I am trying to connect a Ge 90-30 cpu 363 to a Beijer Qterm A12 HMI over Modbus rtu. The cpu is slave and HMI runs a Movicon CE master rtu driver. Communication fails and HMI displays slave's timeout error. I use a Ge rs232 to rs485 cable adapter for connection from rs485 port on CPU to com1(rs232) on HMI.

Settings: 19200, 8 bits, Even parity, 1 Stop, No flow control. Any suggestion on cable,or port setting would be appreciated.

Thanks

 

Just be sure that both devices have the same port settings and that the node (Station) ID is set properly. Also verify that the PLC's port setting matches your wiring scheme for 2 wire or 4 wire.

FYI, Port1 on that PLC is already RS-232 using it would eliminate the need for a converter, one less point of potential failure.

Please post what you have if you would like it verified.