SAFETY-135 round 2: the first guard stop in a period may restart once; tests and docs

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bdqr7PiaHcBnzPituu2yTC

goodwe_controller/DECISIONS/SAFETY-128-late-readings.md

@@ -71,7 +71,8 @@ The fits run all the time; the pull request has the counts.
 **What it costs.**
 - Found 36-68 s after a lag starts at 1-2 s meters; at a 5 s meter 30 s late
   is found within 100 s after it starts (88 s measured) (the loop first moves 100 W after 60 s,
-  SAFETY-129) with the export above -200 W, and 10 s late is not found. Until
+  SAFETY-129) with the export above -200 W, and 10 s late is not found (SAFETY-136 calms
+  the loop at a slow meter instead). Until
   then control is as before. In a quiet house the "readings late" row stays
   about 2 minutes longer after the lag ends (126 s against 32 s on base); no
   harm measured, and it clears as early as on base when the load changes.

goodwe_controller/DECISIONS/SAFETY-135-young-period.md

@@ -0,0 +1,116 @@
+# SAFETY-135 - one guard stop does not cost the night charge the whole period
+
+**Status: for review, round 2.** Code: `Controller._mode_roles()` and
+`Controller._give_falling()` (`app/ctl_trade.py`), `modetrade.decide(wait=)`,
+`RESTART_S`, `YOUNG_S`, `GAVE_S`, `WAIT_WORDS` (`app/modetrade.py`). Tests:
+`test_safety135.py`. Battery modes only. No option, no change to the peak
+guard.
+
+**Problem.** A grid charge the peak guard stops stays off to the period's end
+(the OPT-11 latch). Three cases seen on TEST-23:
+- *A spike at a period's start* (UX-77 I-1, x10): a 1-3 s spike, or a charge
+  still at full power from the end of the last period, makes the guard project
+  4.3-6.6 kW and cut the charge. The cut is right, but one 2 s spike cost 15
+  minutes of charge, about 0.16 kWh per trip on the rig.
+- *A start at the tariff edge* (sim, 5 s meter): a give ends at 01:00 and the
+  cheap run starts. The battery reading drops at once, the meter a few
+  seconds later. In between, grid + batteries reads the house too low, the
+  room too big: the charge starts and the guard cuts it within seconds.
+- *An oven cycling under a cheap-hours charge* (SAFETY-136 rig run C/s5b, x1):
+  the charge started at 01:00:32 in an oven pause and the guard cut it at
+  01:01:31 when the oven came back on (5.3 kW projected). The cut is right,
+  but the charge stayed off to 01:15.
+
+**Decision.**
+1. *The first guard stop in a period does not latch.* A charge the peak guard
+   stops (or a measured headroom stops in the period's first `YOUNG_S` = 60 s)
+   may start again `RESTART_S` = 60 s after that stop,
+   under the normal start rule (guard clear, headroom over `START_W`), but not
+   in the period's last 60 s: there the room is the deficit times 900/s left,
+   and a restart overshot by 15 W in the owner-shape night (N=2, 01:00). A
+   second stop latches to the period's end, so there is at most one restart
+   per period and the OPT-11 flip guard keeps its job. A measured headroom
+   stop later in the period latches at once, and an unmeasured headroom
+   (OPT-15) on its second stop, as before. Why only guard stops later on: all
+   three rig cases are guard stops, while a headroom that falls to 0 W mid
+   period is the slow loss of room the OPT-11 latch was made for (the
+   2026-09-09 flips), so freeing it buys no case and risks that flip.
+   Three existing checks pinned "one start per period" and move with this:
+   `test_modes_p3.py` (a house swinging 2.0/3.9 kW each minute: now at most
+   two starts per period), `test_price_run_fixes.py` 1c (a 1-minute 3.7 kW
+   load: one restart after 60 s), and the `n1_ch` digest in
+   `test_modes_p4.py` (only the waiting reason word moved, "(peak)" for
+   "(headroom)"; with this card off it is OPT-15's pin again).
+2. *No start while a give is still falling.* In a period's first `YOUNG_S`,
+   while the batteries give over `START_W` less than they did in the
+   last `GAVE_S` = 15 s, no charge starts: the meter may not show that drop
+   yet. A smaller drop does not hold the start.
+
+The guard is not touched (claim, floor, projection), so a real over-aim load
+is cut on the same cycle as before, and a running charge is never held. While
+a start waits, the status row says "grid charge paused, it tries again in a
+minute" or "grid charge waits for the meter to catch up".
+
+**Options weighed.**
+- *Round 1: only a stop in the first 60 s does not latch.* Missed the rig
+  oven case, cut at 91 s (review M-1).
+- *Re-evaluation each cycle with no latch*: brings back the 13 flips in 4
+  minutes the latch was made for (2026-09-09 replay).
+- *Restart at once after the first stop*: two flips in 20 s with spikes at
+  0/20 s (`test_safety135.py` part 5 fails on it).
+- *No start in a young period within 60 s of a give or a guard action*:
+  0.018 kWh (N=1) and 0.003 kWh (N=2) less than base on the owner night.
+- *Cutting the young room by the recent give*: double-counts once the meter
+  catches up and flapped on a 1 s meter where base did not.
+- *A hysteresis band*: the edge error is the readings' age, not a small room.
+
+**Numbers** (`scratch/SAFETY-135/dev/s135_sim.py`, real `cycle()`, TEST-23-like
+lag, 1 s cycle, two 2.5 kW batteries unless said, cap 3 500 W, aim 3 450 W;
+the sim's grid average per period):
+
+| Scenario | Base: paused s, kWh, flaps, top period | Head |
+|---|---|---|
+| (a) 4 s spike at 01:30 and 01:45, house 2.8 kW | 1 197 s, 0.330 kWh, 1, 3 458 W | 139 s, 0.537 kWh, 0, 3 458 W |
+| (b) 01:00 edge after a give, 5 s meter, house 3.0 kW | 882 s, 0.006 kWh, 1, 3 009 W | 21 s, 0.119 kWh, 0, 3 464 W |
+| (b) the same, house 2.4 kW | 0 s, 0.266 kWh, 0, 3 461 W | 11 s, 0.266 kWh, 0, 3 461 W |
+| Rig s5b (5 kW + 4.6 kW, oven), 1 s / 5 s meter | 838 / 886 s, 0.054 / 0.035 kWh, 2 224 / 2 123 W | 793 / 793 s, 0.075 / 0.084 kWh, 2 299 / 2 286 W |
+| (c) +4 kW for 5 min from 01:30:20 | cut 01:30:22, 0.387 kWh | cut 01:30:22, 0.492 kWh |
+| Owner-shape night, N=1 / N=2 | 5.510 / 6.048 kWh, top 3 454 / 3 453 W | 5.510 / 6.169 kWh, 3 454 / 3 453 W |
+| Owner-shape day, N=1 / N=2 | top 331 / 145 W | the same |
+
+In s5b the restart at 01:02:32 is cut again by the oven at 01:03:17 and then
+latches: one restart, as designed. A +4 kW load from second 30, 57, 59, 60 or
+61 (N=1 and N=2) is cut on the same cycle as base, the charge restarts only
+after the load ends, and the period lands at 3 450.0 W (base 3 037-3 350 W).
+The add-on's own period averages in `test_safety135.py` are at or under the
+aim + 2 W in every part.
+
+**Sensitivity** (one constant moved, the others as shipped; head):
+
+| Constant | Spike (a): paused s, kWh | Edge (b) 5 s meter 3.0 kW: paused s, flaps | Rig s5b 1 s: kWh, period W | Owner night N=2: kWh, top W |
+|---|---|---|---|---|
+| `RESTART_S` 30 | 79, 0.541 | 21, 0 | 0.082, 2 321 | 6.206, **3 459** |
+| `RESTART_S` 60 (shipped) | 139, 0.537 | 21, 0 | 0.075, 2 299 | 6.169, 3 453 |
+| `RESTART_S` 90 | 199, 0.532 | 21, 0 | 0.061, 2 250 | 6.169, 3 453 |
+| `RESTART_S` 120 | 259, 0.528 | 21, 0 | 0.085, 2 338 | 6.169, 3 453 |
+| `GAVE_S` 5 | - | 75, **1** | 0.075, 2 299 | 6.170, 3 453 |
+| `GAVE_S` 10 | - | 15, 0 | 0.075, 2 299 | 6.169, 3 453 |
+| `GAVE_S` 15 (shipped) | - | 21, 0 | 0.075, 2 299 | 6.169, 3 453 |
+| `GAVE_S` 30 | - | 35, 0 | 0.073, 2 290 | 6.168, 3 453 |
+| `YOUNG_S` 30 / 90 | - | 21, 0 | 0.075, 2 299 | 6.169, 3 453 |
+
+`RESTART_S` 30 restarts the owner night in a period's last 30 s and lands
+9 W over base's top period; 60 is the shortest value without that. In s5b
+the value only moves where the restart meets the oven cycle. `GAVE_S` 5 s is
+shorter than a 5 s meter's age and flaps again; 10-30 s only move the wait.
+`YOUNG_S` does not move these runs: the give falls in the first seconds.
+
+On the synthetic night where the house alone is 950 W over the aim (N=1,
+heat pump 4.4 kW), head's top period is 4 403 W against base's 4 401 W: a
+charge restarted in the period before runs into the heat pump's start (the
+carry-over below). Base charges 1.142 kWh there, head 1.560 kWh.
+
+**Not changed.** With battery modes off, `arbitrage.decide()` has no period
+latch and sizes the charge to the headroom each cycle (SAFETY-45). A charge at
+full power in a period's last seconds still runs into the next period (the
+charge side of SAFETY-124); with rule 1 that costs 60 s, not the period.

