`min(moved, i_w) if i_w > 0 else max(moved, i_w)` files i_w == 0.0 under
rising-only, so the first push toward charging from exactly zero was blocked
permanently - the S-1 deadlock again, mirrored in sign. main.py resets i_w to
exactly 0.0 on every stop and every reseed, so it is a normal state.
Zero is now handled explicitly and both directions are allowed: nothing is
wound, so "may not wind further" has no referent, and a first step from zero is
bounded by the gain, the output clamp and the slew limit like any other.
Measured before the fix, at i_w == 0.0 and frozen: 12 800 of 25 920 ticks held
the integrator and 8 304 of those changed the emitted command, worst case
abandoning a 2 kW charge into a 4 kW export. Note this is NOT the same as the
reported symptom: at prev_w == 0 the command holds at 0 W either way, because
the output freeze forbids starting a charge while saturated, and that rule is
release/1.0's and unchanged. There is now a test asserting it deliberately.
Tests. The durable part is a property rather than more points: over 13 041
frozen states the integrator may be held ONLY by a correction pushing it
further from zero on the side it already sits, and any other hold fails. Both
signs at exactly 0.0. Mirrors added everywhere the suite tested one direction
of two - freeze wind/unwind while charging, i_w=-100, the export-direction
runaway, the negative clamp and slew.
DOCS: the cycles-vs-seconds deviation is now written down as a deviation - the
"> 10 s" criterion is not met as literally written, a cycle is one CHANGED
meter reading, and there is no guaranteed wall-clock window.
test_control.py: 43 -> 55 checks, all passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
`want = i_w` after the integrator bound, so at the default limit == max_w the
output clamp can never fire and `reason == "clamped"` had become unreachable.
Observability only today - nothing gates on the string - but SAFETY-03 exists
to alarm on exactly that engagement, so its hook was dead before it was built.
The integrator bound now reports "i-clamped", and that is the signal SAFETY-03
must watch: it is the one that fires on a default install. "clamped" stays
reachable for a configuration that lets the integrator run above the rail,
where both fire and the output clamp - which describes the value actually
emitted - is the one reported. Two names because the two events want different
alarms: the loop winding, versus a command that came out over the rating.
The real fix is the second half. The equivalence sweep compared
(target_w, sat_count), which is how a dead reason survived 3024 cases. It now
compares (target_w, sat_count, frozen, reason) and it catches this defect:
dropping the emit turns it red. Deliberate rename aliased explicitly, so any
OTHER reason divergence still fails.
Result of adding reason to the tuple: 105 of 3024 cases differ, and every one
of them is the i-clamped/clamped rename. Zero value divergences, `frozen`
included. Nothing else surfaced.
test_control.py: 41 -> 43 checks, all passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
S-1. The frozen branch admitted a correction only if it shrank |i_w|. That is
unsatisfiable for BOTH signs of error whenever |correction| > 2*|i_w|, i.e.
whenever the integrator is near zero, so the loop stopped moving and the freeze
could never clear - it clears when the inverter tracks, and not tracking is
what saturation means. Measured: 0 W held into a 2 kW import indefinitely,
where release/1.0 recovers on the next cycle. Re-encoded as the same asymmetric
rule the output freeze has always used: may not wind further in the direction
it is already pushing, may fall, cross zero or reverse. Same interpretation,
an encoding that cannot deadlock.
S-2. integrator_max_w defaulted to 1.5x max_w, which ADDED windup: in
release/1.0 the accumulator was the post-clamp command and could never pass the
rail. Default is now "follow max_w" (config 0 = unset). Measured on the 4000 W
load-drop sim, first cycle after the drop: 1000 W at the new default, 1800 W at
3000. DOCS row inverted - the useful direction is below max_w, and the 14 768 W
anecdote is a vendor controller, not evidence about this code.
S-3. The claim that i_w=None preserved release/1.0 exactly was false, because
the S-1 gate ran regardless of seeding. It is true again, and now asserted
rather than asserted-about: 3024-case exhaustive comparison against a
transcription of the old law, over both freeze states, both signs and either
side of the deadband. Added the carried-i_w convergence/overshoot sim that the
shipped configuration was missing.
S-4. Cycles are distinct meter values, not seconds: cycle() runs only when the
meter reading changes, so the window has no wall-clock bound. Comment and DOCS
corrected; the stall is detection latency, not a windup hazard, because the
same condition stalls the whole loop.
test_control.py: 33 -> 41 checks, all passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
The loop was in velocity form: the accumulator WAS the commanded power, so
"clamp the integrator" and "clamp the output" were the same line of code and
could not be set apart. This makes the accumulator an explicit carried value
(`i_w`), bounds it with its own `integrator_max_w`, and keeps the output clamp
where it was. Killing either mechanism now still leaves the other holding -
which is the point of the ticket, and what the new regression test asserts.
Freeze semantics: while saturated the integrator may unwind but not wind
further. A strict freeze would strand the command at whatever it reached,
because the condition that releases it is the inverter tracking again, and not
tracking is exactly what saturation means.
The integrator is re-seeded from the arbiter's actual output whenever the loop
did not get what it asked for, so entering any failsafe (all of which resolve
to 0 W) zeroes it, and the first cycle after release does not dump the stale
period as power.
test_control.py: 24 -> 33 checks, all passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
The deadband is a one-way ratchet: any resting point inside it holds
indefinitely. Import and export are separate registers on the meter, so a
loop resting at +14 W bills 0.34 kWh/day while behaving perfectly.
target_grid_w (default -10 W) moves that residue onto the export register.
Worst billed rest point drops from 15 W to under 5 W. Behaviour is unchanged
at target_grid_w: 0.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
