The default configuration for PCS 7 is to compile the OS based on the Areas defined in the Plant View. Since a user-created DB is normally not assigned to any Area, it is not included in the OS compile, and the tags are not transferred to the OS.

There are a couple of possibilities for getting these tags into the OS.

1.Instead of using a user-created DB, create symbols in the Symbol Table with internal memory (MD, MW, MB and M). The starting address for this memory is “0”, for example a REAL number would have a memory address starting with MD 0. Then, you can set “Operator Control and Monitoring” for these Symbols.
2.Another method is to create a Function Block with Inputs, In/Out and Outputs that match your user-created DB. Then, you can place this FB in any Chart in an Area that is to be compiled for the OS.
3. Change the compilation mode. See the FAQ http://support.automation.siemens.com/WW/view/de/24023878