goodwe_controller/DECISIONS/SAFETY-136-slow-meter-settle.md

@@ -0,0 +1,81 @@
+# SAFETY-136 - a slow meter gets a gentler loop until the last move shows
+
+**Status: for review.** Code: `app/settle.py`, a call in `Controller.cycle()`
+(`app/ctl_cycle.py`). Tests: `test_safety136.py`. No option, no text change.
+
+**Problem.** On a 5 s meter, Home Assistant readings 10-15 s late are not
+found (SAFETY-129): they look like a slow battery (R2-1), and a hold does not
+help (a perfect one cut the export of the oven by 7 %, SAFETY-129 review).
+With moving loads the loop answers the same stale error at each cycle and
+overshoots: an oven, a kettle and hob, the owner's day or a step export 3-10
+times what they do with no lag. The fix is a calmer loop, not a detector.
+
+**Decision.** After a move of 150 W or more, a loop on a slow meter runs at half
+its gain until the meter has fallen by half of that move, or for 2 cycles.
+Slow is judged from the readings that arrive: the usual gap
+between them, over the last 60 s and at least 5 readings, is over 3.75 s (the
+limit of SAFETY-128's fast meter fit). It counts arrivals, not changes of
+value: on the recorded day at 1-2 s the value-based test (`MeterFit.slow()`)
+called 24 % of the cycles slow, because the recorded house repeats a value
+for 5 s or more, and the commands then differed from base. So there is no
+option. At a meter with a usual gap of 3.75 s or less (1-3 s) it is false, the tuning is never touched and the
+commands are those of the tree before. A meter that Home Assistant passes on
+only when its value changes looks as slow as its changes are far apart, as it
+does to SAFETY-128's fits: a 1-2 s meter with a value that holds for 5 s or
+more is then treated as slow, and the loop is gentler for it (the cost below).
+With no lag the meter shows a move at the next reading, so the wait ends at
+once.
+
+**Candidates** (SAFETY-129 sim, real `cycle()`, 5 s meter, sum over oven,
+kettle and hob, owner shape over the oven and over the heat pump, step down,
+step up, flat; export Wh, lag 0 / 10 s / 15 s; base 64 / 340 / 363):
+
+| Candidate, only at a slow meter | 0 s | 10 s | 15 s | Import Wh, 0 / 10 / 15 s |
+|---|---|---|---|---|
+| gain 0.4 | 97 | 201 | 299 | 97 / 224 / 301 |
+| gain 0.3 | 128 | 185 | 322 | 132 / 232 / 293 |
+| step limit 500 W | 118 | 285 | 293 | 110 / 325 / 324 |
+| cut fast, raise slowly (0.6 / 0.3) | 55 | 140 | 226 | 140 / 332 / 345 |
+| ignore 1 cycle after a move | 93 | 216 | 325 | 90 / 240 / 291 |
+| ignore 2 cycles after a move, unless the meter showed half | 69 | 206 | 277 | 62 / 240 / 354 |
+| **half gain for 2 cycles after a move, unless the meter showed half** | **67** | **189** | **296** | **62 / 223 / 288** |
+
+A lower gain for good, a step limit and a fixed ignore all make a 5 s meter
+with no lag worse (export +30-110 Wh, quarter peak up to 150 W): that is the
+common case. Cutting fast and raising slowly moves export to import and peak.
+Waiting only while the last move has not shown costs nothing with no lag.
+Ignoring the meter (the 2-cycle line) was worse than half gain where the plant
+is slow, not the readings late: a 12 s dead time with one inverter went from
+250 to 841 Wh import and a quarter peak of 206 to 1 509 W, so the loop keeps
+following at half gain.
+
+**What it gives** (5 s meter; the pull request and the report have each
+scenario). Export summed over the seven houses: 10 s late 340 -> 189 Wh
+(-44 %, import 363 -> 223), 15 s late 363 -> 296 Wh (-19 %, import 281 ->
+288), together -31 %. At 15 s the oven and the owner's oven are not better
+(92 / 39 Wh against 91 / 37), the kettle and the steps are. No lag: export
+64.4 -> 66.5 Wh (kettle +2), import and peak the same.
+
+**What it costs.** The loop follows a real step more slowly: half gain for up
+to two cycles after each move of 150 W or more. Of the 136 sim runs (every
+SAFETY-129 review scenario and its 15 harm runs), 56 at 4-10 s meters differ
+from base. Together their export is 10 363 -> 9 559 Wh (-8 %) and import
+8 389 -> 7 835 Wh (-7 %). Only 5 export more than 1 Wh and 14 import more:
+export by at most 11.5 Wh (a 10 s battery lag, +10 %), import by at most
+17 Wh (a 12 s dead time, one inverter, +7 %), and the quarter average by at
+most 35 W, except two import quarters: +73 W (10 s meter, 10 s dead time,
+export -59 Wh) and +40 W (`dead10_p6`, -6 to 34 W, export -68 Wh). Slow
+batteries with a dead time of 8-10 s export 5-39 % less; a 12 s dead time is
+the same. `READINGS_LATE` holds are the same seconds in every run.
+
+**Live, a 1-2 s meter can be judged slow.** Through Home Assistant on change,
+a value that holds for 4-10 s makes a 1 s meter slow. In 20 rig scenarios the
+commands were those of base. On the recorded day (1 s, N=1, 1 day, repeats
+dropped; its values hold about 5 s) it was slow in 33 % of cycles, half gain
+in 83 cycles, 15 422 commands in both trees, 4 016 with another value (at
+most 190 W apart), cost 0.61 EUR in both (review of SAFETY-136).
+
+**Does not change.** Meters of 1-2 s: the same commands in all 63 runs (34
+at 1 s, 29 at 2 s), and the recorded-day digests (see the report). The late
+verdict, the hold and the freeze tests. 15 s late is only partly helped, and
+30 s late is the hold's (SAFETY-129).

goodwe_controller/app/ctl_cycle.py

@@ -734,15 +734,21 @@ class CycleMixin:
             # TEL-10. ⚠️ ONE NAME FOR THE COMMAND THE LOOP WAS MEASURED
             # AGAINST. (DECISIONS/MAIN-orchestration-archive.md)
             loop_prev = self.target
+            # SAFETY-95: a drain's tail is not the loop's to chase.
+            # OPT-15: `loop_grid` is the grid, or the target while a run
+            # edge is held.
+            grid_in = (self._drain_grid_w(_live96) if self._drain_tail
+                       else loop_grid)
+            # SAFETY-136: on a slow meter, a gentler loop until the last move
+            # shows.
+            slow_meter = self.settle.slow()
+            if moved or mode_trade:
+                self.settle.reset()
             decision = compute(
                 prev_w=loop_prev,
-                # SAFETY-95: a drain's tail is not the loop's to chase.
+                grid_w=grid_in,
-                # OPT-15: `loop_grid` is the grid, or the target while a run
-                # edge is held.
-                grid_w=(self._drain_grid_w(_live96) if self._drain_tail
-                        else loop_grid),
                 actual_w=site_batt,
-                tuning=self.tuning,
+                tuning=self.settle.tuning(self.tuning, grid_in, slow_meter),
                 sat_count=self.sat_count,
                 i_w=self.i_w,
                 # SAFETY-52 at one inverter only: with several, OPT-09's pack
@@ -772,6 +778,7 @@ class CycleMixin:
                 self.log_event(f"saturation freeze ({self.target:.0f} W vs "
                                f"{site_batt:.0f} W)",
                                hint=messages.hint("not_keeping_up"))
+            self.settle.moved(grid_in, loop_prev, decision.target_w, slow_meter)
             self.sat_count = decision.sat_count
             self.i_w = decision.i_w
             self.loop_w = decision.target_w
@@ -811,6 +818,7 @@ class CycleMixin:
         else:
             # Stopped or blind: no accumulation may survive the outage.
             self.i_w = 0.0
+            self.settle.reset()
             self.loop_w = None
             self._live_was = frozenset(_live96)
             # TEL-10, and it is the same zero the line above writes rather than

goodwe_controller/app/ctl_inputs.py

@@ -197,6 +197,7 @@ class InputsMixin:
             # correlates 0.998 with battery power and 0.09 with the real meter
             # (a controller would regulate against its own output).
             self.grid = self.p1.net_w
+            self.settle.arrive(now_mono, self.p1.samples)   # SAFETY-136
         else:
             self.grid = await self.hass.number(o.get("meter_entity", ""),
                                                bool(o.get("meter_invert")))

goodwe_controller/app/ctl_trade.py

@@ -2,6 +2,7 @@
 
 Moved unchanged from app/main.py (MAINT-21). DECISIONS/MAIN-orchestration.md."""
 
