i am wanting to add threading support to my cnc lathe. I am thinking about a 2hp delta VFD. But i don't want to spend ~100$ for just controlling it so i have simple plan. See if it can work.
The VFD needs 0-10 volts to run the motor and mach can output 0-5V pwm signals. because PWM signals cannot be converted to voltage easily, i have simple plan of using a ir led and receiver. The led will get pwm signals from mach and dim on less speed. The receiver will output high voltage when the led will be getting higher pwm signals (obviously a resistor will be in the circuit).
In addition to a controlled VFD i will get optoisolation from the PC to the VFD (everything safe). I have controlled a DC motor with mach PWM already so i guess it will work on VFD too. The circuit will cost less than 2$ and i won't have to wait for the cnc4PC card from US also.