`app/main.py:1598`'s `site_standing = float(sum(standing.values()))` is the
first argument of SAFETY-30's latching, site-stopping sign detector AND the
`commanded_w` handed to SAFETY-18's `looks_frozen()`. It was pinned by nothing.
Coverage only: not one byte of `app/` moves - the shipped `sum` is correct.
WHY THE SUITE COULD NOT SEE IT. `_sign_site`, the only N>=2 site fixture in the
repository, runs shares of about -2500 W EACH - every one individually over its
320 W gate - so sum, mean and max(key=abs) all agree on it. Its values happen to
be equal, and a check comparing two things that happen to be equal cannot see
the difference it names. MUTATION.md habit 4, ninth instance, inside the site
half of the card that names the rule in its own text. At N=1 it is arithmetic
rather than a fixture defect: sum == mean == max == the one share, identically.
THE FIXTURE (test_watchdog.py part 9). Two SIMULATED units rated 220 W and
280 W, both obeying exactly, inverted gain, house importing 2000 W: the site
commands -500 W against a +2500 W meter and NO SINGLE SHARE clears the shipped
300 W gate. Four candidate reductions, four distinct answers, one over the gate
- sum -500, mean -250, max(key=abs) -280, [0] -220 - asserted as a precondition.
The asymmetry is load-bearing, and the smaller unit is first so [0] stays
distinct from max(key=abs). Gate shipped; only the hold is shortened.
BOTH CONSUMERS. 9b drives the same discrimination at SAFETY-18's threshold: the
site rail is 0.95 x 500 = 475 W, so the sum rails it while 250, 280 and 220 do
not. Shipped: BLIND_FROZEN, floor 0 W. Under both surviving mutations: not blind
at all, no floor filed - the battery may keep importing through a quarter whose
billed average is unobservable. The open quarter is backfilled with the stuck
reading so the mutant cannot reach the same action by the coverage route and
mask the difference. 9c asserts the N=1 identity on a real one-inverter tree.
SAFETY-32 already closes `list(standing.values())[0]` structurally and this card
does not claim it. Its disclosed blind spot - semantics are invisible to a shape
pin, permanently - is why the mean and max(key=abs) needed a behavioural set.
AND THE SEARCH FOR THE NEXT SURVIVOR FOUND ONE. `float(self.target)` - the
arbiter's site target instead of the sum of what stands on the wire - is -11 B
and survives all 20 files on untouched release/1.0 @ f72c48d, because every
fixture that existed was built where the two are the same number. They separate
when a device's reported range is narrower than its max_w: the `device` claim is
filed per actuator and never bounds the site target. Closed here by a
counterfactual that asks for -500 W while -250 W stands.
10 mutations of that one line, each on a fresh full-repo copy mounted :ro,
purged by tools/mutation_run.sh, the edit re-read from disk and the byte delta
printed. Ledger and honest gaps in DECISIONS/SAFETY-38-site-standing-pin.md.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
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:
- ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
- Wind-down before firmware updates — 0 W written before the update starts.
- 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.