Configuring
4.11 Planning subnets
S7-300, CPU 31xC and CPU 31x: Installation
4-28
Operating Instructions, Edition 08/2004, A5E00105492-05
4.11
Planning subnets
4.11.1
Overview
Subnets
Subnets available in SIMATIC for the various automation levels (process, cell, field and
actuator/sensor level ):
•
Multi-Point Interface (MPI)
•
PROFIBUS
•
PROFINET (Industrial Ethernet)
•
Point-to-point communication (PtP)
•
Actuator/Sensor Interface (ASI)
Multi Point Interface (MPI)
Availability: For all CPUs described in this document.
MPI is a small area subnet containing a small number of nodes at the field/cell level. It is a
multipoint-capable interface in SIMATIC S7/M7 and C7, designed as PG interface, for
networking a small number of CPUs, or for low volume data exchange with PGs.
MPI always retains the last configuration of the transmission rate, node number and highest
MPI address, even after CPU memory reset, power failure or deletion of the CPU parameter
configuration.
It is advisable to use the PROFIBUS DP network components for your MPI network
configuration. The same configuration rules apply in this case. Exception: OWG modules are
not allowed in the MPI network.
PROFIBUS
Availability: CPUs with the "DP" name suffix are equipped with a PROFIBUS interface (CPU
315-2 DP, for example).
PROFIBUS represents the network at the cell and field level in the SIMATIC open,
multivendor communication system.
PROFIBUS is available in two versions:
1. PROFIBUS DP field bus for high-speed cyclic data exchange, and PROFIBUS-PA for
intrinsically safe applications (requires DP/PA coupler).
2. The cell level as PROFIBUS (FDL or PROFIBUS FMS) for high-speed data exchange
with communication partners at the same authorization level (can only be implemented
via CP).