hi there, i have also undergone difficulties in using modbus rtu of controlling VFD using Panasonic PLC. I have already downloaded memory mapping or modbus rtu of the inverter specifically the danfoss inverter but when i tested it in my program there was no response from the drive. if your familiar with the FPWinpro plc software i have used the modbus block instruction, there the parameters needed in order to run the program are: Communication port = 1 or 2 communication between PLC and inverter which is actually in RS-485 connection Modbus Fxn code = modbus 15 which writes multiple coils Start Register = 0006H coil no. 6 of the inverter which is allocated to run the inverter No. of register = 1 Master data = 0040H this is the control data in order to run fwd the inverter we can help each other and all of you guys who knows to solve our problem. thanks you so much..