SAFETY-97: centre the band on the idle reading clamped to 75 W

Owner decision 2026-10-04 (review R1). A wrong idle reading more than
about 100 W off hid every refusal on that battery. Clamped under the band,
the band keeps 0 W +-25 W, so a battery reading about 0 W while refusing is
caught whatever was learned or restored. Samples are still taken to 250 W.
Beyond about +-170 W of idle a battery behaves as in 0.14.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

goodwe_controller/test_safety97.py

@@ -169,7 +169,7 @@ def small_ask():
 b, b_old = small_ask(), without_fix(small_ask)
 check("SAFETY-42: B giving nothing at a small ask, idle -100 W, is parked "
       "(not latched as not delivering in 700 s; with idle 0 W it is)",
-      not b.delivery_wd.tripped and b.idle_w == -100.0
+      not b.delivery_wd.tripped and b.idle.value == -100.0
       and b_old.delivery_wd.tripped)
 
 # ============================================================================ #
@@ -213,8 +213,11 @@ check("⭐ a charge reversing into a discharge (lag 10 and 20 s, 1 s meter) "
 print("\n3. learning the idle reading")
 _t, r = caught(2, "b", 1.0)
 c = r["c"]
-check("learned during the rest: A about 0 W, B about -100 W, and saved",
-      abs(c.inverters[0].idle_w) < 5 and abs(c.inverters[1].idle_w + 100) < 5
+check("learned during the rest: A about 0 W, B about -100 W (used: -75 W), "
+      "and saved",
+      abs(c.inverters[0].idle_w) < 5
+      and abs(c.inverters[1].idle.value + 100) < 5
+      and c.inverters[1].idle_w == -idle.IDLE_MAX_W
       and abs(c.store.data.get(unit_key("inverter-b", "idle_w"), 0) + 100)
       < 5)
 
@@ -250,10 +253,11 @@ try:
 finally:
     rig.Plant = real_plant
 b = r["c"].inverters[1]
-print(f"    refusing B reading -160 W: refused at {_t} s, idle {b.idle_w:.1f}")
+print(f"    refusing B reading -160 W: refused at {_t} s, idle "
+      f"{b.idle.value:.1f}")
 check("⭐ not learned while refused: 800 s held at 0 W reading -160 W leaves "
       "B's idle reading at -100 W",
-      _t is not None and b.refused and abs(b.idle_w + 100.0) < 1.0)
+      _t is not None and b.refused and abs(b.idle.value + 100.0) < 1.0)
 
 # Not learned while control is stopped (another owner may drive the battery)
 # or while the unit's sign watchdog has latched.
@@ -319,12 +323,58 @@ for t in range(0, 600):
 check("a reading beyond 250 W is not a sample (-300 W: never learned; a "
       "register held at 2000 W then -240 W: -240 W)",
       o.value is None and p.value is not None and abs(p.value + 240.0) < 1e-6)
-check("a saved value is clamped to 250 W, and garbage is ignored",
-      idle.IdleReading(900).w == idle.IDLE_MAX_W
+check("a saved value is clamped to 250 W, the band's centre to 75 W, and "
+      "garbage is ignored",
+      idle.IdleReading(900).value == idle.IDLE_SAMPLE_W
+      and idle.IdleReading(900).w == idle.IDLE_MAX_W
       and idle.IdleReading(-900.0).w == -idle.IDLE_MAX_W
+      and idle.IdleReading(-60.0).w == -60.0
       and idle.IdleReading("x").value is None
       and idle.IdleReading(float("nan")).value is None)
 
+# ============================================================================ #
+print("\n3b. a wrong idle reading (owner, 2026-10-04: centre clamped to 75 W)")
+
+
+def wrong_idle(n, unit, err, restore):
+    """Seconds from the cut to the refusal when the idle reading is `err` W
+    off: taught wrong during the rest, or restored wrong."""
+    cu = "a" if n == 1 else unit
+    true = -100.0 if unit == "b" else 0.0
+    if restore:
+        return caught(n, unit, 1.0, store={
+            unit_key(f"inverter-{cu}", "idle_w"): true + err})[0]
+
+    class _W(rig.Plant):
+        def advance(self, t):
+            rig.OFFSET[cu] = true + (err if t < REST else 0.0)
+            super().advance(t)
+    saved, real = dict(rig.OFFSET), rig.Plant
+    rig.Plant = _W
+    try:
+        return caught(n, unit, 1.0)[0]
+    finally:
+        rig.Plant = real
+        rig.OFFSET.clear()
+        rig.OFFSET.update(saved)
+
+
+A_WRONG = {(n, e, rs): wrong_idle(n, "a", e, rs) for n in (1, 2)
+           for e, rs in ((-250.0, False), (-150.0, False), (150.0, False),
+                         (250.0, False), (-250.0, True), (200.0, True),
+                         (250.0, True))}
+print(f"    A (reads about 0 W) refusing, idle off by E: {A_WRONG}")
+check("⭐ a battery reading about 0 W while refusing is caught whatever idle "
+      "reading was learned or restored (A, E -250..+250 W, N=1 and N=2)",
+      all(v is not None and v <= 32.0 for v in A_WRONG.values()))
+check("⭐ ...including a wrong saved idle_w of +200 W on A",
+      all(A_WRONG[(n, 200.0, True)] is not None for n in (1, 2)))
+B_WRONG = {(n, e): wrong_idle(n, "b", e, False) for n in (1, 2)
+           for e in (-150.0, -50.0, 90.0)}
+print(f"    B refusing, idle taught wrong by E: {B_WRONG}")
+check("B is caught across -150..+90 W of error in its idle reading",
+      all(v is not None and v <= 32.0 for v in B_WRONG.values()))
+
 # ============================================================================ #
 print("\n4. the rules at their edges")
 
@@ -378,8 +428,11 @@ check("compute(): a charge refusal ends when the battery takes 100 W more "
       and control.compute(actual_w=-205.0, idle_w=-100.0, **args).refused
       == 0
       and control.compute(actual_w=-110.0, **args).refused == 0)
-check("the idle bound is under the band's reach of a real delivery: 250 W",
-      idle.IDLE_MAX_W == 250.0 and idle.IDLE_ASK_W < control.PROBE_W)
+check("the band's centre stays within 75 W of 0 W, so the band keeps 0 W "
+      "+-25 W; samples to 250 W",
+      idle.IDLE_MAX_W == 75.0 and idle.IDLE_SAMPLE_W == 250.0
+      and control.REFUSED_BELOW_W - idle.IDLE_MAX_W >= 25.0
+      and idle.IDLE_ASK_W < control.PROBE_W)
 
 print()
 if fails: