LX3V PLC COM2 can support WECON PLC protocol and Modbus Protocol.So user have to program protocol by COM2 system address:D8120 and D8126
Step1:D8126 select the protocol
Step2:D8120 configure the communication parameter
Step3:Set RS instruction to cconfigure Read/Write Bit/Word function by different function code.
Please kindly check the detail information in the link as below
http://docs.we-con.com.cn/wiki/plc/view/2-User%20manual/8.1.%09Communication/