FB_INSTANCE_NEVER_CALLED

Severity: warn

An FB instance is declared, its outputs are read somewhere in the POU, but no call site invokes it.

Why it matters. Outputs only update when the instance is called. Reading T1.Q without ever calling T1(...) returns stale data (usually the initial value forever).

Settings. No check-specific config.

Trigger.

VAR
    T1 : TON;
END_VAR
(* no T1(...) call anywhere *)
IF T1.Q THEN ...                   (* fires. T1.Q read but T1 never invoked *)

The bot posts.

🟧 warn  FB_INSTANCE_NEVER_CALLED
FB instance T1 (TON) is read but never invoked
Outputs of an FB only update when the instance is called.

Fix. Add a call site for the instance, or remove the declaration if it isn't needed.