Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 30)

Communication
3.1 Interfaces
CPU 31xC and CPU 31x, Technical data
3-2
Manual, Edition 08/2004, A5E00105475-05
Devices capable of MPI communication
• PG/PC
• OP/TP
• S7-300 / S7-400 with MPI interface
• S7-200 (19.2 kbps only)
3.1.2 PROFIBUS DP
Availability
CPUs with “DP“ name suffix are equipped at least with a DP X2 interface.
The 315-2 PN/DP and 317 CPUs are equipped with an MPI/DP X1 interface. A CPU with
MPI/DP interface is supplied with a default MPI configuration. You need to set DP mode in
STEP 7 if you want to use the DP interface.
Operating modes for CPUs with two DP interfaces
Table 3-1 Operating modes for CPUs with two DP interfaces
MPI/DP interface (X1) PROFIBUS DP interface (X2)
• MPI
• DP master
• DP slave 1
• not configured
• DP master
• DP slave 1
1 simultaneous operation of the DP slave on both interfaces is excluded
Properties
The PROFIBUS DP interface is mainly used to connect distributed I/O. PROFIBUS DP
allows you to create large subnets, for example.
The PROFIBUS DP interface can be set for operation in master or slave mode, and supports
transmission rates up to 12 Mbps.
The CPU broadcasts its bus parameters (transmission rate, for example) via the
PROFIBUS DP interface when master mode is set. A PG, for example, can thus receive the
correct parameters and automatically connect to a PROFIBUS subnet. In your configuration
you can specify to disable bus parameter broadcasting.