Cable Length; Permitted Cable Lengths In An Mpi Subnet Segment; Permitted Cable Lengths In A Profibus Subnet Segment - Siemens SIMATIC S7-300 Hardware And Installation Manual

5.10.5 Cable length

MPI Subnet Segment
You can implement cable lengths of up to 50 m in an MPI subnet segment. This 50
m applies from the first node to the last node in the segment.
Table 5-20
Transmission rate
19.2 Kbps
187.5 Kbps
1.5 Mbps
3.0 Mbps
6.0 Mbps
12.0 Mbps
Segment in the PROFIBUS Subnet
The cable length in a segment of a PROFIBUS subnet depends on the
transmission rate.
Table 5-21
9.6 Kbps to 187.5 Kbps
500 Kbps
1.5 Mbps
3 Mbps to 12 Mbps
Longer cable lengths
If you want to implement cable lengths above those permitted in a segment, you
must use RS485 repeaters. Information on this topic can be found in the RS485
Repeater product information.
Length of the stub cables
If bus nodes are connected to a bus segment via stub cables (e.g. PG via a normal
PG cable), then you must consider the maximum possible length of the stub cable.
The following table lists the maximum permitted lengths of stub cables per
segment:
S7-300 Programmable Controller Hardware and Installation
A5E00105492-02

Permitted cable lengths in an MPI subnet segment

S7-300 CPUs
(without CPU 318-2 DP)
(non-isolated
MPI interface)
50 m
-

Permitted cable lengths in a PROFIBUS subnet segment

Transmission rate
CPU 318-2 DP
(isolated
MPI interface)
1,000 m
M 200
M 100
Maximum cable length in a segment
1,000 m
M 400
M 200
M 100
Configuring
5-45