Siemens SIMATIC S7 Manual page 16

Object Properties
of the Connection
Selection of the
Port Number
OPEN MODBUS / TCP communication via CP343-1 and 443-1
2XV9450-1MB00; Manual edition 4.3
• An ID is provided. You can change the ID if needed.
• Click on the button "Routing" and the configured connection will be shown.
• The MODBUS client must execute "Active connection establishment".
• In the register "Addresses" the port numbers are defined.
Click on "OK" and the inputs are accepted.
Save the network configuration and close the program "NetPro".
Please note that the connection ID (Local ID) has to be used when the FB is
called in the user program.
In a MODBUS communication a MODBUS server are normally addressed via
port 502, whereas a MODBUS client uses a port from 2000.
Commissioning
3-6