As a result of power failure or other event, an Ethernet connection may close on one side. The connection is said to be "half-open". Previous to this release, the PLC may have remained ‘hanging’, unable to close the Ethernet connection. The new System Operands described below can help the PLC recover and renew the Ethernet connection.
To enable PLC to disconnect when the Ethernet connection is inactive for a period of time, assign timeout values in SIs 103 -106.
To enable a PLC attempt to reconnect when there is no communication from the connected device for a period of time, assign timeout values in SIs 107 -110.
In any event, in order to enable the PLC to attempt to automatically reconnect a lost Ethernet connection, turn SB 168 Automatically reconnect (Keep Alive) ON at power-up.