Siemens Automation System S7-400 - Manual (Page 101)

Networking
5-3
Automation System S7-400 Hardware and Installation
A5E00850741-01
5.2 Fundamentals
Station = Node
Declaration: All the stations you connect in a network are referred to as nodes in
the following.
Segment
A segment is a bus cable between two terminating resistors. A segment can
contain up to 32 nodes. Furthermore, a segment is limited by the permissible cable
length according to the transmission rate.
Baud Rate
The baud rate (transmission rate) is the speed at which data is transmitted,
expressed in terms of bits per second.
• Baud rates of 19.2 kbps to 12 Mbps are possible for interfaces of the type
MPI/DP.
• Transmission rates of 9.6 kbps to 12 Mbps are possible for interfaces of the
type PROFIBUS-DP.
Note
If you change the parameter assignment of the MPI/DP interface transmission rate,
the new transmission rate remains set even after memory reset, voltage failure or
removing/inserting the CPU.
Connectable Nodes
MPI PROFIBUS DP
Programming devices (PGs) Programming devices (PGs)
Operator interfaces (SIMATIC-OP),
WinCC
Operator panels (OPs)*
S7-400 PROFIBUS-DP master, PROFIBUS-DP slaves
S7-300 PROFIBUS-DP slaves
* Not recommended in DP operation