Siemens S7-300 Devices capable of MPI communication, MPI/DP interface Profibus DP interface

Communication

3.1 Interfaces

Devices capable of MPI communication

•PG/PC

•OP/TP

•S7-300 / S7-400 with MPI interface

•S7-200 (19.2 kbps only)

3.1.2PROFIBUS 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		•	not configured
•	DP master		•	DP master
•	DP slave 1		•	DP slave 1

1simultaneous 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.

3-2	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05