Siemens Simatic S7-200 System Manual page 225

Sample Network Configurations Using Only S7-200 Devices
Single-Master PPI Networks
For a simple single-master network, the programming
station and the S7-200 CPU are connected by either a
PC/PPI cable or by a communications processor (CP) card
installed in the programming station.
In the sample network at the top of Figure 7-8, the
programming station (STEP 7–Micro/WIN) is the network
master. In the sample network at the bottom of Figure 7-8, a
human-machine interface (HMI) device (such as a TD 200,
TP, or OP) is the network master.
In both sample networks, the S7-200 CPU is a slave that
responds to requests from the master.
For a single-master PPI configuration, you configure STEP 7–Micro/WIN to use PPI protocol: select either
single-master, multi-master, or PPI Advanced.
Multi-Master PPI Networks
Figure 7-9 shows a sample network of multiple masters with one slave. The programming station
(STEP 7–Micro/WIN) uses either a CP card or a PC/PPI cable, and STEP 7–Micro/WIN and the HMI
device share the network.
Both STEP 7–Micro/WIN and the HMI device are masters
and must have separate network addresses. The S7-200
CPU is a slave.
For a network with multiple masters accessing a single
slave, you configure STEP 7–Micro/WIN to use PPI protocol
with the multi-master driver enabled. PPI Advanced is
optimal.
Figure 7-10 shows a PPI network with multiple masters
communicating with multiple slaves. In this example, both
STEP 7–Micro/WIN and the HMI can request data from any
S7-200 CPU slave. STEP 7–Micro/WIN and the HMI device
share the network.
All devices (masters and slaves) have different network
addresses.
For a PPI network with multiple masters and multiple slaves,
you configure STEP 7–Micro/WIN to use PPI protocol with you configure STEP 7–Micro/WIN to use PPI protocol with
the multi-master driver enabled. PPI Advanced is optimal.
Complex PPI Networks
Figure 7-11 shows a sample network that uses multiple
masters with peer-to-peer communications.
STEP 7–Micro/WIN and the HMI device read and write over
the network to the S7-200 CPUs, and the S7-200 CPUs use
the Network Read and Network Write instructions to read
and write to each other (peer-to-peer communications).
For this type of complex PPI network, you configure
STEP 7–Micro/WIN to use PPI protocol with the multi-master
driver enabled. PPI Advanced is optimal.
Communicating over a Network
STEP 7–Micro/WIN
HMI (such as a TD 200)
Figure 7-8 Single-Master PPI Network
STEP 7–Micro/WIN
Figure 7-9 Multiple Masters with One Slave
STEP 7–Micro/WIN
HMI
Figure 7-10 Multiple Masters and Slaves
STEP 7–Micro/WIN
HMI
Figure 7-11 Peer-to-Peer Communications
Chapter 7
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