Tab: Modbus TCP Server – General

The tab contains the basic settings for network communication in the network.

Table 5. Modbus TCP

Server IP address
Response Timeout (ms)	Time interval for the client to wait for the response from this server. It is configured especially for this server node and overwrites the general response timeout setting of the respective client.
Port	Port number (TCP/IP) of the server. Port 502 is the default for Modbus
The following parameters are available only when they are defined in the device description.
Enable Fallback IP	: Unlocks the IP address for a second connection and additional configuration options
Second Server IP address	IP address for the second connection
Preferred Line	None: When the active connection is terminated, the driver attempts to switch to the inactive connection, if possible. When the original connection is restored, there is no switching back. Line 1, Line 2: The specified connection is given priority. This means that an attempt is made to switch back to this line at regular intervals after the connection is lost. These intervals can be configured via library parameters.
Keep both lines connected	: The connection on the inactive line is also maintained. The connection is regularly checked for availability by sending a read command. These intervals can be configured via library parameters. : Only the active connection is maintained, which means that a connection must first be established when the line is changed.

Tip

The currently active line and the CommunicationState of the inactive line can be read via the usiActiveLine and ComStateBackup outputs of the implicitly generated FB instance of the Modbus TCP Server.

Tip

The communication settings can be changed at runtime using the UpdateCommunicationSettings method. This method is available for the implicitly generated FB of this Modbus Server.

When the Enable Fallback IP option is selected, the UpdateCommunicationSettings method has no effect.