Claude
b68f288fef
check_output_clamp() sits one line below `await self.write_setpoint(self.target)` in cycle(), and moving it above the write left test_clamp.py, test_freeze.py and test_loop.py ALL GREEN. Measured on the move itself before this commit; measured again after, where test_clamp.py part 6 goes red and the other two are still green - the gap was real and it was only ever in this file. WHAT IS ACTUALLY LOST. The guard has two evidence sources. `self.loop_clamped` is set from the Decision well above the write and survives the move, and on the 10.3 runaway replay it is the source of every engagement the alarm reports (0 write-path engagements against 2 loop-side ones) - which is exactly what makes the move nearly invisible. `self.clamp_last` is assigned by write_setpoint() and by nothing else, is None until it has run, and is what `engaged_write` reads at main.py:856. Moved above the write, that consumer goes quietly false and a DEVICE-bound clamp - max_w above the inverter's own rating, SAFETY-20's install - is reported by nothing. A guard whose second evidence source can be silently disconnected is one refactor from being half a guard. WHAT THE CHECK PINS, AND WHAT IT DELIBERATELY DOES NOT. Not the position: the comment at that line warns against tidying SAFETY-03's ordering and SAFETY-18's into one rule, and a check a rename breaks is worse than none. It pins the CONSEQUENCE - what `self.clamp_last` held each time the guard consulted the watchdog - using a spy subclassed from the shipped ClampWatchdog over a slew-limited ramp where every cycle's command is a different number, so "this cycle's evidence" and "last cycle's" are distinguishable at all. The spy hooks `clamp_wd.note()`, the consumer, rather than the guard's name: that is what keeps a rename legitimate. The same assertions are re-run through a controller whose guard is renamed and whose write lives in a helper, and were verified against main.py itself - renaming the method throughout AND moving both calls into a new `_emit_and_guard()` helper keeps part 6 green; swapping the two calls turns it red on a line that names clamp_last. WHY AC 3 NEEDED A NEW STIMULUS, AND WHY IT IS NOT DRIVEN THROUGH cycle(). Through the real cycle() the write-path half cannot engage: the arbiter files the device range and max_w as P_SAFETY LIMIT claims, so resolution.target_w is already inside both bounds before write_setpoint() re-applies them. That duplication is deliberate defence in depth; part 6 now MEASURES the zero engagements rather than leaving it as a claim in a comment, and then drives the write path directly at max_w 5000 against a +-2500 W device - the wire carries 2500 W, every loop-side flag stays clean, and the alarm fires on clamp_last alone. With the two calls swapped the same stimulus clamps the same value and the alarm is silent, which is the ticket in one pair of runs. main.py gains one comment sentence naming the check, mirroring the one SAFETY-18's block already carries for test_freeze.py part 5. No behaviour changes. Full suite: 17/17 green in goodwe-addon-ci. 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.