Observable signals in the TwinCAT block diagram

Which settings influence the number of "blue signals" in the TwinCAT block diagram?

Basically the TwinCAT Target for Simulink^® needs a variable in the C/C++ code, which can be assigned to the signal in the block diagram. If a signal in the block diagram is not marked in blue, it means that either no variable exists (because it was dropped during code generation due to optimization of the code) or the variable could not be assigned.

To suppress omission of variables by code optimization, you can use Test Points in Simulink^®: see Configure Signals as Test Points in the Simulink^® documentation.

At TC TcCom Additional settings you can also set the entry Extended resolution of signals in block diagram. If this entry is active, an intensified search for assignments of variables and signals is performed. Note that this search takes time, so exporting the block diagram will take longer.