Siemens SIMATIC S7-400 Hardware And Installation Manual page 127

Example
The figure below shows a possible configuration of an MPI network. This example
clarifies the maximum possible distances in an MPI network.
S7-400
OP
3 4
Programming
device*
S7-400
OP
11
Terminating resistor switched on
Programming device connected via spur line for maintenance
0 ... x MPI addresses of nodes
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
www.gkbpx.com
S7-400 S7-400
5 6
Spur line
0
max. 50 m
OP
10 9
max. 50 m
Programming
device*
RS 485
repeater
7
S7-400
RS 485
repeater
8
Networking
max.
1000 m
5-17