A Simulink Identifier (SID) is a unique identifier automatically assigned to a Simulink block, model annotation, or a Stateflow object within a Stateflow chart. The SID has the following characteristics:
Persistent within the lifetime of a Simulink block, model annotation, or Stateflow object.
Saved in the model file.
If the name of a block or object changes, the SID remains the same.
You cannot modify the SID.
The SID format is
model_name is the name of the model
where the block, annotation, or object resides
sid_number is a unique number within
the model, assigned by Simulink