In a data block you have assigned the system attribute "S7_m_c" to variables so that they can be operated and monitored in WinCC after OS compilation. This works with simple variables in the data block, but arrays, structures and UDTs are not transferred to the WinCC data management.
In data blocks the "OS Compile" function doesn't support any structured data types like ARRAY, STRUCT or UDTs (user-defined data types). WinCC doesn't support any declaration of structures within a structure. A data block is already created in WinCC as a structure - so no more structures can be defined within the data block.
This also applies for the definition of structures in function blocks.