AbLegacy native: prove PLC-5 writes and non-N-file reads on real hardware (R07:U6) #752

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2026-11-06T15:27:07-05:00

dohertj2 commented

2026-11-06 15:27:07 -05:00

Native PCCC on PLC-5 is limited by design until there is hardware proof: Plc5WriteVerified = false (Ab.Transport/Pccc/PcccServices.cs:16-19), so every PLC-5 write is refused, reads are N-file only, and sub-elements are refused. Each surfaces as BadNotSupported with no health impact (#571). Review finding R07:U6 and the remediation plan (Lane AbLegacy, #738) call for a hardware follow-up issue to record this gap; none was filed.

Work (needs a real PLC-5):

Capture golden frames for PLC-5 typed writes and for non-N-file reads (B/T/C/R/F/ST, octal I/O per #244).
If the frames match, flip Plc5WriteVerified and widen the native file set with tests.
Otherwise keep the refusal and document the evidence.

The logixpccc path is in the same position. #592 covers SLC/MicroLogix native evidence and the libplctag-deletion decision, which depends on this.

Source: docs/reviews/2026-10-21/07-drivers-plc.md:83 (U6); docs/superpowers/plans/2026-10-22-review-remediation.md:338; docs/drivers/AbLegacy.md §Native known gaps. Related: #592, #571, #738.

Native PCCC on PLC-5 is limited by design until there is hardware proof: `Plc5WriteVerified = false` (`Ab.Transport/Pccc/PcccServices.cs:16-19`), so every PLC-5 write is refused, reads are N-file only, and sub-elements are refused. Each surfaces as `BadNotSupported` with no health impact (#571). Review finding R07:U6 and the remediation plan (Lane AbLegacy, #738) call for a hardware follow-up issue to record this gap; none was filed. Work (needs a real PLC-5): - Capture golden frames for PLC-5 typed writes and for non-N-file reads (B/T/C/R/F/ST, octal I/O per #244). - If the frames match, flip `Plc5WriteVerified` and widen the native file set with tests. - Otherwise keep the refusal and document the evidence. The `logixpccc` path is in the same position. #592 covers SLC/MicroLogix native evidence and the libplctag-deletion decision, which depends on this. Source: docs/reviews/2026-10-21/07-drivers-plc.md:83 (U6); docs/superpowers/plans/2026-10-22-review-remediation.md:338; docs/drivers/AbLegacy.md §Native known gaps. Related: #592, #571, #738.

dohertj2 added the driver/ablegacy priority:p3 blocked migrated type:followup labels 2026-11-06 15:28:00 -05:00

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Reference: dohertj2/lmxopcua#752