Siemens SIMATIC S7-200 System Manual page 255

The RS232/PPI Cable Setup for Remote Operation display guides you through the steps required
to configure the cable for the type of remote operation you desire.
If you have an earlier version of
-
STEP 7--Micro/WIN, select option
2 "PPI single master network with
a modem".
If you are using Freeport
-
communication with a modem,
select option 3.
For example, select option 1 for PPI
multi-master network with a modem
using STEP 7--Micro/WIN 3.2 Service
Pack 4 or later.
The HyperTerminal display shown in
Figure 7-41 indicates the switch settings
you need to set on the cable. The switch
settings allow STEP 7--Micro/WIN to
participate in a remote network via
modems with one or more masters and
one or more S7-200 PLCs. Such a
network is shown in Figure 7-41.
After setting the switches as indicated,
select continue. The resulting
HyperTerminal display is shown in
Figure 7-42.
The remote modem (the one connected
to the RS-232/PPI Multi-Master cable)
should be set to factory defaults. With
the remote modem set to factory
defaults, enter the AT strings required to
program the modem for operation with
the RS-232/PPI Multi-Master cable.
Typically, the only string that needs to be
sent is ATS0=1, which configures the
modem to auto--answer incoming calls
on the first ring.
If you are using a cell modem that requires a PIN, use the second AT command to supply the PIN
(refer to your modem manual for the AT commands supported by your modem). If you need to
modify the AT commands, make the selection and enter the commands required as you are
prompted for them. The prompts include example AT command strings to help you with the
formatting of the commands.
The RS-232/PPI Multi-Master cable will send these AT strings to the modem each time the cable
powers up. Make sure that the modem is powered up before or very close to the same time the
cable is powered up. Also, if you power cycle the modem, be sure to power cycle the cable. This
allows the cable to properly configure the modem and operate at the highest available baud rate.
Communicating over a Network
Modem
Telephone
Line
RS-232 Multi-
Modem
Master Cable
Figure 7-41 HyperTerminal - - RS-232/PPI Cable Setup
Figure 7-42 HyperTerminal - - Remote Modem
Chapter 7
STEP 7-Micro/WIN:
Master
HMI: Master
S7-200
241