Siemens Simatic S7-400 - Configuration of an MPI Network

Interfaces, Networks and Data Communication for the S7-400
5-5
Automation System S7-400 Configuration and Use
A5E0044271 1-02
Simple Access to all Modules
The multi-point interface enables central access to all programmable modules
within a configuration. Additional cabling is not required, for example, in order to
access the data of a CP from a programming device.
Maximum Distance
The distance between the communication partners is determined by the length of
the cable. The total length of cabling is 50 m maximum without signal amplification.
You need an RS 485 repeater as a signal booster to bridge greater distances. For
example, with two RS 485 repeaters, you can bridge a distance of 1100 m between
communication partners. Additional RS 485 repeaters enable even greater
distances.
In Figure 5-2 you can see an example of a MPI network configuration with greatest
possible distances for an MPI network.
Max. 50m
Max. 50m
Max.
1000m
 Terminal resistor on
 Programming device connected via spur line for maintenance purposes
0 ... x MPI addresses of the stations
RS 485
repeater
RS 485
repeater






S7-400
S7-400 S7-400
S7-400 S7-400
Spur line

0
11
7
8910
345 6
OP
PG*
PG*
OP
OP
Figure 5-2 Configuration of an MPI network
Components for Communication via the MPI Interface
You can use the network components of PROFIBUS DP to configure a network
using the MPI interface.