Coordinator rulings and Important findings from review r0:
1. FC23 is opt-in (new UseFC23ForMultiRegisterWrites, default false); a config
without it - including the persisted "disableFC23": false every form-saved
config carries - keeps the FC16 wire. DisableFC23 stays the hard kill-switch.
2. An explicit maxReadGap 0 means coalescing off again (its pre-lane meaning);
the gap-8 default applies only to an absent key.
3. Coils/DiscreteInputs tags persisted with a register dataType (the old
editor saved Int16) are coerced to Bool, never refused, with no deploy
warning (a warning can be promoted to a blocking error). The editor loads
them as Bool. Register region + Bool is still refused.
4. One comms-fault slot for reads and writes: a good read clears a write's
transport fault and vice versa.
Minors: Dispose writes its own Unknown health (m1); persisted region/address
are authoritative over addressString so a Family change cannot remap a live
tag (m2); a malformed-but-delivered reply no longer fails the unit fast (m3);
a fresh socket published after a concurrent dispose is torn down (m4); the
editor resets address text per tag (m5); master merged (m6); the FC23 latch
log says re-init restores it (m7). Back-compat tests use the old persisted
JSON shapes and fail without the fixes.
Refs #741
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
U1: a tag's addressString (Modicon / mnemonic / DL205 V-memory / MELSEC
D-X-Y grammar) now resolves through ModbusAddressParser with the DRIVER's
Family and MelsecSubFamily at every initialize and is authoritative; the
family-unaware gates (deploy Inspect, AdminUI parse consult) accept what
some family resolves. The tag editor gets an address-text field that
resolves with the owning driver's family and persists both the string and
the resolved region/offset/type fields; a hand edit drops the string.
DisableFC23 now gates FC23: by default a 2..121-register holding write is
one FC23 write + read-back (a unit answering exception 01, or failing FC23 at
the transport, moves to FC16 for the rest of the generation); RTU framing
deframes the FC23 reply. Live-checked: the pymodbus fixture implements FC23.
Also: the AdminUI driver form serialises ModbusDriverOptions (TimeSpan
strings), which the factory DTO never read - every timing field on the form
was dead. The DTO now accepts both shapes (*Ms keys win).
Refs #741
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
H2: a Bad/null publish drops the deadband baseline and any status change
publishes, so a device that returns holding the identical value is no longer
swallowed by |new - old| < deadband (the #527 value-only-dedup trap).
Integration case drives a real drop/restore through a loopback relay.
Refs #741
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
P3: a torn-down socket is re-dialled inside the gate (one attempt per backoff
window) instead of failing fast with 'Transport not connected' until the 90 s
comms-loss watchdog re-initialised the driver.
L3: ConnectAsync disposes the previous/failed TcpClient, DNS runs under the
per-op timeout, and the reconnect never sleeps inside the gate (the old
10-attempt backoff held it for ~81 s).
H9: an MBAP response with no PDU, or an exception PDU with no code, is a
TruncatedFrame desync rather than an IndexOutOfRangeException.
Refs #741
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty