Safety Semantic Warning: The variable '...' is not used.

An external variable is declared

with the 'Global' declaration keyword in the Data List of the Safety PLC and with 'Usage = External' in a local safety-related POU,
or
only the 'Global' declaration in the Data List exists but no local declaration.

This variable is neither read nor written in the safety-related code of the respective POU.

This warning only appears for external variables but not for local variables.

Remedy:

Double-click the error in the Error List to jump to the suspected local variables table (where the declaration is marked).
Verify the "non-use" of the variable.
- Delete the local declaration if the variable is not necessary, or
- use the variable in the code, if necessary.