Profibus Dp - Siemens CPU 31 Series Technical Data Manual

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)
3.1.2

PROFIBUS DP

Availability
CPUs with the "DP" have at least one DP interface.
The 315-2 PN/DP and 317 CPUs are equipped with an MPI/DP interface.
The CPU319-3 PN/DP has an MPI/DP interface and additionally a DP 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
MPI/DP interface
•
•
•
simultaneous operation of the DP slave on both interfaces is excluded
1
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
Operating modes for CPUs with two DP interfaces
MPI
DP master
DP slave
1
PROFIBUS DP interface
not configured
•
DP master
•
DP slave
•
1
CPU 31xC and CPU 31x, Technical Data
Manual, 01/2006 Edition, A5E00105475-06