Siemens SIMATIC C7-626, Installation, Assembly, Wiring

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3
3-4
C7-626 / C7-626 DP Control Systems
C79000-G7076-C626-01
Please observe the following rules before assigning MPI/L2 addresses:
S
All MPI/L2 addresses in a network must be different
S
The highest possible MPI/L2 address must be > the largest actual address
and must be the same for all nodes. (Exception: connecting a
programming device to several nodes; see Chapter 4).
CPs and FMs (as customized modules or in expansion racks) with their own
MPI address have the following special feature: their MPI address is
determined automatically by the C7 and assigned according to the following
system:
MPI-C7 address
(1 for C7 OP
2 for C7 CPU)
MPI addr.
C7 CPU+1 MPI addr.
C7 CPU+2
C7
CP CP IM361
Figure 3-1 Automatic Assignment of MPI Addresses for CPs and FMs
Please note the following characteristics in the MPI network:
!
Warning
Loss of data packets in the MPI network.
If you connect another CPU to the MPI network during operation, you may
lose GD packets and increase the scan cycle time.
Remedy:
1. Switch off the node to be connected.
2. Connect the node to the MPI network.
3. Switch on the node.
A C7 CPU can communicate with up to four further CPUs. They can
exchange global data. For detailed information on global data, please refer to
/231/.
Sending and receiving global data occurs in GD circles. Each C7 CPU may
participate in up to four different GD circles.
Rules for the
MPI/L2 Addresses
Special Features
of CPs and FMs
Data Packets in the
MPI Network
CPU to CPU
Communication
GD Circle
Configuring MPI Networks and PROFIBUS-DP Networks