Data Communications Using The Pc/Ppi Cable - Siemens Simatic S7-200 System Manual

9.3

Data Communications Using the PC/PPI Cable

PC/PPI Cable
The communication ports of a personal computer are generally ports that are compatible with
the RS-232 standard. The S7-200 CPU communication ports use RS-485 to allow multiple
devices to be attached to the same network. The PC/PPI cable allows you to connect the
RS-232 port of a personal computer to the RS-485 port of an S7-200 CPU. See Figure 9-5.
The PC/PPI cable can also be used to connect the communication port of an S7-200 CPU to
other RS-232 compatible devices.
Figure 9-5
Using STEP 7-Micro/WIN with a PC/PPI Cable
STEP 7-Micro/WIN can use the PC/PPI cable to communicate with one or more S7-200
CPUs. See Figure 9-6. When using STEP 7-Micro/WIN, be sure that the baud rate selection
on the PC/PPI cable is set to the correct baud rate for your network. STEP 7-Micro/WIN
supports only 9600 baud and 19,200 baud.
Station 0
Apply termination and bias at stations 2 and 4. These stations are at the extreme ends of the
network.
The connector used at station 2 has a programming port connector. The connectors at all the other
stations do not have a programming port connector.
Figure 9-6
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02
Network Communications and the S7-200 CPU
RS-232
Station 0
PC/PPI Cable
Using a PC/PPI Cable for Communicating with an S7-200 CPU
S7-200 CPU
Station 2
RS-232
RS-485
PC/PPI Cable
Using a PC/PPI Cable for Communicating with One CPU at a Time on a Network
S7-200 CPU
Station 2
RS-485
S7-200 CPU S7-200 CPU
Station 3 Station 4
9-9