After the READ_VAR and WRITE_VAR communication halts there will be a need to reboot the Processor if the setting of the parameter ‘Communications timeout’ is left zero (Default value).

A timeout value of zero will cause the function block to never timeout.

This results in the READ_VAR and WRITE_VAR block to never close the TCP/IP connection when the Ethernet cable is disconnected and re-connected. The Processor will need to be stopped and re-started after the Ethernet TCP/IP cable is re-connected.

To resolve the issue, define a timeout value in the READ_VAR or WRITE_VAR block.

The timeout value time base is 100ms. Therefore if you enter 10 it will be 1 second.