Hi,
I've implemented some countermeasures, such as grounding the 0VDC and directly connecting everything to ground. One observation I've made is that the Ethernet communication problem arises only when I use an Ethernet switch between the PLC and laptop. When I remove the Ethernet switch, there are no communication issues. I typically use the Ethernet switch to connect the HMI and PLC with the laptop. During machine operation, Ethernet isn't needed as the HMI communicates with the PLC via RS232.
I've implemented some countermeasures, such as grounding the 0VDC and directly connecting everything to ground. One observation I've made is that the Ethernet communication problem arises only when I use an Ethernet switch between the PLC and laptop. When I remove the Ethernet switch, there are no communication issues. I typically use the Ethernet switch to connect the HMI and PLC with the laptop. During machine operation, Ethernet isn't needed as the HMI communicates with the PLC via RS232.