Siemens S7-400 Fundamentals, Station = Node, Segment, Baud Rate, Connectable Nodes

Networking

5.2Fundamentals

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),	Operator panels (OPs)*
WinCC
S7-400	PROFIBUS-DP master, PROFIBUS-DP slaves
S7-300	PROFIBUS-DP slaves

* Not recommended in DP operation

Automation System S7-400	Hardware and Installation	5-3
A5E00850741-01