Siemens S7-400 Number of Nodes, MPI/PROFIBUS-DP Addresses, Default MPI Addresses

Networking

Number of Nodes

MPI		PROFIBUS DP
127		127 *
(default: 32)	of which:	1 master (reserved)
1 PG port (reserved)		1 PG port (reserved)
		125 slaves or other masters

*Observe the CPU-specific maximum numbers in the Reference Manual CPU Data

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)	Default MPI Address	Default Highest MPI
		Address
Programming device	0	31
OP	1	31
CPU	2	31

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.

5-4	Automation System S7-400	Hardware and Installation
		A5E00850741-01