Appendix 
  A.1 Information about upgrading to a CPU 31xC or CPU 31x 
CPU 31xC and CPU 31x, Technical Data 
Manual, 01/2006 Edition, A5E00105475-06 
A-5 
A.1.5  Converting the diagnostic addresses of DP slaves 
Converting the diagnostic addresses of DP slaves 
If you are using a CPU 31xC/31x with DP interface as the master, please note that you may 
have to reassign the diagnostic addresses for the slaves since the changes to the DPV1 
standard sometimes require two diagnostic addresses per slave. 
•  The virtual slot 0 has its own address (diagnostic address of the station proxy). The 
module status data for this slot (read SSL 0xD91 with SFC 51 "RDSYSST") contains IDs 
that relate to the entire slave/station, e.g. the station error ID. Failure and restoration of 
the station are also signaled in OB86 on the master via the diagnostic address of the 
virtual slot 0. 
•  At some of the slaves the interface module is also modeled as a separate virtual slot (for 
example, CPU as an intelligent slave or IM153), and a suitable separate address is 
assigned to virtual slot 2. 
 The change of operating status is signaled in the master's diagnostic interrupt OB 82 via 
this address for CPU 31xC-2DP acting as an intelligent slave. 
 
 
 
Note 
Reading diagnostics data with SFC 13 "DPNRM_DG":  
The originally assigned diagnostics address still works. Internally, STEP 7 assigns this 
address to slot 0. 
 
 
 
When using SFC51 "RDSYSST", for example, to read module status information or module 
rack/station status information, you must also consider the change in slot significance as well 
as the additional slot 0. 
A.1.6  Reusing existing hardware configurations 
Reusing existing hardware configurations 
If you reuse the configuration of a CPU 312 IFM to 318-2 DP for a CPU 31xC/31x, the CPU 
31xC/31x may not run correctly.  
If this is the case, you will have to replace the CPU in the STEP 7 hardware configuration 
editor. When you replace the CPU, STEP 7 will automatically accept all the settings (if 
appropriate and possible).