@manyan2028 127.0.0.1 this is the local IP of the machine, not the IP of the PLC
502 the port is a Modbus port and not a port for the Ethernet/IP protocol, by default the port should be 44818
This is according to your screenshot from the mail. Read carefully how the Allen Bradley PLC is polled and exactly how you want to poll it, via Modbus, if it has such an opportunity, or still via Ethernet/IP