+import collections
 import dataclasses
 import logging
 from datetime import datetime, timedelta, timezone
@@ -401,6 +402,18 @@ class TradeMixin:
         quarter = int(now.timestamp() // 900)
         was = self.mode_tick is not None and \
             self.mode_tick.action == modetrade.CHARGE
+        # SAFETY-135: the first guard stop in a period (or measured headroom
+        # stop in a young one) does not latch; the charge may start again
+        # RESTART_S after it, but not in the period's last RESTART_S. No
+        # start in a young period while a give falls.
+        # DECISIONS/SAFETY-135-young-period.md
+        st = getattr(self, "_charge_stop", None)
+        paused = (st is not None and st[0] == quarter
+                  and (now.timestamp() - st[1] < modetrade.RESTART_S
+                       or (quarter + 1) * 900 - now.timestamp()
+                       < modetrade.RESTART_S))
+        wait = ("wait" if paused else
+                "settle" if self._give_falling(now) else None)
         self.mode_tick = modetrade.decide(
             runs, now, packs, charge_ok=charge_ok, sell_ok=sell_ok,
             trade_why=trade_why, price_now=price_now,
@@ -408,7 +421,8 @@ class TradeMixin:
             ceiling_pct=ceiling_pct, house_w=house, charging_now=was,
             blocked=self._charge_blocked_q == quarter,
             done_charge=done_c, done_sell=done_s, targets=targets,
-            draining=any(r.phase == DRAIN for r in maint_results or ()))
+            draining=any(r.phase == DRAIN for r in maint_results or ()),
+            wait=wait)
         self._latch_charge(now, runs, targets, packs)
         # A charge the guard or the headroom stopped stays off this period.
         # OPT-15: only a MEASURED stop latches; the first unmeasured headroom
@@ -419,11 +433,38 @@ class TradeMixin:
             gap = why == "headroom" and self.arb_headroom_w is None
             if why == "peak" or (why == "headroom" and not gap) or (
                     gap and self._charge_gap_q == quarter):
-                self._charge_blocked_q = quarter
+                young = now.timestamp() - quarter * 900 < modetrade.YOUNG_S
+                if (why == "peak" or (young and not gap)) and (
+                        st is None or st[0] != quarter):
+                    self._charge_stop = (quarter, now.timestamp())
+                else:
+                    self._charge_blocked_q = quarter
             elif gap:
                 self._charge_gap_q = quarter
         return self.mode_tick
 
+    def _give_falling(self, now) -> bool:
+        """SAFETY-135: True in a young period while the batteries give over
+        START_W less than they did in the last GAVE_S s: the meter may not
+        show that yet, so a charge room read now is too big.
+        DECISIONS/SAFETY-135-young-period.md"""
+        t = now.timestamp()
+        gave = getattr(self, "_gave", None)
+        if gave is None:
+            gave = collections.deque()
+            self._gave = gave
+        if gave and t < gave[-1][0]:
+            gave.clear()                    # the clock stepped back
+        if self.site_batt_w is not None:
+            gave.append((t, max(0.0, float(self.site_batt_w))))
+        while gave and t - gave[0][0] >= modetrade.GAVE_S:
+            gave.popleft()
+        if self.site_batt_w is None or not gave \
+                or t % 900 >= modetrade.YOUNG_S:
+            return False
+        drop = max(w for _t, w in gave) - max(0.0, float(self.site_batt_w))
+        return drop > modetrade.START_W
+
     def _run_mark(self, kind, run, packs, out, extra=None) -> set:
         """The batteries that left run `run` (full, or at the floor); they
         stay out until it ends, so a level edge does not re-arm them.
@@ -475,7 +516,8 @@ class TradeMixin:
                 None, 0.0, "size")
         if size == 0.0 or runs is None:
             reason = ("battery modes: no price run now" if tick.why is None
-                      else f"battery modes: no trade ({tick.why})")
+                      else modetrade.WAIT_WORDS.get(tick.why)
+                      or f"battery modes: no trade ({tick.why})")
             self.arb = arbitrage.ArbitrageDecision(
                 action=None, power_w=None, reason=reason,
                 spread_eur_kwh=None, required_eur_kwh=None,

goodwe_controller/app/main.py

@@ -22,6 +22,7 @@ ctl_inputs, ctl_writes, ctl_trade, ctl_cycle, ctl_alarms, ctl_status and
 ctl_tasks (MAINT-21), the status-row functions in rows."""
 
 import asyncio
+import collections
 import contextlib
 import dataclasses
 import functools
@@ -63,6 +64,7 @@ from .clamp import (
 )
 from . import freshness
 from . import lateness
+from .settle import Settle
 from . import dayview, homeview
 from .daycurve import SolarToday
 from . import handback
@@ -527,6 +529,8 @@ class Controller(InputsMixin, WritesMixin, TradeMixin, CycleMixin, AlarmsMixin,
         self._mode_trade_was = False
         self._charge_blocked_q = None
         self._charge_gap_q = None       # OPT-15: an unmeasured stop's quarter
+        self._charge_stop = None        # SAFETY-135: (quarter, t) first stop
+        self._gave = collections.deque()  # SAFETY-135: (t, W given), GAVE_S
         self._ref_cheap = None
         # OPT-15: a run edge the loop holds at E: (E, step sign, until, the
         # last battery reading).
@@ -741,6 +745,7 @@ class Controller(InputsMixin, WritesMixin, TradeMixin, CycleMixin, AlarmsMixin,
         self._arb_action = None
         self.inputs_bad_since = None
         self.answer = lateness.Answer()           # SAFETY-128
+        self.settle = Settle()                    # SAFETY-136
         self._late_logged = self._late_zero = False
         # SAFETY-03: what the loop's OWN bounds did last cycle, `(engaged,
         # note, over_rating)` (SAFETY-40 splits the last out). Site-level: the

goodwe_controller/app/modetrade.py

@@ -36,6 +36,10 @@ Rules that keep this safe (tests: test_modes_p3.py, test_price_run_fixes.py):
     makes the other batteries stop giving power, so a few watts of charge
     flipping on and off would swing the house between them and the grid
     (measured on the 2026-09-09 replay: 13 flips in 4 minutes at 3.5 kW);
+    SAFETY-135: the first such stop in a period holds the charge RESTART_S
+    only, a second one to the period's end (at most one restart), and in a
+    period's first YOUNG_S s no charge starts while the batteries' give is
+    still falling (`wait`);
   * selling needs selling on for that battery, the sell run, a price >= 0
     now, and the battery above `arbitrage_soc_floor`; it stops there. The
     peak guard never stops a sell (section 9.1: discharge is never capped);
@@ -69,6 +73,18 @@ PRICE_MODES = (LEFTOVER_SOLAR, CHEAP_HOURS)
 # would stop covering the house for less than they give.
 START_W = 500.0
 
+# SAFETY-135: how long the first stop in a period holds the charge, how long
+# a period is young, and how far back a give may not be on the meter yet.
+# DECISIONS/SAFETY-135-young-period.md
+RESTART_S = 60.0
+YOUNG_S = 60.0
+GAVE_S = 15.0
+# SAFETY-135: the plain status words for `wait` (UX-08).
+WAIT_WORDS = {
+    "wait": "battery modes: grid charge paused, it tries again in a minute",
+    "settle": "battery modes: grid charge waits for the meter to catch up",
+}
+
 
 @dataclass(frozen=True)
 class Pack:
@@ -164,7 +180,7 @@ def energy(packs, floor_pct, ceiling_pct, done_charge=(), done_sell=(),
 def decide(runs, now, packs, *, charge_ok, sell_ok, trade_why, price_now,
            headroom_w, floor_pct, ceiling_pct, house_w, charging_now=False,
            blocked=False, done_charge=(), done_sell=(),
-           targets=None, draining=False) -> Tick:
+           targets=None, draining=False, wait=None) -> Tick:
     """This tick's ranges, roles and site ask.
 
