Siemens Simatic S7-300 CPU 31xC Series User Manual

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
• MPI, PtP and PROFIBUS subnets
• Multi-Point Interface
• PROFIBUS DP
• MPI and PROFIBUS network components
• 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:
• MPI:
– CPU 315-2 PN/DP and CPU 317: 12 Mbps
– All other CPUs: 187.5 kbps
• PROFIBUS DP: 12 Mbps

Siemens Simatic S7-300 CPU 31xC Series Specifications

General

Series	S7-300 CPU 31xC
Power Supply	24 V DC
Communication Interfaces	MPI, PROFIBUS DP
Programming Languages	LAD, STL, FBD, SCL
Operating Temperature	0°C to +60°C
Memory	48 KB - 512 KB
Dimensions	40 x 125 x 130 mm (varies by model)