TCP port

The MBTCP Communication Driver uses port 502 as the default to contact all PLCs. This includes the port used for unsolicited messages from the PLCs that are programmed to provide unsolicited data (that is, the PLCs that are directly connected to the TCPIP_PORT; controllers under the ModbusBridge Object hierarchy cannot utilize this unsolicited messaging feature).

However, you have the option to configure the actual port to be used through the ModbusPLC object. When a non-502 port is used by the Generic Modbus PLC to communicate with the MBTCP Communication Driver, it will not be able to send unsolicited data to the Communication Driver.