     `runs` is the kept `priceruns.RunPlan` or None (no fresh prices).
@@ -177,7 +193,8 @@ def decide(runs, now, packs, *, charge_ok, sell_ok, trade_why, price_now,
     it going); `blocked` that the guard or the headroom stopped a charge in
     this 15-minute period. `targets` is the day plan (`charge_to()`).
     `draining` says a battery drains for its monthly cycle, so none may
-    charge from the grid (why "cycle").
+    charge from the grid (why "cycle"). `wait` ("wait" or "settle", the
+    why) says no charge may start yet (SAFETY-135).
     """
     plan_on = runs is not None and runs.on
     in_cheap = plan_on and runs.cheap.holds(now) and runs.charge_useful()
@@ -198,6 +215,8 @@ def decide(runs, now, packs, *, charge_ok, sell_ok, trade_why, price_now,
             why = trade_why
         elif headroom_w is None or not headroom_w > need:
             why = "headroom"
+        elif wait and not charging_now:
+            why = wait
         else:
             charging = True
     se = sellers(packs, floor_pct, done_sell) if in_sell and not charging \

goodwe_controller/app/settle.py

@@ -0,0 +1,74 @@
+"""SAFETY-136: on a slow meter, follow the meter gently until the last move shows.
+
+A meter whose usual gap between readings is over 3.75 s (a 4-5 s meter), read
+through Home Assistant, can be 10-15 s late. The loop then answers the same error again at each cycle
+and overshoots. After a move of MOVE_W or more the loop therefore runs at
+WAIT_SHARE of its gain until the meter has fallen SHOWN of the move, or for at
+most WAIT_CYCLES cycles. Off for a meter with a usual gap of 3.75 s or less, so those sites run as
+before. DECISIONS/SAFETY-136-slow-meter-settle.md.
+"""
+
+from collections import deque
+from dataclasses import replace
+
+from .lateness import M_FIT_S, M_ROWS
+
+# A meter is slow when its readings come further apart than this (the usual
+# gap, over the last 60 s and at least 5 readings): the fast meter fit's own
+# limit (SAFETY-128), 3.75 s.
+SLOW_GAP_S = M_FIT_S / M_ROWS
+SLOW_ROWS = 5
+# A move this big is waited for (above the house noise of about 80 W).
+MOVE_W = 150.0
+# The meter has shown a move once it fell by this share of it.
+SHOWN = 0.5
+# Meanwhile the loop runs at this share of its gain.
+WAIT_SHARE = 0.5
+# Wait at most this many cycles (10 s at a 5 s meter).
+WAIT_CYCLES = 2
+
+
+class Settle:
+    def __init__(self):
+        self.pend = None          # (meter at the move, the move in W, cycles waited)
+        self._n = None            # readings taken in so far
+        self._at = deque()        # when the last ones arrived, over M_FIT_S
+
+    def arrive(self, now, n):
+        """Each read: `n` is the count of meter readings taken in. A reading
+        counts when it arrives, not when its value changes, so a steady load on
+        a 1 s meter is not a slow meter."""
+        if n != self._n:
+            self._n = n
+            self._at.append(now)
+        while self._at and self._at[0] < now - M_FIT_S:
+            self._at.popleft()
+
+    def slow(self):
+        """The usual gap between readings is over SLOW_GAP_S."""
+        ts = list(self._at)
+        if len(ts) < SLOW_ROWS:
+            return False
+        gaps = sorted(b - a for a, b in zip(ts, ts[1:]))
+        return gaps[len(gaps) // 2] > SLOW_GAP_S
+
+    def reset(self):
+        self.pend = None
+
+    def tuning(self, tuning, grid_w, slow):
+        """The tuning for this cycle: `tuning`, or with the gain cut while the
+        last move has not shown on the meter (`grid_w`)."""
+        p = self.pend
+        if p is None:
+            return tuning
+        g0, move, waited = p
+        if not slow or (g0 - grid_w) / move >= SHOWN or waited >= WAIT_CYCLES:
+            self.pend = None
+            return tuning
+        self.pend = (g0, move, waited + 1)
+        return replace(tuning, gain=tuning.gain * WAIT_SHARE)
+
+    def moved(self, grid_w, prev_w, new_w, slow):
+        """After a cycle: start waiting if the loop moved by MOVE_W or more."""
+        if slow and self.pend is None and abs(new_w - prev_w) >= MOVE_W:
+            self.pend = (float(grid_w), float(new_w - prev_w), 0)

goodwe_controller/test_modes_p3.py

@@ -472,15 +472,36 @@ _sw = [(UTC0.timestamp() + 60 * k, 2000.0 if k % 2 else 3900.0)
 ROWS_W, _, _ = run_day("p3_ch_sell", hours=1.5, house=_sw,
                        soc0={"a": 60.0, "b": 30.0})
 _per_q = {}
+_ev_q = {}          # SAFETY-135: per period, the charge's starts and stops
 for a_, b_ in zip(ROWS_W, ROWS_W[1:]):
-    if a_["action"] != arbitrage.CHARGE and b_["action"] == arbitrage.CHARGE:
+    on_a, on_b = (a_["action"] == arbitrage.CHARGE,
+                  b_["action"] == arbitrage.CHARGE)
+    if on_a != on_b:
+        q = int(b_["now"].timestamp() // 900)
+        _ev_q.setdefault(q, []).append((on_b, b_["now"].timestamp()))
+    if not on_a and on_b:
         q = int(b_["now"].timestamp() // 900)
         _per_q[q] = _per_q.get(q, 0) + 1
+
+
+def _one_restart(ev):
+    """At most one start after a stop in the period, RESTART_S or more after
+    it; a second stop is the last change of the period."""
+    re = [(t0, t1) for (s0, t0), (s1, t1) in zip(ev, ev[1:])
+          if not s0 and s1]
+    stops, late = 0, False
+    for on, _t in ev:
+        stops += 0 if on else 1
+        late = late or (on and stops >= 2)
+    return (len(re) <= 1 and not late
+            and all(t1 - t0 >= modetrade.RESTART_S - 1 for t0, t1 in re))
 print(f"    house swinging 2.0/3.9 kW each minute: charge starts per period "
       f"{sorted(_per_q.values())}")
 check("a charge the peak guard or the headroom stopped stays off for the "
-      "rest of that 15-minute period (at most one start per period)",
+      "rest of that 15-minute period, after at most one restart RESTART_S or "
-      _per_q and max(_per_q.values()) == 1)
+      "more after the first stop; a second stop latches (SAFETY-135)",
+      _per_q and max(_per_q.values()) <= 2
+      and all(_one_restart(ev) for ev in _ev_q.values()))
 
