Cable Lengths Of Mpi And Profibus Subnets - Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual

Configuring
4.11 Planning subnets
4.11.2.6

Cable lengths of MPI and PROFIBUS subnets

Example: Installation of an MPI subnet
The figure below shows you the block diagram of a MPI subnet.
S7-300
SF SF
BUSF BUSF
DC5V DC5V
FRCE FRCE
RUN RUN
STOP STOP
PS
1
Key to numbers in the figure
(1)
(2)
(3)
(4)
(5)
4-40
3
2
2
CPU
OP 27
MPI-addr. 2 MPI-addr. 1
S7-300
3
PS CPU CPU
OP 27
MPI-addr. 13
1
5
MPI-addr. 0
PG
Terminating resistor enabled.
S7-300 and OP 27 have subsequently been connected to the MPI subnet using their default
MPI address.
CPU 31xC, 312, 314, 315-2 DP
You can also assign user-specific MPI addresses to the CPs/FMs at these CPUs.
CPU 317-2 DP
CPs and FMs do not have their own MPI address in this CPU.
In addition to the MPI address, the CP also has a PROFIBUS address (7 in this case).
Connected via a stub cable using the default MPI address for commissioning/maintenance
only
S7-300
S7-300
3
PS CPU CPU PS
CPU CPU
MPI-addr. 3 MPI-addr. 4
S7-300
3
PS CPU CPU
MPI-addr. 12 MPI-addr. 11
Operating Instructions, Edition 08/2004, A5E00105492-05
S7-300
3
PG
PS CP
CPU CPU
MPI-addr. 5 MPI-addr. 6
S7-300
3
PS CPU CPU
OP 27
MPI-addr. 10 MPI-addr. 8
S7-300, CPU 31xC and CPU 31x: Installation
3
MPI-addr. 7
PROFIBUS 4
3
FM
MPI-addr. 9