Gotchas

Use this page only for library-specific caveats.

Use the shared KV Host Link Troubleshooting & Codes page for common connection, profile, address-shape, write-permission, and PLC error-code symptoms.

Current library-specific caveats

Area	Symptom	Guidance
State-changing outcome	Timeout, cancellation, close, transport loss, or malformed confirmation occurs after a request may have been sent.	Treat HostLinkOutcomeUnknownError as unknown PLC state. Inspect reason, reconcile state explicitly, and do not blindly retry.
Named aggregate timing	A large or mixed read_named result changes while it is being collected.	The helper may use multiple caller-ordered read requests in one FIFO turn; it is not an atomic PLC-time observation.
Bit-in-word write	write_bit_in_word or write_bit_in_expansion_unit_buffer can overwrite another change to the same word.	They are explicit two-request, non-PLC-atomic operations. Use PLC-side coordination or exclusive whole-word ownership, and never automatically retry an outcome-unknown result.