hitachi wj200 vfd and modbus

ive bought a Hitachi wj200 vfd as im going to convert my mill to a 3ph motor. one of those Chinese 2.2kw water cooled spindles.

the existing motor control is controlled by a 0-10v output from a diy cnc v3 spindle board.

the Hitachi vfd has an input for 0-10v so i could use that . But i am thinking of connecting it via modbus to my PC. i use mach3.
i presume i have to plug in an rj45 connector into the vfd, configure the vfd , convert rj45 to a serial lead to the pc . then configure mach3 with a brain to operate the vfd.

but at the moment i dont have a clue how to do it.

does anyone have any experience with this sort of conversion to help me out.

regards