 # At the floor: B starts the sale just above it.
 ROWS_F, _, _ = run_day("p3_ch_sell", start_h=18.75, hours=1.5,

goodwe_controller/test_modes_p4.py

@@ -65,11 +65,16 @@ print("1. no usable forecast: byte-identical to 5a4cdc2 (P3 option A)")
 # OPT-15 head: a charge end now holds the loop at the house's level (F2). With
 # that hold and its reseed switched off they equal 5a4cdc2's again; the others
 # (no charge) never moved.
+# SAFETY-135: n1_ch re-pinned. A first guard stop no longer latches, so while
+# the charge waits its reason reads "(peak)" where the latch said
+# "(headroom)"; no command moves. With SAFETY-135 off it is OPT-15's pin
+# again (checked below).
+N1_CH_OPT15 = "97893a54f8a8e3f36ad24f100973b3ff35766527e7287a6ae30cc1c8941bac02"
 BASE_DIGESTS = {
     "n1_ls":
         "13f11c330263c91625acde7628426ff16dae3a9af99aebeef3051dc5b5a884ea",
     "n1_ch":
-        "97893a54f8a8e3f36ad24f100973b3ff35766527e7287a6ae30cc1c8941bac02",
+        "5d529f516307e4da4dca48714ee891332a2eea5e1b1763f0f1e049cfb0819a0a",
     "n2_sf_ls":
         "9424e1837b805a6a31293a28b8fbad6ba611ea0bfe3240d636d68d62dc5e9f22",
     "n2_ch_ls":
@@ -81,7 +86,7 @@ BASE_DIGESTS = {
     "n1_ls_fc_down":
         "13f11c330263c91625acde7628426ff16dae3a9af99aebeef3051dc5b5a884ea",
     "n1_ch_fc_down":
-        "97893a54f8a8e3f36ad24f100973b3ff35766527e7287a6ae30cc1c8941bac02",
+        "5d529f516307e4da4dca48714ee891332a2eea5e1b1763f0f1e049cfb0819a0a",
     "n2_sf_ls_fc_down":
         "9424e1837b805a6a31293a28b8fbad6ba611ea0bfe3240d636d68d62dc5e9f22",
     "n2_ch_ls_fc_down":
@@ -98,6 +103,38 @@ for k, v in BASE_DIGESTS.items():
     check(f"{k}: pinned digest (5a4cdc2; OPT-15 for the _ch ones)",
           got.get(k) == v)
 check("every scenario is pinned", set(got) == set(BASE_DIGESTS))
+
+
+class _Every:
+    """SAFETY-135 off: a stop period equal to every period, so every guard
+    stop latches as before."""
+
+    def __eq__(self, other):
+        return True
+
+    def __ne__(self, other):
+        return False
+
+
+def _s135_off_digest(scn):
+    from app import main as _m
+    real = _m.Controller.__init__
+
+    def init(self, *a, **k):
+        real(self, *a, **k)
+        self._charge_stop = (_Every(), float("-inf"))
+    young, restart = modetrade.YOUNG_S, modetrade.RESTART_S
+    _m.Controller.__init__ = init
+    modetrade.YOUNG_S = modetrade.RESTART_S = 0.0
+    try:
+        return ident.p3.digest(ident.run(**ident.SCENARIOS[scn])[0])
+    finally:
+        _m.Controller.__init__ = real
+        modetrade.YOUNG_S, modetrade.RESTART_S = young, restart
+
+
+check("n1_ch with SAFETY-135 off is OPT-15's pin: only the reason word moved",
+      _s135_off_digest("n1_ch") == N1_CH_OPT15)
 for k in [k for k in got if k.endswith("_fc_down")]:
     check(f"{k}: a set but unavailable forecast equals no forecast",
           got[k] == got[k[:-len('_fc_down')]])

goodwe_controller/test_price_run_fixes.py

@@ -6,7 +6,8 @@ with the lagged model (`Lag`: command dead time, meter and battery reading
 age, the P1 debounce, 1 s cycles), which reproduces all three on 5a4cdc2.
 
 1. F1: a quarter edge while charging does not stop the charge (the guard
-   projects the quarter `now` is in), and a real guard stop still latches.
+   projects the quarter `now` is in), and a real guard stop still holds it
+   (SAFETY-135: one restart a minute later, then a second stop latches).
    At two inverters SAFETY-91's `next_quarter()` already does that for the
    guard; at one inverter only the rolled projection does.
 2. F2: the export overshoot at a charge end stays within 0.15 x rating in
@@ -252,7 +253,8 @@ check("two inverters: SAFETY-91 already holds the edge (no stop with the old "
       "projection), and rolling it changes no banked quarter",
       not stops(ROWS1O) and banked(C1O, ROWS1O) == banked(C1, ROWS1))
 
-# 1c. A real guard stop still latches, and the 500 W minimum stays.
+# 1c. A real guard stop holds the charge (SAFETY-135: one restart after
+# RESTART_S, a second stop latches), and the 500 W minimum stays.
 # House: 800 W; 3700 W at 02:20-02:21; 3000 W from 02:26 (headroom 450 W
 # in the next quarter); 2850 W from 02:40 (600 W).
 ROWS2, C2 = run(1.9, 0.9, lag=LAG, steps=[
@@ -266,11 +268,24 @@ _after2 = [r for r in ROWS2 if _first and r["now"] > _first["now"]
 print(f"    guard stop at "
       f"{_first['now'].astimezone(L).strftime('%H:%M:%S') if _first else None}"
       f" ({_first['reason'][:40] if _first else ''})")
-check("a mid-quarter 3.7 kW load stops the charge for the peak and it stays "
+# SAFETY-135: the first guard stop in a quarter holds the charge RESTART_S,
-      "off for the rest of that quarter, the house back at 800 W",
+# then it may start once more; a second stop latches to the quarter's end.
+_hold2 = [r for r in _after2
+          if (r["now"] - _first["now"]).total_seconds() < modetrade.RESTART_S]
+_on2 = [b for a, b in zip(_after2, _after2[1:])
+        if a["action"] != arbitrage.CHARGE and b["action"] == arbitrage.CHARGE]
+_off2 = [b for a, b in zip(_after2, _after2[1:])
+         if a["action"] == arbitrage.CHARGE and b["action"] != arbitrage.CHARGE]
+print(f"    after it: {len(_on2)} restart(s), {len(_off2)} more stop(s)")
+check("a mid-quarter 3.7 kW load stops the charge for the peak; it stays off "
+      "for RESTART_S, then starts again at most once that quarter, and a "
+      "second stop holds it off to the quarter's end (SAFETY-135)",
       _first is not None and _first["now"].astimezone(L).minute == 20
       and ("peak" in _first["reason"] or "headroom" in _first["reason"])
-      and _after2 and all(r["action"] is None for r in _after2))
+      and _hold2 and all(r["action"] is None for r in _hold2)
+      and len(_on2) <= 1 and len(_off2) <= 1
+      and not any(r["action"] == arbitrage.CHARGE for r in _after2
+                  if _off2 and r["now"] >= _off2[0]["now"]))
 _starts = [b for a, b in zip(ROWS1 + ROWS2, (ROWS1 + ROWS2)[1:])
            if a["action"] != arbitrage.CHARGE
            and b["action"] == arbitrage.CHARGE]

goodwe_controller/test_safety129.py

@@ -38,6 +38,7 @@ logging.disable(logging.WARNING)
 import safety128_rig as R                                      # noqa: E402
 import app.main as app_main                                    # noqa: E402
 from app import lateness                                       # noqa: E402
+from app import settle                                         # noqa: E402
 
 fails = []
 
@@ -58,6 +59,17 @@ def no_gate(fn):
         app_main.Controller._readings_late = real
 
 
+def no_settle(fn):
+    """`fn()` without SAFETY-136's gentler loop: the tree this card was written
+    against (with it the same run exports -645 W, not -1 325 W)."""
+    real = settle.Settle.moved
+    settle.Settle.moved = lambda self, *a, **k: None
+    try:
+        return fn()
+    finally:
+        settle.Settle.moved = real
+
+
 def run_late(**kw):
     """Run the rig; (rig, seconds the verdict stood, first second it stood)."""
     dur = kw.pop("dur")
@@ -91,7 +103,7 @@ for units, house in ((AB, 1800.0), (A, 1500.0)):
     if len(units) == 2:
         old = R.Rig(house=house, lag_s=30.0, lag_on=ON, lag_off=ON + 300.0,
                     units=units, p1_s=5.0)
-        no_gate(lambda: old.run(ON + 300.0))
+        no_settle(lambda: no_gate(lambda: old.run(ON + 300.0)))
         check(f"{n}: without the gate the export goes below -1 kW",
               grid_min(old.rows, ON, ON + 300.0) < -1000.0)
 

