Mpi Addresses Of Cps/Fms In An S7-300 - Siemens SIMATIC S7-300 Hardware And Installation Manual

Configuring
Rules: Assigning MPI/PROFIBUS DP addresses
Note the following rules before assigning MPI/PROFIBUS addresses:
• All MPI/PROFIBUS addresses in a subnet must be unique.
• The highest MPI/PROFIBUS address must be • RI WKH SK\VLFDO
MPI/PROFIBUS address, and it must be identical for each node. (Exception:
Connecting a PG to multiple nodes; refer to the next Chapter).
Differences in the case of MPI addresses of CPs/FMs in an S7-300
Table 5-13
Example:
An S7-300 CPU and 2 CPs in one unit.
You have two options for assigning MPI
addresses of CPs/FMs installed in one
unit:
First option: The CPU adopts the CP
MPI addresses you specify in STEP 7.
Second option: The CPU automatically
determines the MPI addresses of the CPs
in their configuration as follows: MPI
address of CPU; MPI address +1; MPI
address +2.
(Default)
Special features: CPU 318-2 DP
Recommendations for the MPI address n
Reserve MPI address "0" for a service PG or "1" for a service OP. You can later
connect them temporarily to the subnet. Also, assign other MPI addresses to
PGs/OPs operating on the MPI subnet.
Recommended MPI address for the CPU in case of replacement or service:
Reserve MPI address "2" for the CPU. This prevents duplication of MPI addresses
after you connect a CPU with default settings to the MPI subnet (for example, when
replacing a CPU). That is, you must assign an MPI address greater than "2" to
CPUs on the MPI subnet.
5-38

MPI addresses of CPs/FMs in an S7-300

Options
S7-300 Programmable Controller Hardware and Installation
Example:
CPU CP
SF
BUSF
DC5V
FRCE
RUN
STOP
CPU CP
MPI address MPI
address
+x
MPI address MPI
address
+1
This CPU uses only one MPI address,
including the CPs connected.
CP
CP
MPI
address.
+y
MPI
address
+2
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