Port a or control Modbus b? control Modbus Port from the D1200 fill parameters, port 2 from D1300 began to fill in the parameters. Specific reference to Modbus CP1
E manual chapters. Settings for baud rate, format, and so on to be consistent on both sides.
See seriaeway control Modbus Chapter, control Modbus CPU
CP1E software manual. Do not need to own a CRC check, if in turn fill D1300 start channel can