goodwe_controller/test_safety135.py

@@ -0,0 +1,324 @@
+"""Runnable check for SAFETY-135: a young 15-minute period does not cost the
+night charge the whole period.  `python3 test_safety135.py`
+
+The REAL Controller (tools/opt11p3_replay.py, read_inputs + cycle, battery
+modes, the peak guard on a P1 meter) with TEST-23-like lag: 1 s cycles,
+readings 1 s old, a 5 s old meter in part 2. "Off" is the same run with
+every measured stop latching and no wait for a falling give: the tree before
+this card.
+DECISIONS/SAFETY-135-young-period.md.
+
+1. A peak-bound night charge; a period starts with a 4 s kettle spike. The
+   guard cuts at once, and the charge resumes in that period (off: it stays
+   off to the period's end). The period stays at or under the aim.
+2. A cheap run starts at 01:00 right after a give run, with a 5 s meter: no
+   start-then-cut within 60 s (off: one), and no period over the aim.
+3. A real over-aim load: the guard and the charge stop on the same cycle as
+   off, and the charge stays off while the load is on.
+4. The SAFETY-136 rig run C/s5b (house 1 800 W, an oven 2 kW 45 s in every
+   105 s, A Leftover solar 5 kW, B Cheap hours 4.6 kW): the charge starts at
+   about 01:00:32 and the guard cuts it about 60 s later on the oven. It
+   starts again 60 s after that cut (off: never in that period).
+5. Repeated spikes in one period: at most one restart, and none sooner than
+   RESTART_S after the first stop.
+
+Mutations (MUTATION.md, purged copies) are listed in the pull request.
+"""
+
+import logging
+import os
+import sys
+from datetime import datetime, timedelta, timezone
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, HERE)
+sys.path.insert(0, os.path.join(HERE, "tools"))
+logging.disable(logging.WARNING)
+
+import opt11p3_replay as rp                                    # noqa: E402
+from app import arbitrage, modetrade, packmode                 # noqa: E402
+from named_absence import nth, present                         # noqa: E402
+
+fails = []
+
+
+def check(name, cond):
+    print(f"  {'ok  ' if cond else 'FAIL'} {name}")
+    if not cond:
+        fails.append(name)
+
+
+L = timezone(timedelta(hours=1))
+D0 = datetime(2026, 11, 3, tzinfo=L)
+UTC0 = D0.astimezone(timezone.utc)
+# Local quarters: dear 00:00-01:00 (a give run), cheap 01:00-07:00, 0.30 else.
+PRICES = [0.40 if q < 4 else 0.10 if q < 28 else 0.30 for q in range(96)] * 2
+WPTS = [(UTC0 + timedelta(minutes=15 * i), 900, p)
+        for i, p in enumerate(PRICES)]
+AIM = rp.PEAK_CAP - 50
+CH = {"a": (True, packmode.CHEAP_HOURS, False),
+      "b": (True, packmode.CHEAP_HOURS, False)}
+T1 = D0 + timedelta(hours=1)                    # 01:00 local, the cheap edge
+RESTART = getattr(modetrade, "RESTART_S", 60.0)  # 60.0 on older trees
+
+
+class _Every:
+    """A period that equals every period: `_charge_stop` set to it makes
+    every measured stop latch, as before this card."""
+
+    def __eq__(self, other):
+        return True
+
+    def __ne__(self, other):
+        return False
+
+
+def _off(c):
+    # With RESTART_S 0 (see `off()`) nothing waits; every guard stop latches.
+    c._charge_stop = (_Every(), float("-inf"))
+
+
+def off(fn):
+    """`fn()` with SAFETY-135 off: every measured stop latches and no start
+    waits for a falling give, as on the tree before this card."""
+    names = [n for n in ("YOUNG_S", "RESTART_S") if hasattr(modetrade, n)]
+    real = {n: getattr(modetrade, n) for n in names}
+    OFF[0] = True
+    for n in names:                 # RESTART_S 0: no wait at a period's end
+        setattr(modetrade, n, 0.0)
+    try:
+        return fn()
+    finally:
+        OFF[0] = False
+        for n in names:
+            setattr(modetrade, n, real[n])
+
+
+OFF = [False]
+
+
+def run(house_w, start, secs, meter_s=1.0, *, choice=None, soc0=None,
+        limits=None, rating=None):
+    """Rows per cycle and the Controller, for `house_w(seconds since 01:00)`."""
+    t0 = start.timestamp()
+    house = [(t0 + k, house_w(t0 + k - T1.timestamp()))
+             for k in range(int(secs) + 5)]
+    rows = []
+
+    def cb(c, h, now, pr):
+        g = c.peak_guard
+        rows.append(dict(now=now, s=now.timestamp() - T1.timestamp(),
+                         grid=h.grid(),
+                         charge=getattr(c.arb, "action", None)
+                         == arbitrage.CHARGE,
+                         engaged=g is not None and g.engaged,
+                         reason=getattr(c.arb, "reason", None) or ""))
+    was = rp.RATING
+    if rating is not None:
+        rp.RATING = rating
+    try:
+        _st, c = rp.run("p3_ch_sell", house, WPTS,
+                        start.astimezone(timezone.utc), secs, check=cb,
+                        soc0=soc0 or {"a": 30.0, "b": 30.0},
+                        choice=choice or CH, limits=limits,
+                        n=len(choice or CH),
+                        patch=_off if OFF[0] else None,
+                        extra={"slew_w": 0, "cycle_cost_threshold_eur": 0.03},
+                        lag=rp.Lag(meter_s=meter_s))
+    finally:
+        rp.RATING = was
+    return rows, c
+
+
+def banked(c, frm):
+    """The add-on's own P1 period averages from `frm` (seconds after 01:00)."""
+    return [b.offtake_avg_w for b in c.p1.blocks
+            if b.start.timestamp() - T1.timestamp() >= frm]
+
+
+def flaps(rows, frm, to):
+    """Charge starts in [frm, to) s that stopped again within 60 s."""
+    out = []
+    for i in range(1, len(rows)):
+        r = rows[i]
+        if frm <= r["s"] < to and r["charge"] and not rows[i - 1]["charge"]:
+            if any(not x["charge"] for x in rows[i:]
+                   if x["s"] - r["s"] <= 60):
+                out.append(r["s"])
+    return out
+
+
+# ============================================================================ #
+print("1. a 4 s spike at the start of a peak-bound night charge's period")
+
+
+def spike(s):
+    return 2800.0 + (2500.0 if s >= 1800 and (s - 1800) % 900 < 4 else 0.0)
+
+
+R1, C1 = run(spike, T1 + timedelta(minutes=20), 1560)
+R1o, C1o = off(lambda: run(spike, T1 + timedelta(minutes=20), 1560))
+
+
+def period(rows, frm):
+    return [r for r in rows if frm <= r["s"] < frm + 900]
+
+
+for tag, rows, c in (("on", R1, C1), ("off", R1o, C1o)):
+    p = period(rows, 1800)
+    cut = next((r["s"] - 1800 for r in p if r["engaged"]), None)
+    on = sum(r["charge"] for r in p)
+    print(f"    {tag}: guard cut at +{cut} s, charging {on} of {len(p)} s, "
+          f"period {banked(c, 1800)[:1]}")
+_p = period(R1, 1800)
+_cut = next((i for i, r in enumerate(_p) if r["engaged"]), None)
+check("the spike trips the guard in the period's first seconds and the "
