glenn schrooyenandClaude Opus 5
186e13ceca
ARB-03 left `allocate()` as a documented seam that passed through at N<=1 and
DECLINED at N>=2, with the reasoning recorded at the line: the obvious
placeholder - hand the site target to each inverter - IS the ARCH-01 fault, and
"a placeholder that cannot be told apart from the real thing by any guard we
have is worse than no placeholder". This fills the seam.
WHY A BROADCAST IS A FAULT AND NOT AN INEFFICIENCY. The control primitive is
meter emulation: the master reports a FABRICATED grid reading and the inverter
regulates itself to it, so one number means "the battery moves X W" to this
add-on and "the grid is at X W" to the inverter - an identity that holds only at
N=1. Hand two inverters the same target and each supplies it IN FULL, so the
loop gain at the meter becomes N times the per-unit gain. Reproduced on
admin/goodwe's two-master rig against this tree: -400 W export overshoot at
gain 0.6, and at gain 1.0 - which config.yaml accepts as its documented maximum
- a permanent 4000 W peak-to-peak limit cycle, commands alternating
1000/2000/1000/0 W, with NOT ONE GUARD FIRING. The sign watchdog is evaluated on
every cycle and never trips, because the disagreement flips on alternate ticks
and never holds its 180 s window.
WHAT WAS BUILT. `app/allocator.py`, host-side and strictly above the driver
seam. It consumes intervals and a number and nothing else - no claims, no
priorities, and no measurement, because an allocator that read P1 would be a
SECOND integrator on the site measurement.
* ENVELOPE CLAMP, from ARB-03 stage 1's `UnitBounds`, read PER TICK. `plan()`
is a pure function and the module holds no state, so there is nowhere for a
construction-time envelope to be cached.
* WATER-FILL by weight, with the surplus of a full unit moving to the others.
Weights express PREFERENCE, envelopes express PERMISSION: a zero weight is
honoured while another unit has headroom and overridden when it does not,
because the SUM is the safety property and stranding capacity behind a
comfort choice manufactures a standing error at the meter.
* LARGEST-REMAINDER ROUNDING. The target is rounded ONCE, at the top; every
sum below that line is integer arithmetic, so it cannot drift. Measured: a
per-unit round() drifts -125 W over 50 000 ticks at three inverters.
* THE ALLOCATION RECORD, with `unmet_w`, `dropped` and a per-unit reason.
`ok` is one boolean for SAFETY-28 to gate on, and `unmet_w` is deliberately
NOT fused into it - a saturated inverter must not park the whole site.
THE STABILITY PROPERTY IS STRUCTURAL. With sum(a_i) = 1 the gain at the meter is
sum(a_i * g_i), a convex combination of the per-unit gains, so it lies in
[min g_i, max g_i] FOR ANY SPLIT. That is what makes the weights a comfort
choice rather than a tuning parameter, and it is why a bad split cannot
destabilise the site. Graded directly, and measured end to end: 90/10, 50/50 and
100/0 give a bit-identical aggregate trace at the meter, and a gain sweep to 1.0
at every split has a flat tail at all 84 combinations.
THE TWO REFUSALS main.py NOW MAKES, AND WHY THERE ARE TWO. `allocated=False` no
longer means "no allocator"; it means no safe split EXISTS - a mis-routed claim,
an empty envelope set, or a split that could only be made by commanding one pack
to charge while another discharges. Separately, and this guard is the price of
making allocate() succeed rather than something inherited, main.py refuses to
act on a valid split it cannot DELIVER: there is one `setpoint_entity`, so
writing the site target to the one inverter it can reach would over-command that
inverter by exactly the other's share. Commanding a partial site is a worse
instruction than commanding nothing. DEV-02 gives it the second writer.
scope_violations() IS NOW CONSUMED, AND AS A REFUSAL. ARB-03 left it logging
without changing the resolution. A mis-routed claim means the number about to be
divided may itself be wrong, and dividing a number that may be wrong is worse
than not dividing it - the same answer clause 3 already gives a contradiction.
It is NOT promoted into an envelope: a unit-scoped claim that landed on the site
names no unit, so promoting it would mean guessing one, or applying one
inverter's rating to a sibling that does not have it.
AT N<=1 IT IS A PASS-THROUGH, BYTE-IDENTICAL: the share is the site target, as a
float, unrounded and unclamped. All 17 existing suites replay unedited.
test_peakguard.py part 10h and test_arbiter.py part 7 were RE-AIMED, not
deleted. PR #40's reviewer proved that refusal branch was unreachable and
untested once; removing its trigger without giving it a new one would have
rebuilt the hole. Part 10h now drives three real cycles - a deliverable split, a
dead sibling, and every master stale - and grades all three.
KNOWN AND NOT CLOSED HERE: at a roster of two the loop's `actual_w` is one
inverter's power used as a site measurement, because the add-on binds a single
`inverter_power` sensor. That is the SENSING half of the same N=1 identity this
card removes from the COMMANDING half, and it makes the aggregate trace
split-dependent below gain 1.0. Measured with its counterfactual in test_alloc.py
part 8 and tools/alloc_sim.py --splits. It belongs to DEV-02.
Verified: all 18 suites green in the CI image. 16 mutations run through
tools/mutation_run.sh on a purged tree; 13 red, and the 3 survivors are recorded
in test_alloc.py part 12 with the reason each cannot be caught.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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.