Does anyone do this and can tell me how to?

some posts suggest using a pwm to 10v converter and doing something or another with it

other post suggest getting a usb to RS845 connection to the VFD with varying results of success. This is using the plugin and .Dll.

can anyone give me a quick point in the best direction?

I want to try this with my 1.5kw spindle but I Will be doing this with my 3kw spindle.

Thanks.