Using the CP 243-1, an S7-200 system can communicate via the S7 protocol with another
S7-200 system or an S7-300 / S7-400 or an OPC-based system. Using the IT protocols
SMTP, FTP and HTTP, communication is also possible with any computer system that
supports these protocols.
There are two ways to configure one of these communication modes for an S7-200 system:
● Configuration using STEP 7 Micro/WIN 32, version 3.2.3 or higher
● Configuration by an S7-200 user program
The configuration data for the IT services is located in the file system of the CP 243-1. This
is read during startup and then monitored continuously for changes. This means that every
change to this data during ongoing operation is immediately adopted by CP 243-1. All other
configuration data is stored in the data block of the S7-200 CPU. From there, this data is
read once each time the CP 243-1 restarts.
A change to the configuration stored on the S7-200 CPU by an S7-200 user program is
only possible when the CRC mechanism is disabled.
After the CRC check is disabled, the CP 243-1 is no longer able to check the configuration
data for consistency in terms of desired or undesired changes, so there is no guarantee
that the CP or the components connected to the network will function correctly.
To ensure that the configuration data of the CP 243-1 stored on the S7-200 CPU will also
be retained if a power failure occurs, this data must be stored in a retentive memory area
on the S7-200 CPU.
As default in an S7-200 system, the entire data block is defined as retentive. However, a
reconfiguration could change this default setting on your S7-200 system.
Changes to the configuration data stored on the S7-200 CPU do not take effect until the next
CP 243-1 restart. When STEP 7 Micro/WIN 32 is used for new/modified configuration of the
CP 243-1, this automatically triggers a restart of the CP 243-1 as soon as the mode changes
from STOP to RUN. If, on the other hand, the CP 243-1 is configured directly by the S7-200
user program, this configuration can be activated by the user program by calling the
subroutine "ETHx_CFG". Calling this subroutine also triggers a restart on the CP 243-1.
The TCP/IP address parameters (IP address, subnet mask, IP address of a gateway) can be
specified during configuration in one of two ways. They can be specified permanently or
dynamically (the CP 243-1 obtains the TCP/IP address parameters from a BOOTP/DHCP
server during startup).
Operating Instructions, 03/2012, C79000-G8976-C244-02