Read-only live gate on Elma presses Z35474 (TC3 3.1.4024) and Z34834 (TC2 2.11):
- Sum-read: every chunk came back BadCommunicationError. Beckhoff's
SumRead(IList<IgIoSumReadEntity>) ctor casts to IList<SumDataEntity>, which
throws InvalidCastException for a List<> (only an array survives via
covariance). The fake-client tests never built a real SumRead. New
AdsTwinCATClient.CreateSumRead passes an array; TwinCATSumReadConstructionTests
pins it (red on the List form) plus a falsifiability control on the library.
After the fix: 59 tags, status identical everywhere, values identical on every
non-moving tag, ~0.35-0.66 s vs ~2.7 s per poll; TC2 CE 2.11 answers sum reads.
- An unexpected sum chunk failure now logs one Warning per device (it was
invisible: the health message was overwritten by the next good read).
- Diagnostics: TC2 has no TwinCAT_SystemInfoVarList; fall back to .SYSTEMINFO /
.SYSTEMTASKINFOARR[1] once the TC3 name answers not-found (live: all six keys).
- #612 browse: Flat verified on TC3 (10,770 leaves; VirtualTree 1,459 strict
subset) — comment and docs updated, no load-mode option needed.
Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe
Joseph Doherty