+      "charge stops there",
+      _cut is not None and _p[_cut]["s"] - 1800 <= 5
+      and not _p[_cut]["charge"])
+_back = [r["s"] - 1800 for r in _p[(_cut or 0):] if r["charge"]]
+check("the charge resumes in the same period, within 90 s of its start",
+      _back and _back[0] <= 90)
+_po = period(R1o, 1800)
+check("off, the same spike keeps the charge off to the period's end (the "
+      "defect this card fixes)",
+      any(r["engaged"] for r in _po[:5])
+      and not any(r["charge"] for r in _po[10:]))
+check("every period with the charge is at or under the aim (lag allows 2 W)",
+      banked(C1, 0) and max(banked(C1, 0)) <= AIM + 2.0)
+
+# ============================================================================ #
+print("\n2. a cheap run at 01:00 right after a give run, 5 s meter")
+for house in (2400.0, 3000.0):
+    def flat(s, w=house):
+        return w
+    R2, C2 = run(flat, T1 - timedelta(minutes=5), 1260, meter_s=5.0)
+    R2o, C2o = off(lambda: run(flat, T1 - timedelta(minutes=5), 1260,
+                               meter_s=5.0))
+    f2, f2o = flaps(R2, 0, 900), flaps(R2o, 0, 900)
+    p2, p2o = banked(C2, 0)[:1], banked(C2o, 0)[:1]
+    on2 = sum(r["charge"] for r in period(R2, 0))
+    on2o = sum(r["charge"] for r in period(R2o, 0))
+    print(f"    house {house:.0f} W: on flaps {f2} charging {on2} s period "
+          f"{p2}; off flaps {f2o} charging {on2o} s period {p2o}")
+    check(f"house {house:.0f} W: no charge start is cut within 60 s in the "
+          f"01:00 period", not f2)
+    check(f"house {house:.0f} W: the 01:00 period is at or under the aim "
+          f"(lag allows 2 W)", p2 and p2[0] <= AIM + 2.0)
+    check(f"house {house:.0f} W: the charge still runs in the 01:00 period",
+          on2 >= 800)
+    if house == 3000.0:
+        check("off, the 3 000 W house starts on the young period and is cut "
+              "within 60 s (the defect this card fixes)", bool(f2o))
+
+# ============================================================================ #
+print("\n3. a real over-aim load still cuts on the same cycle")
+
+
+def load(s):
+    return 2800.0 + (4000.0 if 1820 <= s < 2120 else 0.0)
+
+
+R3, C3 = run(load, T1 + timedelta(minutes=20), 1500)
+R3o, C3o = off(lambda: run(load, T1 + timedelta(minutes=20), 1500))
+
+
+def first(rows, key, val, frm):
+    return next((r["s"] for r in rows if r["s"] >= frm and r[key] == val),
+                None)
+
+
+_g, _go = first(R3, "engaged", True, 1800), first(R3o, "engaged", True, 1800)
+_s, _so = first(R3, "charge", False, 1800), first(R3o, "charge", False, 1800)
+print(f"    guard cut at {_g} s (off {_go} s), charge stop at {_s} s "
+      f"(off {_so} s)")
+check("the guard cuts on the same cycle as off, and the charge stops on it",
+      _g is not None and _g == _go and _s == _so == _g)
+check("the charge stays off while the load is on",
+      not any(r["charge"] for r in R3 if _g <= r["s"] < 2120))
+check("every period is at or under the aim (lag allows 2 W)",
+      banked(C3, 0) and max(banked(C3, 0)) <= AIM + 2.0)
+
+# ============================================================================ #
+print("\n4. the SAFETY-136 rig run C/s5b: start at 01:00:32, oven cut a minute "
+      "later")
+# The rig's house (s5b.ctl.json), in seconds from 01:00: 1 800 W, an oven of
+# 2 000 W for 45 s in every 105 s from 00:30 to 01:05:45, 3 000 W 00:56-00:58.
+
+
+def s5b(s):
+    w = 1800.0
+    if -1800 <= s < 345 and (s + 1800) % 105 < 45:
+        w += 2000.0
+    if -240 <= s < -120:
+        w += 3000.0
+    return w
+
+
+S5B = dict(choice={"a": (True, packmode.LEFTOVER_SOLAR, False),
+                   "b": (True, packmode.CHEAP_HOURS, False)},
+           soc0={"a": 53.6, "b": 27.4}, limits={"b": (-4600.0, 4600.0)},
+           rating=5000.0)
+R4, C4 = run(s5b, T1 - timedelta(minutes=5), 1260, **S5B)
+R4o, C4o = off(lambda: run(s5b, T1 - timedelta(minutes=5), 1260, **S5B))
+
+
+def edges(rows, frm):
+    """(start s, stop s) lists of the charge in the period from `frm`."""
+    p = period(rows, frm)
+    on = [round(b["s"] - frm) for a, b in zip(p, p[1:])
+          if b["charge"] and not a["charge"]]
+    of = [round(b["s"] - frm) for a, b in zip(p, p[1:])
+          if a["charge"] and not b["charge"]]
+    return on, of
+
+
+_on4, _of4 = edges(R4, 0)
+_on4o, _of4o = edges(R4o, 0)
+print(f"    on: starts {_on4}, stops {_of4}, period {banked(C4, 0)[:1]}; "
+      f"off: starts {_on4o}, stops {_of4o}, period {banked(C4o, 0)[:1]}")
+check("off, as on the rig: the charge starts about 30 s in, the guard cuts "
+      "it about a minute later, and it stays off to the period's end",
+      len(_on4o) == 1 and 25 <= _on4o[0] <= 40 and len(_of4o) == 1
+      and 80 <= _of4o[0] <= 100)
+check("the same start and the same cut as off (the cut is not delayed)",
+      _on4[:1] == _on4o[:1] and _of4[:1] == _of4o[:1])
+_cut4 = nth(_of4, 0, "the guard's cut in s5b")
+check("the charge starts again in that period, 60 s or more after the cut, "
+      "once only",
+      present(_cut4) and len(_on4) == 2 and _on4[1] - _cut4 >= RESTART - 1)
+check("the period is at or under the aim (lag allows 2 W)",
+      banked(C4, 0) and banked(C4, 0)[0] <= AIM + 2.0)
+
+# ============================================================================ #
+print("\n5. repeated spikes in one period: one restart, not too soon")
+_SP = (0, 20, 40, 62, 80, 300, 500)
+
+
+def spikes(s):
+    return 2800.0 + (2500.0 if any(0 <= s - 1800 - k < 4 for k in _SP)
+                     else 0.0)
+
+
+for n_ch in (CH, {"a": CH["a"]}):
+    R5, C5 = run(spikes, T1 + timedelta(minutes=20), 1560, choice=n_ch,
+                 soc0={k: 30.0 for k in n_ch})
+    _on5, _of5 = edges(R5, 1800)
+    print(f"    N={len(n_ch)}: starts {_on5}, stops {_of5}, "
+          f"period {banked(C5, 1800)[:1]}")
+    check(f"N={len(n_ch)}: at most one restart in the period, none sooner "
+          f"than RESTART_S after the first stop, and the last stop latches",
+          _of5 and len(_on5) <= 1 and len(_of5) == len(_on5) + 1
+          and all(t - _of5[0] >= RESTART - 1 for t in _on5))
+    check(f"N={len(n_ch)}: the period is at or under the aim (lag allows "
+          f"2 W)", banked(C5, 1800) and banked(C5, 1800)[0] <= AIM + 2.0)
+    _w = [r["reason"] for r in period(R5, 1800) if not r["charge"]]
+    check(f"N={len(n_ch)}: the wait says it in plain words (UX-08)",
+          any("tries again in a minute" in x for x in _w)
+          and not any("(young)" in x or "(wait)" in x for x in _w))
+
+print()
+if fails:
+    print(f"FAILED: {len(fails)}")
+    sys.exit(1)
+print("all SAFETY-135 checks passed")

