glenn schrooyenandClaude Opus 5 03ef61fa3b SAFETY-48: the slew step ceiling reaches the integrator, and what it bounds is the LEAD
`compute()` freezes the integrator with an asymmetric rule and the comment
beside it states the requirement outright - "the requirement is that the
INTEGRATOR stop accumulating, not only the command" - but `frozen` is computed
from ONE signal, `abs(prev_w - actual_w) > saturation_w`, and slew-limiting
never enters it. The integrator moves `gain * error` a cycle and the command
moves at most `slew_w`, so the integrator outruns the command whenever
`|error| > slew_w / gain`: 667 W at the live shape, against a measured median
grid error of 1114 W at the onset of a recorded episode. SAFETY-39's retune
made it MORE frequent, not less - a smaller step is a lower threshold.

⚠️ THE FORM THE CARD ASKED FOR RAISES THE BILLED QUANTITY, WHICH IS WHY IT IS
NOT WHAT SHIPPED. Reusing the asymmetric freeze on a carried slew flag was
built from release/1.0's own source and measured over 16.00 days / 256 252
meter instants of the live install's recorder: export 39.61 -> 34.43 kWh, and
the worst quarter-hour average OFFTAKE 3739 -> 3935 W with the mean quarter
+2.73 W, in five of six plant and tuning variants. A frozen integrator stops at
`prev + gain*error`, which undershoots by (1 - gain); for an export that is
free and for an import it is offtake, for as long as the ramp lasts. The card
said "do not invent a second rule"; the measurement says to, and both sentences
are recorded.

WHAT SHIPS BOUNDS THE LEAD AT ONE SLEW STEP, inside the branch where the slew
actually bound. Same 16 days, same ticks, same disturbance, same plant, same
seed: export 39.61 -> 34.07 kWh, wasted throughput 4.67 -> 3.19 kWh, battery
sign reversals 2992 -> 2770, median recovery 232 -> 199 s, p99 849 -> 850 s,
max 901 -> 898 s, unrecovered 53 -> 31, worst |i_w - prev_w| 9200 -> 800 W -
and the worst 15-minute average offtake 3739 -> 3434 W, i.e. the billed
quantity IMPROVES. `i_w = slewed` (a cap of zero) is better again at 32.02 kWh
and is refused: it is the velocity form this module's docstring says `i_w=None`
collapses to.

TWO COMMITTED NUMBERS MOVED, DELIBERATELY, WITH THE REASON BESIDE THEM.
SAFETY-13's released command settles at -800 W and -1200 W where release/1.0
settled at -1190 W and -2390 W, because there is less wound integrator to
settle onto; AC 4's property - it stops at the frozen integrator, not the rail
- is what is asserted and the second is now graded against `i_w` rather than a
literal. And SAFETY-39's "the slew does not own the over-absorption" is now
FALSE - INVERTED, on the independent first-order plant test_control.py writes
itself: 1005/1109/1285/1330 W rising with a slower slew becomes 729/550/424/326
falling. Two plant models that share nothing agree on the sign.

Evidence: `tools/replay_recorded_loop.py` plus the read-only capture it made
(scenarios/loop-2026-09-02_2026-09-17). The "before" law is the shipped file
with the block removed by a named substitution - never a transcription - and a
missing anchor is a REFUSAL carrying "NOTHING HAS BEEN MEASURED". The
instrument prints its own fidelity first: it reproduces 39.6 kWh of export
where the install exported 29.4, i.e. it is ~35 % pessimistic about the loop's
tracking, so only the delta is claimed.

30/30 suites green, including test_control.py's exhaustive i_w=None
equivalence sweep against the transcribed release/1.0 law, untouched: the cap
moves `i_w` and not `target`, and that sweep compares (target_w, sat_count,
frozen, reason).

Six law mutations, one instrument battery. L4 - the cap applied
unconditionally, -92 B - was a SURVIVOR of all thirty files: it is
bit-identical on the shipped configuration (0 of 256 246 ticks) and separable
on 2050 of 257 400 swept states, all at `integrator_max_w` above `max_w`, which
part 4 now drives. L5 and L6 are ZERO BYTES.

AND TWO COMMENTS IN THIS CARD WERE INVENTED AND ARE CORRECTED IN PLACE. The
one-sided spelling was justified by a two-sided form that would "drag a
trailing integrator" - it does not, and the two agree on 205 920 of 205 920
swept states; and a "118 of 256 252 ticks" figure had been measured against a
different pair. MUTATION.md gains habits 21 and 22 for both shapes.

NOT DEPLOYED, NOT VERSIONED. The live install still runs release/1.0's law.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
2026-09-19 02:36:28 +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 — routes only, status and configuration
    config_page.py         the configuration page's markup, style and script
    configui.py            its field model, built from the Supervisor's own
                           schema + translations — owns no key, label or rule
    selfconfig.py          reading and writing this add-on's own options,
                           with the validate-first / compare-and-swap gate
    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
  tools/supervisor_selfapi_probe.py  what the Supervisor really permits and
                           returns, run against its own release image
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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