Siemens Simatic S7-300, Hardware And Installation Manual, Page: 56 / 242

Configuring
S7-300 Programmable Controller Hardware and Installation
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4.10 Configuring a subnet
4.10.1 Expansion and networking options
Subnets
SIMATIC offers the following subnets, according to different automation levels
(process, cell, field and actuator/sensor level ):
•
Multi Point Interface (MPI)
•
PROFIBUS
•
Point-to-point communication (PtP)
•
Industrial Ethernet
•
Actuator/Sensor Interface (ASI)
Multi Point Interface (MPI)
MPI is a small subnet with a low number of nodes on field/cell level. It is a
multipoint-capable interface in SIMATIC S7/M7 and C7, intended for operation as
PG interface for internetworking few CPUs or for exchanging small volumes of data
with PGs.
All S7-300 CPUs are equipped with this interface.
MPI always retains the last configuration of the transmission rate, node number
and highest MPI address, even after memory reset, voltage failure or deletion of
the CPU parameter configuration.
PROFIBUS
PROFIBUS in the open, multivendor communication system of SIMATIC
represents the network on cell and field level.
PROFIBUS is available in two versions:
1. PROFIBUS-DP fieldbus for fast cyclic data exchange, and PROFIBUS-PA for
the intrinsically safe area.
2. The cell level as PROFIBUS (FDL or PROFIBUS-FMS) for fast data exchange
with communication partners equipped with equal rights.
CPUs 31xC with suffix "DP" are equipped with a 2nd interface, namely a
PROFIBUS-DP interface.
However, you can also implement PROFIBUS-DP and PROFIBUS-FMS with
communication processors (CP).
Point-to-point communication (PtP)
Point-to-Point communication is no subnet in the common sense, because only two
stations are interconnected.
For this type of communication you require PtP communication processors (CP).
CPUs 31xC with suffix "PtP" are equipped with a 2nd interface, namely a PtP
interface.