itself dying:

  1. ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
  2. Wind-down before firmware updates — 0 W written before the update starts.
  3. RS485 e-stop (optional) — writes 0 W after 30 s of total bus silence.

Sites sold without the e-stop must have the acknowledgement in FIELD-GUIDE.md §10 signed.

Development

The control law and the maintenance machine are pure Python with no Home Assistant imports, so they run anywhere:

cd goodwe_controller
python3 test_control.py
python3 test_maintenance.py

Both must pass before shipping any change. To prove a check bites - the way almost every claim in this repository was established - mutate the module and run tools/mutation_run.sh, which clears __pycache__ first. It is not optional: a same-size edit reverted inside one second leaves CPython reusing the old bytecode, and the run grades code that is not there. goodwe_controller/MUTATION.md has the mechanism, the measurement, and what the flags do not do. They are not unit-test theatre — each assertion corresponds to a rule whose absence produced an observed failure on real hardware, and the comments in control.py say which.

Compatibility

Check the serial number, not the model name. Characters 6-8 of the serial are the platform tag:

tag platform verdict
ESU EMU ESA BPS BPU EMJ IJL 105 — ES/EM/BP, AA55-era meter bus supported
SPB SPN 745 — SBP G2 (GW…-SBP-20) no
ESN ESC 745 — ES G2 (GW…-ES-20) no
ETU EHU BTU … 205/745/753 — ET/EH/BT hybrids no
SDT DST MSU NSU … PV-only inverters — no battery to control no

A "-20" or "G2" suffix means a different platform with a different meter protocol. The tags come from the goodwe library's PLATFORM_105_MODELS, which is also what Home Assistant's own integration uses to pick a protocol.

  • GoodWe ES / BP family inverters (AA55 / RS485 meter-bus generation)
  • The protocol is reverse-engineered. There is no vendor contract, and a firmware change on GoodWe's side could break every installation at once. Say so when you sell it.
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