Multipoint Interface (Mpi) - Siemens SIMATIC S7-400 Reference Manual

Structure of a CPU 41x
1.6

Multipoint Interface (MPI)

Connectable Devices
You can, for example, connect the following nodes to the MPI:
• Programming devices (PG/PC)
• Operation and monitoring devices (OPs and TDs)
• Additional SIMATIC S7 programmable controllers
Some connectable devices take a supply of 24 V from the interface. This voltage is
available there in non-isolated form.
Programming Device/OP-CPU Communication
A CPU can maintain several simultaneous online connections during
communication with programming devices/OPs. By default, one of these
connections is for a programming device and one is for an OP/operation and
monitoring unit.
For more information about the number of connection resources and the number
OPs that can be connected for each CPU, refer to Chapter 4 Technical
Specifications.
Communication and Interrupt Response Times
Notice
The interrupt reaction times can be delayed by read and write jobs with a high
data volume (approx. 460 byte).
CPU-CPU Communication
There are two types of CPU-CPU communication:
• Data transfer via S7 basic communication
• Data transfer via S7 communication
You can find additional information on this in the "Programming with STEP 7"
manual.
Connector
Use only the bus connector with an angular outgoing cable for PROFIBUS DP or a
programming device cable for connecting devices to the MPI (see Chapter 7 in the
Installation Manual).
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Automation System S7-400 CPU Specifications
A5E00165965-01