fix(twincat): TOD write bound, historian note, driver-level refused-write test (#306)

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
2026-10-08 14:26:32 -04:00
parent 90e3fe1cf7
commit 05ed039c73
4 changed files with 46 additions and 1 deletions
@@ -152,6 +152,12 @@ found against a real TwinCAT 2 PLC:
  the decoded type — re-browse/redeploy to pick up the new node type. A tag
  authored `UDInt` against a TIME/DATE symbol is unchanged: it still reads and
  writes the raw 32-bit counter (the guard tolerates the same-width divergence).
+  **Historian:** a historized tag authored `Date`/`DateTime` now publishes
+  `DriverDataType.DateTime`, which continuous historization skips as non-numeric
+  (it was historized as `UInt32` before) — such tags stop recording. Author them
+  `UDInt` to keep historizing the raw counter. `Time`/`TimeOfDay` are now
+  `Float64` and still historize. A `TimeOfDay` write of 86 400 000 ms or more
+  is refused `BadOutOfRange`.
 - **Sizes come from the resolved data type, not the symbol.** On a TwinCAT 2
  target the Beckhoff library reports a dotted *member* symbol's `ByteSize` as if
  the PLC's byte count were a bit count (`.OPC_MACHINEDATA.PROCESSSTATUS`