Siemens S7-400 Installation Manual page 122

Networking
Number of Nodes
(default: 32)
1 PG port (reserved)
Observe the CPU-related maximum numbers in the Reference Manual CPU Data,
*
Chapter 4
MPI/PROFIBUS-DP Addresses
In order for all nodes to be able to communicate with one another, you must assign
them an address:
• In the MPI network, an MPI address
• A PROFIBUS-DP address in the PROFIBUS-DP network
Default MPI Addresses
The following table shows the default MPI address and the max. MPI address with
which the devices are shipped:
Node (Device)
Programming device
Note
If you change the parameter assignment of the highest MPI address of the MPI/DP
interface, the new address remains set even after memory reset, voltage failure or
removing/inserting the CPU.
Rules for MPI Addresses
Observe the following rules before assigning MPI addresses:
• All MPI addresses in an MPI network must be different.
• The highest possible MPI address must be w the highest actual MPI address
and must be set to the same value for all nodes. (Exception: connecting a
programming device to two or more nodes.)
5-4
MPI
127
of which:
Default MPI Address
OP
CPU
S7-400 and M7-400 Programmable Controllers Hardware and Installation
PROFIBUS DP
127 *
1 master (reserved)
1 PG port (reserved)
125 slaves or other masters
Default Highest MPI
0
1
2
Address
32
32
32
A5E00069481-04