diagnostic data of profibus slave devices through CP

In main rack we have s7 CPU 315-2DP along with two nos of CP342-5 connected in same main rack.Both CP's are configured as master. Master Cp1 is connected with Simocode(21Nos),Sentron(14 Nos),Simeas P(5Nos),Siprotec(5Nos) and ET 200M(5NOs).Master CP2 is connected with Simocode(8 Nos),Sentron(3 Nos),and ET 200M(1NO).

We have to Know how to read the diagonastics status of Slaves connected with CP's. What fb fc is used for getting diagnostic data.