An array tag subscribed natively used to register only its declared scalar
(publishing element 0 at Good) and was then refused wholesale with
BadTypeMismatch. The driver now hands the authored ArrayLength to the client,
which registers the whole array as raw bytes and decodes every notification.
- TwinCATTypeGuard.CheckArray plans the layout from the RESOLVED array type:
element checked like a scalar notification (width / float kind / string
kind); STRING(n)/WSTRING(n) elements stride n+1 / 2(n+1); multi-dim arrays
flattened in PLC memory order; an authored ArrayLength shorter than the PLC
array reads the leading sub-range, a longer one is refused; struct / pointer
/ nested-array elements, non-array symbols and VAR_IN_OUT refs are refused.
- CheckNotificationSize caps a native array at 128 KiB (largest registration
proven on a live TC 2.11 target); above it the tag is refused BadOutOfRange.
- TwinCATArrayCodec decodes the bytes into the element-typed CLR array.
- The poll read uses the same plan + codec instead of the Beckhoff typed array
read, which failed live for most real arrays (exact CLR element type, rank-N
for multi-dim, member arrays sliced by the under-reported TC2 symbol size).
- TwinCATNotificationRefusedException carries the refusal's status; the type
mismatch derives from it and the driver isolates either per tag.
Joseph Doherty