fix(pixii_pv): keep sunset readings valid (0.3.3)

[frahlg]

Summary

PV can disappear after sunset while fresh Pixii MQTT messages keep arriving. A phase sum of -6 W becomes +6 W after sign conversion. FTW rejects positive PV power, leaving the last accepted reading to become stale and then missing.

pixii_pv 0.3.3 reports -max(0, phase_sum) for complete, finite input. It sums before applying the limit, keeps signed phase diagnostics and leaves the generation counter intact. Missing or invalid phase power emits no PV reading. Idle polls do not replay old readings.

The negative reading may come from meter noise or inverter consumption. The report and screenshot do not establish which, or confirm the exact failure times.

Driver evidence

• Driver id: pixii_pv
• Device make/model: Pixii PowerShaper, the existing driver target. The report does not identify the exact unit.
• Firmware tested: not supplied; no hardware run with this change.
• Protocol/register source: the driver's existing MQTT meter_ext6 schema, gated by meter_source = "PV".
• Hardware test performed: none. Tests use synthetic MQTT messages.
• Known limits: no raw MQTT capture or installed FTW/driver version from the affected site. Beta validation on the affected site still needs to confirm fresh zero PV after sunset and returning production the next morning.

Safety

• The driver starts read-only, or this is a separately reviewed control change.
• Vendor signs are converted at the driver boundary.
• Cached telemetry becomes stale instead of being re-emitted as fresh.
• No credentials, serial numbers, private addresses or site data are included.

Control evidence

• HIL evidence: not applicable; this driver is read-only.
• Control changes: not applicable.

Checks

• Commits include Signed-off-by.
• make test-driver ID=pixii_pv — 65 passed, 6 skipped.
• make check — 4931 passed, 923 skipped.

The 19 new test cases cover negative, zero and positive totals, mixed phase signs, missing and invalid phase values, non-finite values, repeated night readings, idle polls, grid-only messages and morning recovery. The unchanged driver fails 15 of them.

A local comparison through FTW's Go Lua host and telemetry store also passed: the old driver leaves the last daytime reading and timestamp unchanged after five negative-total messages; the fixed driver updates to zero on each message, stops refreshing when messages stop, and accepts morning production.

Delivery

Paired Core PR srcfl/ftw#1654 moves the bundled driver pin to this PR's merge commit, 76ddd5846f18cb1a0d53d85508904d4e953421b2, and adds a Core regression test plus a patch changeset for the next beta. Signed driver delivery and activation are separate from the Core bundle pin.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-16T04:21:02.102972Z	8b93c1a	Draft marked ready

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