Semantic Error (SEM1162): An inherited variable with the same name like variable '...' does already exist in POU '...'.

A variable declared in the POU mentioned in the error message and a variable which is internally inherited have the same name. In the local variables grid, the declaration of the affected user-defined variable is marked red.

Remedy

Double-click the error message to jump to the affected user-defined variable declaration.
Rename the variable. If the variable is already in use, you can perform a refactoring.