Configuring
4.11 Planning subnets
S7-300, CPU 31xC and CPU 31x: Installation
4-30
Operating Instructions, Edition 08/2004, A5E00105492-05
4.11.2
Configuring MPI and PROFIBUS subnets
4.11.2.1 Overview
The next section contains all the information you require to configure MPI, PtP and
PROFIBUS subnets:
Contents
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MPI, PtP and PROFIBUS subnets
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Multi-Point Interface
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PROFIBUS DP
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MPI and PROFIBUS network components
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Example of networks - MPI
4.11.2.2 Basic principles of MPI and PROFIBUS subnets
Convention: device = node
All devices you interconnect on the MPI or PROFIBUS network are referred to as nodes.
Segment
A segment is a bus line between two terminating resistors. A segment may contain up to 32
nodes. It is also limited with respect to the permitted line length, which is determined by the
transmission rate.
Transmission rate
Maximum transmission rates:
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MPI:
–
CPU 315-2 PN/DP and CPU 317: 12 Mbps
–
All other CPUs: 187.5 kbps
•
PROFIBUS DP: 12 Mbps