goodwe_controller/test_safety136.py

@@ -0,0 +1,263 @@
+"""Runnable check for SAFETY-136: a calmer loop on a slow meter.
+`python3 test_safety136.py`
+
+With a 5 s meter and Home Assistant readings 10-15 s late the loop answers the
+same error again at each cycle and overshoots: with an oven, a kettle and hob,
+or a step the export was 3-10 times that of a meter with no lag. After a move
+of 150 W or more `app/settle.py` now runs the loop at half its gain (at most
+2 cycles) until the meter shows half of it. It is off for a meter under 4 s.
+DECISIONS/SAFETY-136-slow-meter-settle.md.
+
+The REAL Controller on TEST-23's plant (tools/safety128_rig.py). "Off" is the
+same run with `Settle.moved` doing nothing: the tree before this card.
+
+1. `Settle` alone.
+2. 5 s meter, readings 10 s late: oven, kettle and hob, a step down and a step
+   up export clearly less than with it off.
+3. 5 s meter, no lag: the same houses are no worse than a small margin.
+4. 1 s and 2 s meters: the commands are those of the run with it off, and the
+   loop never waits.
+5. The slow meter is told by its observed interval, at 4 s and 5 s.
+
+Mutations (MUTATION.md, purged copies) are listed in the pull request.
+"""
+
+import logging
+import os
+import sys
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, HERE)
+sys.path.insert(0, os.path.join(HERE, "tools"))
+logging.disable(logging.WARNING)
+
+import safety128_rig as R                                      # noqa: E402
+from app.control import Tuning                                # noqa: E402
+from named_absence import nth, present                         # noqa: E402
+from app import settle                                         # noqa: E402
+from app.lateness import MeterFit                              # noqa: E402
+
+fails = []
+
+
+def check(name, cond):
+    print(f"  {'ok  ' if cond else 'FAIL'} {name}")
+    if not cond:
+        fails.append(name)
+
+
+def off(fn):
+    """`fn()` with the settle wait off: the tree before this card."""
+    real = settle.Settle.moved
+    settle.Settle.moved = lambda self, *a, **k: None
+    try:
+        return fn()
+    finally:
+        settle.Settle.moved = real
+
+
+def oven(t):
+    return 1800.0 + (2000.0 if (t >= 300.0 and (t - 300.0) % 105 < 45) else 0.0)
+
+
+def kettle(t):
+    w = 600.0
+    if t % 400 < 120:
+        w += 2200
+    if t >= 900 and t % 90 < 30:
+        w += 1500
+    return w
+
+
+def step(t):
+    return 1800.0 if t < 320.0 else 300.0
+
+
+def stepup(t):
+    return 300.0 if t < 320.0 else 2500.0
+
+
+# name: (house, noise, run length, lag end)
+HOUSES = {"oven": (oven, 80.0, 900.0, 900.0),
+          "kettle": (kettle, 80.0, 1500.0, 1500.0),
+          "step": (step, 50.0, 700.0, 600.0),
+          "stepup": (stepup, 50.0, 700.0, 600.0)}
+ON = 300.0
+
+
+def wh(rows, t0, t1, sign):
+    """Export (sign -1) or import (sign +1) energy in Wh over [t0, t1)."""
+    return sum((-min(r[1], 0.0) if sign < 0 else max(r[1], 0.0))
+               for r in rows if t0 <= r[0] < t1) / 3600.0
+
+
+def run(name, lag, p1_s=5.0, units=("a", "b"), dur=None):
+    house, noise, length, lag_off = HOUSES[name]
+    r = R.Rig(house=house, noise=noise, p1_s=p1_s, units=units, lag_s=lag,
+              lag_on=ON, lag_off=lag_off)
+    waits = []
+    r.run(dur or length + 20.0,
+          lambda rig, c, t: waits.append(1) if c.settle.pend else None)
+    return r, len(waits)
+
+
+# --------------------------------------------------------------------------- #
+print("1. Settle alone")
+T = Tuning()
+s = settle.Settle()
+check("no move: the tuning is untouched", s.tuning(T, 500.0, True) is T)
+s.moved(500.0, 0.0, 100.0, True)
+check("a move under 150 W is not waited for", s.pend is None)
+s.moved(500.0, 0.0, 600.0, False)
+check("a meter that is not slow is not waited for", s.pend is None)
+s.moved(500.0, 0.0, 600.0, True)
+check("a move of 600 W is waited for: half the gain",
+      s.tuning(T, 500.0, True).gain == T.gain * 0.5)
+check("the meter fell 200 W of 600 W: still half the gain",
+      s.tuning(T, 300.0, True).gain == T.gain * 0.5)
+check("two cycles waited: the third has the whole gain",
+      s.tuning(T, 300.0, True) is T and s.pend is None)
+s.moved(500.0, 0.0, 600.0, True)
+check("the meter went the other way by half the move: the wait stands",
+      s.tuning(T, 800.0, True).gain == T.gain * 0.5)
+s.reset()
+s.moved(500.0, 0.0, -600.0, True)
+check("a move down, the meter rose half the move: the whole gain",
+      s.tuning(T, 800.0, True) is T)
+s.reset()
+s.moved(500.0, 0.0, 600.0, True)
+check("the meter fell half the move: the whole gain at once",
+      s.tuning(T, 200.0, True) is T and s.pend is None)
+s.moved(500.0, 0.0, -600.0, True)
+check("a move down is waited for too",
+      s.tuning(T, 500.0, True).gain == T.gain * 0.5)
+s.reset()
+check("reset ends the wait", s.pend is None)
+s.moved(500.0, 0.0, 600.0, True)
+check("a meter that turns out not to be slow ends the wait",
+      s.tuning(T, 500.0, False) is T and s.pend is None)
+check("the numbers are pinned",
+      (settle.MOVE_W, settle.SHOWN, settle.WAIT_SHARE, settle.WAIT_CYCLES)
+      == (150.0, 0.5, 0.5, 2))
+
+# --------------------------------------------------------------------------- #
+print("\n2. 5 s meter, readings 10 s late")
+tot_on = tot_off = 0.0
+for name, (_h, _n, length, lag_off) in HOUSES.items():
+    a, waited = run(name, 10.0)
+    b, _w = off(lambda: run(name, 10.0))
+    ea, eb = wh(a.rows, ON, lag_off, -1), wh(b.rows, ON, lag_off, -1)
+    tot_on, tot_off = tot_on + ea, tot_off + eb
+    print(f"    {name}: export {ea:.1f} Wh, off {eb:.1f} Wh, waited {waited} s")
+    check(f"{name}: waits at some point", waited > 0)
+    check(f"{name}: exports at most 75 % of the run with it off",
+          ea <= 0.75 * eb)
+print(f"    sum: {tot_on:.1f} Wh, off {tot_off:.1f} Wh")
+check("the four together export at most 65 % of the run with it off",
+      tot_on <= 0.65 * tot_off)
+
+# --------------------------------------------------------------------------- #
+print("\n2b. Another writer overrides the loop: the wait ends")
+halved = []
+real_tuning = settle.Settle.tuning
+
+
+def watch_tuning(self, tuning, grid_w, slow):
+    r = real_tuning(self, tuning, grid_w, slow)
+    halved.append(r is not tuning)
+    return r
+
+
+settle.Settle.tuning = watch_tuning
+try:
+    mark = []
+
+    def bump(rig, c, t):
+        # right after a cycle that started a wait, another writer moves the
+        # command, so the next cycle sees `target != loop_w`
+        if not mark and c.settle.pend and t > 330.0:
+            mark.append(len(halved))
+            c.target = c.target + 300.0
+
+    r = R.Rig(house=oven, noise=80.0, p1_s=5.0, lag_s=10.0, lag_on=ON,
+              lag_off=900.0)
+    r.run(500.0, bump)
+finally:
+    settle.Settle.tuning = real_tuning
+nxt = nth(halved, mark[0] if mark else 10 ** 6)
+check("the cycle after an override has the whole gain",
+      bool(mark) and present(nxt) and nxt is False)
+
+# --------------------------------------------------------------------------- #
+print("\n3. 5 s meter, no lag")
+for name in ("oven", "kettle", "step", "stepup"):
+    _h, _n, length, lag_off = HOUSES[name]
+    a, _w = run(name, 0.0)
+    b, _w = off(lambda: run(name, 0.0))
+    ea, eb = wh(a.rows, ON, lag_off, -1), wh(b.rows, ON, lag_off, -1)
+    ia, ib = wh(a.rows, ON, lag_off, 1), wh(b.rows, ON, lag_off, 1)
+    print(f"    {name}: export {ea:.1f} Wh (off {eb:.1f}), import {ia:.1f} Wh "
+          f"(off {ib:.1f})")
+    check(f"{name}: export at most 6 Wh over the run with it off",
+          ea <= eb + 6.0)
+    check(f"{name}: import at most 1 Wh over the run with it off",
+          ia <= ib + 1.0)
+
+# --------------------------------------------------------------------------- #
+print("\n4. 1 s and 2 s meters")
+for p1 in (1.0, 2.0):
+    for lag in (0.0, 10.0):
+        for units in (("a", "b"), ("a",)):
+            a, waited = run("oven", lag, p1_s=p1, units=units, dur=700.0)
+            b, _w = off(lambda: run("oven", lag, p1_s=p1, units=units,
+                                    dur=700.0))
+            same = ([(r[0], r[1], r[2]) for r in a.rows]
+                    == [(r[0], r[1], r[2]) for r in b.rows])
+            check(f"{p1:.0f} s meter, {lag:.0f} s late, N={len(units)}: "
+                  f"same commands, never waits", same and waited == 0)
+
+# --------------------------------------------------------------------------- #
+print("\n5. The slow meter is told by its observed interval")
+s = settle.Settle()
+for k in range(30):
+    s.arrive(float(k), k)
+check("a reading each second is not a slow meter", not s.slow())
+s = settle.Settle()
+for k in range(30):
+    s.arrive(5.0 * k, k)
+check("a reading every 5 s is a slow meter", s.slow())
+s = settle.Settle()
+for k in range(4):
+    s.arrive(5.0 * k, k)
+check("fewer than 5 readings in a minute tell nothing", not s.slow())
+s = settle.Settle()
+for k in range(30):
+    s.arrive(5.0 * k, 0 if k else 1)
+check("the same count again is no new reading", not s.slow())
+for p1, expect in ((1.0, False), (2.0, False), (3.0, False), (4.0, True),
+                   (5.0, True), (10.0, True)):
+    r = R.Rig(house=1800.0, p1_s=p1)
+    seen = []
+    r.run(120.0, lambda rig, c, t: seen.append(c.settle.slow()))
+    last = nth(seen, -1)
+    check(f"{p1:.0f} s meter: slow is {expect}",
+          present(last) and last is expect)
+# A 1 s meter on a house that changes every 5 s repeats its value 4 times in 5.
+# Where every reading arrives (the rig, a polled meter) it is not slow; where
+# Home Assistant sends a reading only when the value changes (ha_signed) the
+# same meter is slow (T3 of the review; DECISIONS).
+s, m, h = settle.Settle(), MeterFit(), settle.Settle()
+for k in range(60):
+    s.arrive(float(k), k)
+    h.arrive(float(k), k // 5)
+    m.add(float(k), 0.0, 1800.0 + 100.0 * (k // 5))
+check("every reading arrives, value changes every 5 s: not slow (the value "
+      "fit says slow)", not s.slow() and m.slow())
+check("the same meter through Home Assistant on change (a reading per "
+      "change): slow", h.slow())
+
+print()
+if fails:
+    print(f"{len(fails)} FAILED: " + ", ".join(fails))
+    sys.exit(1)
+print("all checks passed")